Ceres is not considered as an asteroid and is considered as a Small Solar System Body. -- Deenoe 14 October 2006 (UTC)
There has been NO OFFICIAL STATEMENT from the IAU committee removing (1) Ceres as an asteroid. A poorly worded Q&A article that says Ceres both 'IS and WAS' is NOT a good official statement.
Using the IAU 2006 definitions an object is either a Planet, 'Dwarf Planet' (compound noun), or a Small Solar System Body (SSSB). This does not affect the definition of the older terms asteroids and comets.
Pluto is a Kuiper Belt Object (KBO) even though it is also a 'dwarf planet'. I believe that 1 Ceres will still considered an Asteroid since it orbits in the asteroid belt and has the same origin as the other asteroids. In the closing sentence, MPEC 2006-R19 states, "does not preclude their having dual designations"
Has Pallas become the 1st asteroid discovered? Has Vesta become the largest asteroid (at least until the IAU decides that since Vesta is a damaged, differentiated protoplanet that it was probably a healthy dwarf planet in the past)? *IF* Ceres is truly no longer an asteroid, because it is spherical, then those two very basic questions have new answers.
2 Pallas is similar to 4 Vesta in volume, but significantly less massive. If the IAU ever reclassifies Vesta as a dwarf planet AND officially declares that dwarf planets are not asteroids, then Pallas may someday be considered the largest asteroid. -- Kheider23:33, 17 October 2006 (UTC)[reply]
Please do not edit other comments, unless merely formatting a conversation to become more readable (e.g. by inserting proper indentations). Otherwise, such edits are unnecessary and could be considered to corrupting the original context. Thank you. --Iamunknown18:43, 18 October 2006 (UTC)[reply]
Under "Spheroid or not?", I added a link to Neptune's moon Proteus. Proteus is one of the largest non-spheroids in the solar system. Your re-edit (rv) moved the link from the moon to Greek mythology ;-) Kheider19:01, 18 October 2006 (UTC)[reply]
You removed the link again. Please consider, if doing anything, disambiguating the link. There is an article about the Neptunian moon Proteus (moon). You could have replaced [[Proteus]] with [[Proteus (moon)|Proteus]]. I am restoring the link with the pipe-link disambiguation Proteus (moon). --Iamunknown16:58, 19 October 2006 (UTC)[reply]
Since I have only been using Wiki for 1 month, I did not known how to get Wiki to link to the wiki copy of the "(moon) Proteus". The original link to Greek mythology would not help anyone trying to study spheroids. Thank you for making Proteus point to something relevant to the discussion. Kheider18:21, 19 October 2006 (UTC)[reply]
I didn't realize that you are relatively new here. Please let me formally welcome you to Wikipedia! Here are some pages that you might find helpful:
I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome! --Iamunknown19:13, 19 October 2006 (UTC)[reply]
Occulation Chords
An occulation chord is the width of an asteroid along a particular line, as inferred from stellar occulation. This is not the same as a solar eclipse: no asteroid can be observed to transit the Sun (particularly since most are further from the Sun than the Earth). The process works like this: we can predict roughly where an asteroid will pass in front a star, as seen from some part of the surface of the Earth. We then place a large number of telescopes across this region, with known positions, and measure the brightness of the star + the asteroid as a function of time. We see a drop when the asteroid passes in front of the star, and a jump when the star becomes visible again. The time of these events tells us the extent of the asteroid along a line defined by its projected velocity, a single chord. Taking many telescopes, we can construct an occulation silhouette. This process is very laborous and prone to difficulty, but was the only way to get asteroid dimensions with any accuracy until the advent of radar astronomy, adaptive optics, and spacecraft observations.
So an occulation chord passing through the equator of the asteroid is equal to the diameter of the asteroid? Does it matter that the Earth is only passing through the penumbra? Kheider20:04, 20 October 2006 (UTC)[reply]
There is no penumbra in an asteroid occulation, because the asteroid's angular size is far larger than the angular size of the star (an asteroid may subtend an angle of a tenth of an arcsecond, while stars have angular sizes in the milliarcsecond range). The penumbra in a solar or lunar eclipse is caused by diffraction (which is neglible for an object with no atmosphere) and by partial shadowing, which doesn't apply here.
An occulation chord passing through the equator is not the same as the diameter, because the diameter of an irregular asteroid is ill-defined. The occulation chords given the plane-of-sky silhouette, and nothing else. Michaelbusch22:14, 20 October 2006 (UTC)[reply]
Linking
When linking an image, template, or category without adding it to the article, use a leading : For example: [[:Category:Binary_asteroids|Category:Binary_asteroids]] Rmhermen16:24, 28 October 2006 (UTC)[reply]
Moderately Red Spectral class
When a KBO's spectral class is called '(moderately red)' what does that mean? Does that mean it does not reflect well in the visible light but reflects better in the infrared? Or does it mean that object is reddish in color? 50000 Quaoar, 20000 Varuna, and 28978 Ixion are all listed as such. 38628 Huya says, "appears to be dark red, suggesting it is covered with ancient organic chemistry." Thanks -- Kheider01:42, 2 November 2006 (UTC)[reply]
'Red' in this context means that the object is relatively more reflective in the red and near-infrared than in the blue (the reflectance spectrum slopes upward toward red). Such spectra on outer solar system objects are often caused by organic compounds, such as tholins. However, to the unaided eye these objects would be brownish or black, because of their low albedos. Michaelbusch01:49, 2 November 2006 (UTC)[reply]
Yes. Redder objects have higher V-R and B-V. On this plot, (0,0) is equal magnitude in all three bands. This is not quite the same as a perfectly white, because the bands are broad, but a white object would be at (0,0). A blue object would plot at negative B-V and negative V-R. Michaelbusch23:19, 2 November 2006 (UTC)[reply]
Not necessarily. 1994 ES2 has higher V-R, but much lower B-V. This means that ES2 has relatively more blue in its spectrum as compared to KP77. So if we looked only between V & R, ES2 would be more red, but if we looked only between B & V, KP77 would be redder. This simply is a problem with the definition of redness. Michaelbusch23:56, 2 November 2006 (UTC)[reply]
Planet visual magnitudes
Hi Kheider, I wonder if we could compare our methods of obtaining the range of magnitudes. While entering angular size values for the planets in their infoboxes, I noticed that the reference I was using (e.g. this one for Saturn) also gave peak magnitudes. The values I obtain based on this (how , I will explain below) differ somewhat from the ranges you put in a few days ago. It'd be good to sort these numbers out.
So, for example, for Saturn, that nasa fact sheet gives:
Apparent diameter from Earth
Maximum (seconds of arc) 20.1
Minimum (seconds of arc) 14.5
Maximum apparent visual magnitude 0.43
Obviously the maximum magnitude I use is right there. To get the minimum, I assume that the brightness maximum must occur at the same time as the given maximum apparent diameter, and that the minimum brightness must occur simultaneously with the minimum apparent diameter. (This is inapplicable to Venus and Mercury, since they are not in full phase at their closest approach to Earth). This consideration gives a minimum intensity that is (14.5/20.1)^2=0.520 times the maximum, assuming a circular orbit for Saturn, therefore a magnitude change of 0.709, hence a minimum magnitude of 0.43+0.71=1.14. I notice that you obtained a significantly darker minimum magnitude of 1.4, and am wondering at how that comes about. Deuar15:18, 12 October 2007 (UTC)[reply]
Hi Deuar. I used "A Field Guide to the Stars and Planets" (Pasachoff, 1983) for some of the values, and I used JPL Horizons to confirm the values.
You are right there is deviation based on the source and probably the methods used. I do agree that maximum apparent diameter is important, but keep in mind that the "Sun-Target-Observer angle" (target's apparent PHASE ANGLE as seen at observer's location) might affect magnitude. Some of NASA's own sources conflict one another. :-)
NASA Reference Publication 1349 lists Mercury as high as -2.3 (full phase) on May 19 2006. I went with -1.9
Different sources list values of -4.7 and -4.6 for Venus.
I have confirmed Mars (using Horizons) at -2.88 on 2003-Aug-29: You will need to set the "Target Body" as MB:Mars, the date range to cover 2003, and include the QUANTITIES: 9 (vmag) and 20 (range AU).
I can not get Jupiter's brightest magnitude greater than Mars's maximum in our lifetime.
I have heard (can not remember the source it was years ago), that when tilted at their maximum of 27 degrees, such as in 1988, that the rings increase Saturn's brightness by 0.2 to .7(?) magnitude. The book "A Field Guide to the Stars and Planets", does list Saturn at +0.2 opposition magnitude for 1985 through 1989. In 1984 with the rings only tilted 20 degrees Saturn is listed at +0.3. NASA Reference Publication 1349 lists Saturn at -0.2 (yes, that is a minus) on Jan 2 2004! The +1.47 (Horizons) value for Saturn on 2017-Oct-23 probably does not account for the rings either.
Numbers I used (vs generated with Horizons)
Mercury -1.9 2051-Jun-04 -2.20 (brightest when full)
Venus -4.6 1989-Dec-18 -4.57 (brightest when cresent)
Mars -2.9 2003-Aug-29 -2.88; 2021-Jul-11 1.84
Jupiter -2.8 2010-Sep-20 -2.79
Saturn -0.24 1973-Dec-23 0.42; 2017-Oct-23 1.47 (error since rings tilted a lot!?) (File:Saturnoppositions.jpg)
Uranus 5.5 2048-Feb-25 5.31; 2008-Feb-26 5.95
Neptune 7.7 2032-Oct-07 7.80; 1973-Dec-04 8.02 Kheider19:28, 12 October 2007 (UTC)[reply]
Yep, it's complicated. Albedo can vary with phase angle and orbital location (e.g. Pluto, Mars, Uranus?) as well. However, i would suppose that the phase angle wouldn't affect the min/max values for the planets external to Earth, since both cases should occur when we view the full face at opposition, or just next to the Sun. This might be a different matter for inclined objects like Pluto or asteroids, though. There's also a matter of which face we're viewing, or the rings of Saturn. Those rings could account for the discrepancy at the minimum magnitude we see if the maximum value given in my fact sheet took them into account (as was probably the case). Pity the fact sheets I know don't explain how the values were obtained! Anyway, I see that you've gone into lots of detail in your investigation, so I'm happy to trust your judgment :) Incidentally, how did you get Horizons to give you magnitudes? I briefly tried looking for a magnitude-related field there, but couldn't find it. Deuar22:05, 12 October 2007 (UTC)[reply]
Go to Horizons. Make sure it is set to Ephemeris: OBSERVER. Go to "Table Settings" (2nd from the bottom) and click on the blue "change". Make sure that "9. Vis mag. & Surf Brt" has a check mark next to it. :-)
Kheider22:37, 12 October 2007 (UTC)[reply]
Thanks, I see I was using the wrong Ephemeris type (elements). So, comparing the Horizons magnitude to that given in your new reference, there is a 0.3 difference in brightness (dimmer in Horizons), which is presumably due to the rings. In Horizons they mention that they don't take into account the illumination angle of the rings, but this is ambiguous - are the rings taken into account or not overall? what about viewing angle? etc. It looks like a mess, and any own calculations are bound to be bordering on original research due to the complexity of the thing. :( Well found reference, then! :) Deuar13:20, 13 October 2007 (UTC)[reply]
It does not appear as if Horizons or the NASA Fact Sheet consider Saturn's ring system. I have updated Saturn to magnitude -0.24 for the 2000-12-08 opposition at ring tilt 24° / solar phase angle 0.038. I wonder how bright Saturn was at opposition in 2002-12-17 when it was at ring tilt 26.5° / solar phase angle 0.027? This abstract does not seem to publicly show it.
-- Kheider23:59, 14 October 2007 (UTC)[reply]
On 27 December, 2007, Did you know? was updated with a fact from the article 2007 WD5, which you created or substantially expanded. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
Thank you for the heads-up. I moved the "Horizons1223" citation details to top ref to prevent the ref error that did not exist on 21:35, 3 January 2008. Perhaps citation details should not be placed in external link sections. -- Kheider (talk) 20:14, 27 January 2008 (UTC)[reply]
Sedna
It might or might not be unlikely, who knows if the astronomical community wants to enlist another planet? I know I'm for it. Besides, Mercury's probably tired of being the littlest! Secondly, size isn't -currently- use to decide which objects get to be "Planets". Thirdly, Eris doesn't cross Sedna's orbit, check the latest version of Celestia if you don't believe me.
Mass (which is Volume*Density aka size) is used to determine if an object can be orbitally dominant. And a lot of the above statements do not comply with NPOV policies. -- Kheider (talk) 22:51, 16 February 2008 (UTC)[reply]
They don't. I admitted it, but neither is your insistence that Sedna can't be a planet. And as I'd type before, there's only three standards by which a 'planet' is a 'planet,' and "orbital dominance" (except in the case of planets with moons) is not one of them, especially if we're talking about unknown Solar System bodies. You can type until you have carpal-tunnel, but the rules won't be changing until next year. -- IdLoveOne (talk) 02:10, 17 February 2008 (UTC)[reply]
For helping get Neptune to FA, and for coining the phrase "a lot of inbred rocks", to which I chortled heartily, I award you the science barnstar. :-) Serendipodous12:46, 14 March 2008 (UTC)[reply]
Cite to abstract or paper
Hey mate, about your change to go to the abstract. I understand citing the abstract as it is na HTML and not PDF, but can I still cite the pages where that info appears, even if citing the abstract? Samuel Sol (talk) 15:17, 17 March 2008 (UTC)[reply]
That was one of the first articles that I wrote. I just updated it some. I know that the JPL Small-Body Database Browser lists it as a Cubewano. But I am not sure how official that is given that it was only observed over two nights and is considered lost. Should we use that as the reference? -- Kheider (talk) 16:25, 22 May 2008 (UTC)[reply]
I'm on the verge of starting an edit war, and having just got blocked for edit warring I really don't want to start over again. I could use a third person arbitration before things get hairy. The issue is quite simple, but rather fraught. There's an article called "Hypothetical trans-Neptunian planets" that was created as a merge article for the articles on the ninth planet and the tenth planet. I've never been a fan of this article; it's meandering, vague, gossipy, unsourced and lacking in anything approaching historical and scientific rigour. Since much of what it said was already in the Planet X article, which is far better sourced and organised, and since no one had made any substantial edits to the other article in months, I decided to merge the other article with Planet X, assuming no one would even notice, let alone care. However, a few days later, to my absolute shock, someone showed up who apparently cared. User:The Tom not only reinstated the other article, but began removing similar material from "Planet X", much to my chagrin, as the material in Planet X was cited and the equivalent material in the other article was not. Eventually we came to a kind of compromise (although not one I liked very much) that "Planet X" would be strictly about Lowell's idea, with all other hypothetical trans-Neptunian planets kept in the other article. Specifically, the other article was to hold material on the recent announcement by Patryk Lykawka of Kobe University that gravitational effects suggest the presence of a large planet in the outer Solar System. Since this is essentially the same rationale for Lowell's Planet X, Lykawka's planet is called "Planet X" in the media. There are also other "Planet X"s out there, proposed by other astronomers.
Nonetheless, I held for a few days, because I didn't particularly care. However, today, a slew of information has been added to the Planet X article about Lykawka's planet, and I realised that if I was to hold to Tom's separation policy I would be spending the rest of my Wiki career removing this information, which I didn't particularly want to do, especially since I felt it should be there anyway, and that the other article wasn't worth saving. So I reverted the merge and reinstated all the old material. But I figured Tom would burst his gasket when he found out, so I thought I'd ask for a second opinion. Let me know what you think. Serendipodous14:46, 20 June 2008 (UTC)[reply]
Solar system's fate
What you mean as summary by mars and gas giant may be rip by white dwarf star? I thoguht Venus and Earth may or may not survive over sun's giant star stage. I thought Venus has slightly less than to survive than Earth. mars is likely to survive, but not positively.--FreewayguyMsgUSC03:37, 27 June 2008 (UTC)[reply]
Sorry it took me a little time to check sources with Google. See On the Final Destiny of the Earth and the Solar System (Rybicki & Denis 2001). It does appear as if the popular view is that Mercury is almost certainly a goner unless some other process alters its orbit. Venus is "most likely" to be destroyed. Earth is likely to be destroyed, but is more of a coin flip given the limited knowledge we have. So if the Sun engulfs Mercury, Venus, and Earth, Mars will likely be the closest planet to the (white dwarf) Sun. Then over trillions of years passing stars will slowly strip the gas giant planets from the weakened Sun. So perhaps Mars will be the last planet standing. But obviously this is not definitive. -- Kheider (talk) 05:51, 27 June 2008 (UTC)[reply]
Yeah, Serendipodous and I have been discussing the whole 1999 TD10 issue and trying to figure out where to come down. I have quite literally found contradicting sources: some say centaur, some say SDO... so perhaps the best thing would be to remove it for now, but actively pursue this question on the talk page. I'll remove it... Ling.Nut(WP:3IAR)04:24, 18 July 2008 (UTC)[reply]
Kheider, is there any actual proof that all of the centaurs will be removed from their orbit? Because, especially in the case of Chariklo which doesn't cross any "planet's" orbit, I don't think the article should say that -- especially without citations. As I said in my edit summary, it seems too intangible and unlikely that they all will or that it could be proven that they all will.
In fact, I think I read somewhere that the centaurs between Saturn and Uranus (Chariklo) could survive there for the "lifespan of the Solar System" or words to that effect. --IdLoveOne (talk) 01:42, 28 August 2008 (UTC)[reply]
I added a reference to Jewitt2006 that shows that Centaurs have "short dynamical lives". So, yes all Centaurs will have their orbits rapidly changed. A few of the lucky ones will achieve an orbital resonance that can last for a 3 Myr integration. I do not recall reading a statement that any centaur has an orbit that is stable over the life time of the solar system. -- Kheider (talk) 14:56, 28 August 2008 (UTC)[reply]
Is Chariklo one of the ones that have a long-lasting orbital semi-permanence? What about the asteroids? Will they be thrown from the Solar System or are they permanent? --IdLoveOne (talk) 22:52, 31 August 2008 (UTC)[reply]
According to Horner2004, Chariklo is estimated to have a long orbital half-life of about 10.3 Myr. The typical Centaur has a mean orbital half life of about 2.7 Myr. Remember that Centaurs are Kuiper belt objects that have been scattered so that they flirt with the dominant giant planets. The main belt asteroids are on low eccentricity orbits that do not flirt with major planets. -- Kheider (talk) 05:04, 2 September 2008 (UTC)[reply]
Gravity Simulator shows Eris in a 17:5 resonance with Neptune and Makemake (2005 FY9) in an 11:6 resonance with Neptune. Having said that I have never used the program so maybe they are merely in a near resonance with Neptune. I am wondering if DES is showing Eris not keeping (removed?) a 17:5 resonance with Neptune over a 10 Myr integration. -- Kheider (talk) 14:44, 11 September 2008 (UTC)[reply]
If this is true, it should be mentioned in their articles, not in the external links, but I would prefer some more scholarly refs be employed to ascertain it. Serendipodous15:12, 11 September 2008 (UTC)[reply]
The Gravity Simulator web pages is using old data for both Makemake and Eris. What appeared to be mean-motion resonances with the data released shortly after discovery, turned out to be simply near-resonances. I'm the author of that web page. I'll update it soon to reflect the current data. I found this discussion from my web logs. —Preceding unsigned comment added by 71.131.186.100 (talk) 05:53, 15 September 2008 (UTC)[reply]
You changed the diameter estimate in the article from "1300-1800" (my edit) to "1200-1600". It seems the source we both used (Brown 2007) is self-contradicting: in the section on Sedna it gives the lower estimate, in Table 1 at the end it gives the higher one. Maybe we should find a better reference. --Roentgenium111 (talk) 16:02, 26 September 2008 (UTC)[reply]
Actually, if you go to the wikipedia article, it mentions that the mean radius is 256 km. Do you think this is true? Either way I would be wrong, but 130 km is definitely nowhere near 256 km. Please answer - Interchange88—Preceding undated comment was added at 20:54, 26 September 2008 (UTC).[reply]
If you check the edit history of the article, you wil see that the mean radius has been changed/revised a few times. I will upload a more up-to-date comparison soon. Thanks for pointing that out - --Interchange88 (talk) 17:21, 6 October 2008 (UTC)[reply]
K, I'm not so sure that ref you provided would stand up to GA scrutiny. It's certainly not a published source, and borders on original research. Serendipodous18:15, 29 September 2008 (UTC)[reply]
I have been trying to give this some thought. There appears to be difficulty in figuring out the diameter (within a factor of about 2) for typical objects beyond Saturn. For example 2060 Chiron was estimated as 208km in diameter by Campins in 1994, 142km in diameter by spectroscopic observations in 2003, and 230km in diameter by Spitzer in 2007. Since it is not a binary object, we have no idea what it's mass/density is. So for non-binary TNOs I have some confidence in the diameters, but no real confidence in the "unreferenced wiki-assumed" masses/densities.
For the main belt, since it is so much closer and been studied longer, the diameters are known fairly well. But even the mass of 2 Pallas has recently varied from 3.1×1020 (Hilton1999) to 2.3×1020 (Goffin2001) to 2.1×1020 (Baer/Chesley2008). The mass calculations of Pallas and Ceres are interconnected, as the mass of one goes up, the mass of the other will go down. Mass estimates of 4 Vesta have been consistent
52 Europa (300km) was considered the sixth most massive asteroid at 5.2×1020 kg (Michalak2001), but (Baer/Chesley2008) seem to believe it is highly porous at 1.9×1019 and may have suffered a severe collision. Even 9 Metis (a 190km asteroid that may be the core remnant of a disrupted large asteroid) may be more massive. A lot of asteroids are just starting to get their first mass estimates. -- Kheider (talk) 19:09, 16 November 2008 (UTC)[reply]
How many of these do you think knowing the masses of Vesta and Ceres (and if we're really lucky and get a Dawn flyby, Pallas) will enable us to actually measure, even if crudely? kwami (talk) 09:09, 17 November 2008 (UTC)[reply]
Unfortunately it will probably only reduce the error bar on the calculations. But since the mass of other asteroids are often based (directly or indirectly) on these large perturbers, it will help. Actually going to Ceres will greatly reduce the error bar on Pallas since Ceres and Pallas are one anothers greatest perturbers. -- Kheider (talk) 14:53, 17 November 2008 (UTC)[reply]
Ixion
Hey Kheider,
You recently updated the estimated mass of 28978 Ixion. Could you also update and ref the diameter?
Done. Though keep in mind almost all TNOs assume a large body density of 2.0 g/cm³. One could easily make an argument that we should be using a density "guess" of 1.5 or even 1.3, but at least it puts the generic non-binary TNOs on a level playing field. -- Kheider (talk) 15:03, 17 November 2008 (UTC)[reply]
Just a quick reminder that this article is undergoing a GA reassessment as part of the GA sweeps. It has been on hold for over two weeks, but several concerns remain. If they are not addressed soon, I will have to delist the article. Because it is part of the Main asteroid belt Featured Topic, this would also mean that the Featured Topic would be delisted. There's not much left to do, so any help you can provide would be great. The reassessment page is here. Thanks, GaryColemanFan (talk) 22:45, 20 November 2008 (UTC)[reply]
I think, instead of manually redoing the list one at a time
It might be simpler just to make the list sortable, and then sort it. Also, I think radius and surface gravity can also be included. I'll help you with it if you want to do it. Serendipodous18:53, 29 November 2008 (UTC)[reply]
So far I am just trying to get the mass list in the correct order for the asteroids through about 65 Cybele, given 2008 knowledge. I am editing the main articles. Per our above Featured lists talk, I think it would be good to start working on such a sortable list for radius and mass. I doubt the surface gravity has been re-calculcated in the infobox of many asteroids since the old 2005-2006 estimates. I know that I seldom bother to re-calculate the gravity myself when I know the mass is just an educated guess. Could we create an automatic process to take the radius and mass and spit out the surface gravity/escape velocity? -- Kheider (talk) 21:12, 29 November 2008 (UTC)[reply]
Well I checked Karkoschka of 2001 and it appears you are right. In the table V of Karkoschka the values of are listed (a and b are are major and minor semi-axis of the moon's prolate ellipsoid). However true average radius is . I probably uncritically used that strange value.
If you want to read this paper I uploaded it to filefactory (see http://www.filefactory.com/file/4ba0e6/n/Icarus_Karkoschka_2001c_pdf ) Ruslik (talk) 08:15, 12 December 2008 (UTC)[reply]
I subbed a planet infobox for the comet infobox, which allowed me to include the physical characteristics. Unfortunately, it also forced me to buch the dates for the last and next perihelia into one line. Serendipodous01:00, 19 December 2008 (UTC)[reply]
No, not yet. I still have some more work to do. I have been trying to decide how to improve the key. I know a lot more will need to be done even after that, but at least it will be a step in the right direction for sourcing the accuracy of the numbers. I have also been in contact with JPLSSD (Last Updated: 2008-Dec-20) and they have finally updated their sizes and albedos for the Uranian irregulars per Sheppard2005. :-) -- Kheider (talk) 19:03, 22 December 2008 (UTC)[reply]
I've been thinking; what if we dumped the lower list and just focused on creating an absolutely comprehensive list of objects above 100 km in radius? Serendipodous20:22, 24 December 2008 (UTC)[reply]
I think people will still want to see smaller well known objects on the list. I don't think including the 2nd list harms the main list. Though it may be better to only include objects with known sizes and decent estimates on the mass for the lower list. Still brainstorming... -- Kheider (talk) 21:58, 24 December 2008 (UTC)[reply]
I want to expand the "radius only" objects in the 100km+ table to include mass and volume, assuming sphericity and Pluto's density. I was wondering if you thought that was a good idea. Serendipodous13:40, 19 January 2009 (UTC)[reply]
I will start adding the "R Radius has been determined by various methods, such as optical (Hubble), thermal (Spitzer), or direct imaging via spacecraft" objects. Since these are the only objects with decent diameters, though still unknown densities/masses. But I do feel that inserting generic values for the unknown diameters (assumed albedos of 0.09 objects), with unknown masses might be counter productive to a reliable (quality) list. -- Kheider (talk) 20:55, 19 January 2009 (UTC)[reply]
Will do. :-) Though with some of these changes I feel like I am walking a fine line with {{OR}}. But I guess the values are based on Burton, the current estimated JPL absmag (H), and a generic assumed albedo of 0.09, thus the results are reproducible. Johnston's list is good, but is not always based on the current absmag. -- Kheider (talk) 21:50, 11 March 2009 (UTC)[reply]
It's a bit late to start worrying about that. You've pretty much created the mass and radius figures for every listed minor planet on this site, and, I have no doubt, many of your figures have now entered the media and, perhaps, are even being taken as read by many people who have never looked at Wikipedia askance. You're creating facts as much as reporting them. And while yes that is a bit Orwellian I can't really offer you a better alternative unless the scientific community finally decides to take Wikipedia seriously. Serendipodous17:16, 12 March 2009 (UTC)[reply]
To make things scarier some of the pages I have not edited (generally the smaller bodies) do not directly site Johnston and do not show either the size or albedo as "(assumed)". To be accurate a lot of mass estimates have historically been done by Urhixidur, ie see: Sycorax and TC302. Even Ruslik has done a few, see Orcus (Russ assumed a density of only 1.5)... -- Kheider (talk) 18:55, 12 March 2009 (UTC)[reply]
Sorry if that post came across as a bit accusatory. It's not so much meant to reflect on you as on the strange situation Wikipedia's in right now. I wish there was a better alternative, but there isn't right now. All we can do is be sure to clearly state our sources. Serendipodous10:36, 13 March 2009 (UTC)[reply]
Thanks for the support. But the truth is, if you have this concern, someday someone else will. At least by showing my math someone can always reproduce or re-do my numbers using a different radius or density. -- Kheider (talk) 15:48, 13 March 2009 (UTC)[reply]
I based my albedo range off of Johnston's table and what appears to be a common trend for larger TNOs (say 800-1400km range) to have higher albedos than the common "assumed 0.09 value". I am assuming that 2007 OR10 is a little smaller than Sedna. So for bodies 800 to 1400km in diameter I assumed a likely albedo range of 0.15 to about 0.40. Only the very large bodies appear to have extremely high albedos. Not perfect but a good starting point. -- Kheider (talk) 20:46, 20 January 2009 (UTC)[reply]
I am just referring to the Johnston and Wikipedia assumption that a typical TNO has an albedo of 0.09 (and density of 2.0) until proven otherwise. -- Kheider (talk) 20:54, 20 January 2009 (UTC)[reply]
Sure, but an assumed albedo of 0.09 with an absolute magnitude of 1.9 results in a diameter of 1800. Even Sedna (absolute magnitude 1.6) doesn't really claim to be that big anymore. See: User_talk:Kheider#Diameter_of_Sedna. I would recommend using Ref 6 (Dan Bruton) from the 2007 OR10 article. Then you can properly use "Assuming an albedo of 0.15". -- Kheider (talk) 08:18, 21 January 2009 (UTC)[reply]
There are some discrepancies between the largest asteroids on this page and the asteroids on the size list. Since neither is cited, I don't know which is right. Serendipodous13:31, 23 January 2009 (UTC)[reply]
Yes, those 3 were making me make weird faces back in November: :-)
In early December (edit), I did update 94 Aurora to show a decent occulation using 9 chords. It showed a size of 225×173 km (geometric mean 197). JPL shows it as 204.89 using IRAS data. So 94 Aurora is in the correct ballpark.
532 Herculina: JPL shows 222km per IRAS data. The Institute of Applied Astronomy (2006) also shows 222.19. But I am not sure I want to trust (or suggest to wikipedia) density and mass data from a 2006 source when there have been so many asteroid density-mass changes in the last two years.
451 Patientia is listed by JPL as 224.96 per IRAS data. Again the Institute of Applied Astronomy (2006) shows it the same.
Baer really wouldn't have data on these TNOs. They are basically too far away and too recently discovered. So unless it is a known binary object with a resolved orbit, Baer won't be much help for distant KBOs. These seem to be the red links from List of plutoid candidates. In the past I have converted some of the more standout red links to articles. I will recheck into some of them. But keep in mind you can always get a peak at the object by simply cutting and pasting into JPL or DES.
Sorry for having to take out the dimensions you put; I couldn't find those exact set of numbers anywhere in the tables of Rabinowitz et al. or Stansberry et al.. Feel free to change it back, if you could let me know where they were, or if you prefer we can discuss it instead on the talk page at Haumea. Iridia (talk) 10:43, 3 February 2009 (UTC)[reply]
Right, thanks. I was looking at that exact table last night and not connecting their ax to your figures - must have been half asleep. :P Iridia (talk) 05:02, 4 February 2009 (UTC)[reply]
I think the poster was just stirring the pot (vandalism more than crazy). The poster said (1) "Eris would take twenty years to get if traveling at the speed of light" (wrong), (2) "cover ups", (3) "theory is for the planet to come to us and destroy", and (4) "bible". I figured a rv might be called for. It certainly did not look like a legit concern about improving the article itself. -- Kheider (talk) 18:58, 10 February 2009 (UTC)[reply]
Hey, Could you add something at orbital resonance about resonance orders and the strength of a resonance? I can't tell from your description at Haumea if the resonance gets weaker as the ratio approaches 1 or as it approaches 0; the wording ("the lower the difference") makes it sound like the former, but that would mean a 1:1 resonance is the weakest possible. kwami (talk) 21:20, 10 February 2009 (UTC)[reply]
This pushes what I understand. To make matters more complicated, the 1:1 superresonance is another type of periodic interaction that a 3:2 resonant body can experience in its orbital motion that enhances stability against Neptune. Over 3.7 million years, Pluto's Kozai resonance will make the eccentricity vary from 0.21 to 0.275 and the inclination vary from 14.4 to 17.5. Orcus can get an inclination as high as 23.5.-- Kheider (talk) 22:54, 10 February 2009 (UTC)[reply]
I notice you do that when you're attempting to calculate the masses of small objects. Do you also assume that they are spherical? I need to know because I might have to do it. Serendipodous16:34, 6 March 2009 (UTC)[reply]
I don't know. This is one of those situations where Wikipedia's power to seep under the radar into the public sphere can be quite disturbing. Lazy journos (ie all of them) use Wikipedia for quick info, and then Wiki's stats get published in newspapers and magazines as if they're holy writ. I'm not criticising your work (in fact I think you've done a stellar job creating all those minor planet pages), but Wikipedia really needs the authority of an informed professional in these matters, and since informed professionals seem to regard Wikipedia with detached amusement or outright disdain, it's left to us to cobble together what we can from wherever we can get it. So I don't really have a solution, other than to use common sense and work on a case by case basis. For most plutoids, 2.0 is a perfectly valid assumed density, as it it Pluto's density. For comets, a density of less than one would be appropriate, and for asteroids, a density perhaps of 2.5. Not very scientific I know. Serendipodous21:43, 6 March 2009 (UTC)[reply]
Good. It sounds like you are thinking along the same lines that I am. It is always good to get some reassurance that I have not wondered into lala land. -- Kheider (talk) 23:28, 6 March 2009 (UTC)[reply]
I think we need to coordinate
I've been using 2.0 density to complete the top list, and including Earth comparisons, which works somewhat against your point in the introduction, which I hadn't noticed before now. So I think we need to come together on what should be included. Serendipodous19:40, 15 March 2009 (UTC)[reply]
For Dwarf Planets Candidates I think a density assumption of 2.0 is fine, and seems to be the normal guess, though 1.5 is a good number also. I am not sure exactly what you are refering to, we are guessing at the density for many of these objects. I used an assumed density of 1.5 for 2060 Chiron because the mass needed to be redone for the higher Spitzer diameter. I also felt it was a good round number and would favor smaller diameters (with a density of 2) for Chiron as well. But it is/was just a guess. I could have as easily gone with a density of 2. But if everything in the solar system had density of 2, we would not need the density or mass column and could just have radius column. I am not sure what line has you concerned. -- 20:29, 15 March 2009 (UTC)
This line: For example if a TNO is poorly assumed to have a mass of 3.59×1020 kg based on a radius of 350 km with a density of 2 g/cm³ and is later discovered to only have a radius of 175 km with a density of 1 g/cm³, the mass estimate would be only 2.24×1019 kg. 350 km radius is above the dwarf planet threshold, so I thought you didn't think the top list should include Earth comparisons. Serendipodous20:40, 15 March 2009 (UTC)[reply]
Well like we spoke about above (regarding assumed albedos and assumed densities), we need to be careful. I think we should make it as clear as possible when something is professionally estimated vs when it is just assumed. This is part of the reason I generated the key where R and M would obviuosly be given a lot of weight, where as with an object like 2007 OR10 your P is as good as we can do. My line, "Thus most provisional TNOs are not given a MEarth value to prevent from cluttering the list with too many assumptions that could be off by an order of magnitude." We could change the wording to say, "Thus caution should be taken with provisional TNOs since their assumed masses could be off by an order of magnitude." -- Kheider (talk) 20:56, 15 March 2009 (UTC)[reply]
I also picked a radius of 350km (likely above dwarf planet lower limit) and 175 km, since an object with a radius of only 175km could easily be a rubble pile. -- Kheider (talk) 21:03, 15 March 2009 (UTC)[reply]
Yes, I'm probably going to include data about Venus-Earth approaches. But if I do, I'll post a spreadsheet or files on my Google account, so you can check for typos.
About the argument that the calculations were OR. Some OR edits do consist of editors making calculations that are not straightforward, and possibly going beyond their ability level. Those are suspect. But in my edits I just got the predictions from a source, which can and should be be judged on its merits, not whether I am using it in an OR manner. And in fact, Solex matches Vitagliano's other long term predictions that are included in Wikipedia. Solex can hardly predict the positions so well at 100k+ years, and not well enough to make these predictions much closer to the present. By the way, the main uncertainty is in the incomplete modeling of the asteroid belt, so like Vitagliano I ran the simulations with and without the big three asteroids, to check for differences the asteroid belt would make. I also tried different starting positions (DE421, DE200, etc), as a check for that uncertainty.
As for whether this all is OR, I argue that using some quality program is the equivalent of getting these numbers from a peer-reviewed article or a source like the Astronomical Almanac
because it is also certified by experts to be reliable, and I am using it in its intended manner. OR is about going beyond the sources; this is just the routine uses of one Saros136 (talk) 10:07, 15 March 2009 (UTC)[reply]
Sounds like a good idea. I am not worried about OR here too much, but it is something that we need to keep in mind. See my OR conversation above (regarding assumed albedos and assumed densities.) You can run your numbers, I will check with Horizons and have Frank check with GravSim. If we work Venus the way we did Mercury, I think we will be fine. -- Kheider (talk) 15:18, 15 March 2009 (UTC)[reply]
Horizons only calculates Venus between 3000 BC and AD 3000. And they do not give close approach list for planets. Those are easy to do; get a list of distances by date and use an interpolation formula. I did it for part; the agreement is good. Saros136 (talk) 21:44, 16 March 2009 (UTC)[reply]
Hi Kheider,
I'm currently doing a lot of work on this article; I'm hoping to get it up to good article status. You've made more than a few edits there so I was wondering if you'd be interested in helping out.
I don't have admin status, so I couldn't move the page immediately: it's up for speedy deletion, so it should be moved over within a day. Iridia (talk) 05:17, 22 March 2009 (UTC)[reply]
Request for peer review for asteroid 243 Ida
Hi, I saw that you're interested in astronomy, and have some expertise in the area of featured articles. Would you be interested in reviewing 243 Ida? Wronkiew (talk) 06:24, 28 March 2009 (UTC)[reply]
Pallas image
Hi again. As you've pretty much asserted yourself as somewhat of an expert on astronomy, I was wondering if you could find a better image of Pallas. I asked on the talk page and got nothing. The one we have is good, but do you know where we could get a less depressing to look at and more educational colored image? Or do you have some idea what it would look like in true color? I'm guessing probably like Ceres or Vesta. I contacted the media director of this article about releasing these images (the detail is much better I think) but didn't get a response, though I could just take 'em a credit the page and author and that they were taken with the HST as I did with the current one. --IdLoveOne (talk) 00:50, 29 March 2009 (UTC)[reply]
You're welcome! You've really been hustling and contributing a lot, so deserve it. =)
That's a shame about the image, I'm sure there's a true color image of Pallas somewhere in the universe... Oh well. Anyway, can you find anything about its interior? I haven't been very lucky with this. --IdLoveOne (talk) 04:47, 31 March 2009 (UTC)[reply]
Would you mind please updating the dimensions, orbit info and the like per the new Ragozzine and Brown ref I added a few days ago? I'm going to get back there and incorporate the new info from that ref into the article once I've done a bit more on Nice model, but it seems a pity to leave the technical details incorrect in the meantime, and you're good on these things :) Iridia (talk) 07:19, 31 March 2009 (UTC)[reply]
Well, I kinda asked for it after finally blowing my top at Fotaun. I was hoping to woo him back into the fold but he seems to have permanently absconded. Not that I blame him. Anyway, now I have to sort through and source all of Fotaun's mass edits, as well as figure out how to fill the remaining gaps. I have the top list pretty well sorted; all that's required is filling in the blank fields. There are, however, a lot left to do. It's the lower lists I can't figure. What values should I use, do you think? Serendipodous16:22, 21 April 2009 (UTC)[reply]
Solar System
I have nominated Solar System for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Remove" the article's featured status. The instructions for the review process are here.
Rollback
I noticed that your frequently revert vandalism. To my surprise, I discovered that you do not have rollback! Would not you mind if I assign rollback bit to your account? Ruslik (talk) 19:17, 2 May 2009 (UTC)[reply]
Russ, I appreciate the offer and have considered asking for rollback, but I see myserlf as more of a Wiki-Gnome. I take more pleasure in making tweaks to the articles, then in politics (admins) or engaging wiki-trolls on a daily basis. :-) I like my edit history showing reverts as simply "rv" so that I can properly review my past edits if I wish. But I will let you know if one day I want to attack trolls for fun. Although I do enjoy occasionally making a funny edit summary that I know will make the Warriors come running. :-) -- Kheider (talk) 04:32, 3 May 2009 (UTC)[reply]
I fully agree with your NPOV-conscious addition (after all, the Gladman’s scheme is not always followed in the same Arizona book). However, the place of your ref is a bit awkward, as the Chiang’s article you quote appeared in the previous collection (Protostars and Planets, 2007) from the same renowned series (University of Arizona Space Science Series). Suggest re-ordering.Eurocommuter (talk) 13:17, 19 May 2009 (UTC)[reply]
Would you be interested in finishing that off with me? I know the job is immensely tedious but I can't do it alone, and now that Fotaun is out of the picture, I have no one to get me started. The attributes of the remaining 200km+ objects, since they're all constant and based on the assumed radius, should be pretty simple (if not easy) to finish. As for the rest I have no idea. This list will have to be filled in, reffed and checked for comprehensiveness. The asterisks will have to be converted to Ref_label format. Before Fotaun went off in a huff (or before I scared him off, not sure which), he seemed to be intent on making the list comprehensive for objects above 50km in radius. I have no idea if he succeeded. Serendipodous20:36, 25 June 2009 (UTC)[reply]
I just finished the 200+ sortable table, so at least this page is, to a certain extent, useful. Do you have any ideas on where I could go to finish and cite this monster? Serendipodous11:01, 1 October 2009 (UTC)[reply]
You mean cite the volume, mass, gravity or just cite the diameter? I think we can only cite the diameters and for a lot of the KBOs we are obviously using assumed values. I think the IRAS values (currently ref 13) and a generic JPLDATA call might be the best we can do. For the volume, mass, and gravity of the poorly known objects we can only let people known that generic internal wiki formulas were used. -- Kheider (talk) 12:00, 4 October 2009 (UTC)[reply]
Problem is that beyond the 200km radius boundary, we can't be certain we are dealing with spheres, so calculating mass from diameter is risky. I don't know what to do but it seems a bit haphazard leaving the lower lists so riddled with gaps. Do you think this list could ever be featured, as the Solar System FT demands? Serendipodous12:34, 4 October 2009 (UTC)[reply]
Spheres more accurate? Most of the KBOs are just best guesses at their diameters (within a factor of 2). I suspect the "spherical calculations" for the non-spherical asteroids are more accurate since the diameters are generally better known. The article could only be featured with the proper disclaimers about the lack of knowledge of these small bodies. I don't think anyone has ever attempted such a comprehensive list. -- Kheider (talk) 08:20, 5 October 2009 (UTC)[reply]
50000 Quaoar
Truly sorry, I think I was a bit too bold in using AutoEd. I guess the error came from removing a self-reference within the article. Thanks for the warning Dr. Breznjev (talk) 19:14, 16 July 2009 (UTC)[reply]
Well, this is another example why I should be extra careful when editing scientific articles with mathematical or astronomical subjects. In the mean time, I have repaired another mistake. Thank you! Dr. Breznjev (talk) 19:28, 16 July 2009 (UTC)[reply]
I found this page, which contains additional information, but I was unable to find anything else. The Science's articles about V1&2 encounters with Jupiter do not have this image. The only way to discover the truth may be to ask Palomar directly. Ruslik_Zero09:59, 11 August 2009 (UTC)[reply]
Does that happen often? I came back this morning to find the page slapped with an autoprotect. Seemed a bit rough - he'd done nothing to that page that was unconstructive. --Iridia (talk) 03:24, 13 August 2009 (UTC)[reply]
Hi! Well, afair this image comes from en.wikipedia, I just moved it to Commons. In my opinion the best way is to contact with Scott Sheppard via mail from his website and take permission for this and other images and send it to OTRS. I don't have any 'astronomic' experience, so if you can contact with Mr. Sheppard I will be grateful :). Yarl✉10:53, 13 August 2009 (UTC)[reply]
While adding an external link (to my website describing precovery astrometry) for this object, I took the opportunity to
correct the upcoming perihelion date. You reverted it, saying that the "Orbit not determined well enough to pindown the exact day". As a result of my precovery work, involving the finding and measuring of images from nine plates at seven
oppositions back to 1980, this TNO has now been observed for a total of 28 years, and the orbit is very well known and the
date of perihelion is known to within one day. I even got the opportunity to account for planetary perturbations, so that
my perihelion date of November 1, 2096, is based on osculating elements from the same date. Just thought you might want
to know the background to my edit..
Lowe4091 (talk) 23:14, 23 August 2009 (UTC)[reply]
I have a reduced HST image of Orcus/Vanth lying around on my hard drive. Though figuring out which orbit I got it from might be a bit more tricky. HST data is fine to go on Wikicommons, yes? Iridia (talk) 22:58, 16 November 2009 (UTC)[reply]
Apropos your quick repost to my discussion on the apparent visual magnitude for Mercury.
You are at liberty to do the calculations and to ignore the extremes, as you put it.
The following may be of interest.
John C. Vetterlein
J. Br. Astron. Assoc. 116, 5, 2006:
It is not generally appreciated just how bright Mercury appears when close to superior conjunction. It is interesting to compare
the two events this year when Mercury and Venus both reach superior conjunction. On 2006 May 18, Mercury was at magnitude
–2.3. When compared to the data for Venus at superior conjunction on October 27, we find that the surface brightness per unit area will be almost identical for both planets. Put another way, Mercury would be at magnitude –3.7 if it had the same apparent diameter as Venus. (Venus on October 27 will be at magnitude –3.9.) There are times in fact when the surface brightness per unit area for Mercury outdoes Venus herself. Naturally, when Mercury is close to inferior conjunction it is both faint and too close to the Sun to even attempt an observation.
JPL Horizons shows Mercury at apmag –2.4 on 2006-May-18 04:45UT, but of course Mercury is only 0.79° from the magnitude –26 Sun. When Mercury is 4° from the Sun it is only mag –1.9. Perhaps we should change the range to show "–2.3 to 5.7" (May 28 2002) -- Kheider (talk) 18:41, 26 November 2009 (UTC)[reply]
There's a clarify tag in the Mass section of Halley's infobox, but I'm not entirely clear what it's saying. Is it saying that we have no idea at all what Halley's mass is? Since this falls under your jurisdiction I thought I'd ask you before making any further assumptions. Serendipodous22:02, 26 November 2009 (UTC)[reply]
The value 2.2×1014 kg is indeed mentioned in Cevolani, 1987. It comes from D.W. HUGHES, Mort. Not. R. Astron. Soc., 213, 103 (1985). The estimated core diameter is 9.4 km. Ruslik_Zero06:24, 27 November 2009 (UTC)[reply]
Good. A diameter of 9.4km with a density 0.5 g/cm³ would generate their mass of ~2.17×1014kg. I am glad to see my estimate is not way out of line. Obviously we want to use their numbers. Though I do have to wonder why NASA quotes a diameter of 11. -- Kheider (talk) 07:31, 27 November 2009 (UTC)[reply]
I would go: Sedna (biggest candidate in theory), 2007 OR10 (is very red and does have a bright absmag (H)), Quaoar (about twice the mass of Orcus), Orcus (the possible double dwarf), and then use the same generic method the IAU uses: bright absmag (H). We do not normally know the size (HST direct measurement, Spitzer), mass (need a moon), or how much fresh ice is on a surface. So absmag (H) is probably the best generic test. Though I doubt this really helps you much. -- Kheider (talk) 20:53, 3 December 2009 (UTC)[reply]
terrestrial planet
I like the idea of having a name for "real" moons like ours, which are actual worlds, as opposed to the bits of rubble orbiting, say, Mars. But why "terrestrial"? We didn't consider Pluto to be a terrestrial planet, so why should Triton be considered a terrestrial satellite? kwami (talk) 08:37, 21 December 2009 (UTC)[reply]
Well it is somewhat of first draft. I included Triton simply because it is often compared to Pluto, and Pluto is often compared to Earth (more so than it would be compared to a gas giant.) I thought the image of Triton showing an active atmopshere was some what terrestrial-like. But I am open to other ideas. Both Pluto and Triton are dense enough that they are likely made mostly of rock. Unlike Ceres, in literature Pluto is seldom compared to the Earth because of where Pluto is located. I wanted to give the planet definition issues some coverage without picking sides. I suppose the section could be called "Terrestrial-like satellites", but I don't think that would come across any different. I am open to ideas. -- Kheider (talk) 08:56, 21 December 2009 (UTC)[reply]
Kheider, I hate having to do this, but I've removed the text for now until it can be further discussed. Having looked at the forum you referenced, it really felt as if Wikipedia was giving the concept far more weight than the discussions actually warranted. Even though it was Alan Stern mentioning the idea, we've no indication that he would support what was written. For all we know, it was just some people tossing around ideas. That aside, if we can track down more material to support the idea, it might well make for an interesting addition. Thoughts? --Ckatzchatspy09:12, 21 December 2009 (UTC)[reply]
They're planetary satellites, except that that phrase also has the meaning of 'satellites of planets'. But they're in HE and have cleared their orbits, so apart from orbiting s.t. which is not undergoing fusion, they fit the def for planets. Is there any way of saying 'planetary satellite' that wouldn't be understood as having the second meaning? (I suppose "planet-like satellites", but I don't like that phrasing; it seems more confusing somehow than illuminating.) kwami (talk) 09:16, 21 December 2009 (UTC)[reply]
Happy 2010! We have not talked much, but I am always amazed how often I find your edits among the vasts sea of objects in space! Have a great year. Fotaun (talk) 15:23, 1 January 2010 (UTC)[reply]
I can't seem to avoid getting into scraps over that bloody article. I just got warned for edit warring on that page. I dunno. I sometimes wish more people had the page on their watchlists so I didn't have to wade in at nearly every opportunity, but I can't shake the feeling that *gulp* maybe HarryAlffa had a point. Serendipodous13:14, 30 January 2010 (UTC)[reply]
I can see it both ways. You are very protective and I can see how people (especially newbies) would be intimidated by quick reverts. I would not say Harry was right, because he was never right without insulting everyone's intelligence. He got a kick out of trying to suggest to people that they are fracking idiots while trying to appear politically correct. My concern would always be for the Fotaun's of the group. Though a few kind words to Fotaun wouldn't hurt reminding him you are sorry if you come across as overprotective. Just my 2 cents. -- Kheider (talk) 01:19, 31 January 2010 (UTC)[reply]
For comets, such as 42P/Neujmin, with aphelion near 6AU or further, I think it is better to display Saturns orbit. The only way to display Saturns orbit is to use the ;view=Far parameter. -- Kheider (talk) 17:20, 1 March 2010 (UTC)[reply]
Hello. Your account has been granted the "reviewer" userright, allowing you to review other users' edits on certain flagged pages. Pending changes, also known as flagged protection, will be commencing a two-month trial at approximately 23:00, 2010 June 15 (UTC).
Reviewers can review edits made by users who are not autoconfirmed to articles placed under flagged protection. Flagged protection is applied to only a small number of articles, similarly to how semi-protection is applied but in a more controlled way for the trial.
When reviewing, edits should be accepted if they are not obvious vandalism or BLP violations, and not clearly problematic in light of the reason given for protection (see Wikipedia:Reviewing process). More detailed documentation and guidelines can be found here.
Thanks for doing that. My preference was to have the data presented in the most prominent place, but I was not sure if it was appropriate to undo the other user moving it. James McBride (talk) 04:26, 19 June 2010 (UTC)[reply]
Per your latest edit, AFAIK, H.E. does not require differentiation, even if differentiation predicates H.E. S.t. Ceres' size may very well be differentiated, but AFAIK we have no evidence for it. — kwami (talk) 09:52, 22 July 2010 (UTC)[reply]
God I hope Dawn is extended to a Pallas flyby! Even if they get only one image (but better still if the craft is deflected!) — kwami (talk) 10:57, 22 July 2010 (UTC)[reply]
I was wondering, I don't have the tools to do it right, but do you think you could crop and brush up the corner of the Solar System image so that it shows only the orbit of Sedna? The other three screens are not really necessary and they make it hard to see. Thanks.
PS. Purely a formality (I was going to do it anyway), but I should ask you whether you wish to be listed as a co-nominator should I take Sedna to FAC. Serendipodous20:13, 22 July 2010 (UTC)[reply]
Sure thing. :) BTW, do you think Orcus and Quaoar could be featured? Or do we need to wait until there's more data?
Sedna Mass
Your figures (I think they're your figures- they usually are :) ) for Sedna's mass are based on assumed densities. I was wondering why you selected those densities to assume? Serendipodous18:12, 25 July 2010 (UTC)[reply]
The mass range is mine (small diameter+Tethys (moon) density) to (large body+Eris style density): 8.3×1020–7.0×1021 kg : Radius of 590 km and density of 0.97 = 8.3×1020 kg mass. Radius of 800 km and density of 2.3 = 4.9×1021 kg mass (0.05–0.29 Eris). But the generically listed density 2.0 appears to be the one-size-fits-all large body KBO assumption that Wiki uses and has been there since my first edit of the article on 1 November 2006. The generic density of 2.0 appears to have been added 23:51, 27 January 2005. -- Kheider (talk) 19:22, 25 July 2010 (UTC)[reply]
That decision was ridiculous. The deleter appeared to have no comprehension of the issues involved, this has survived previous objections, and there was no community discussion--censorship by bureaucrats. I've restored the image: let's have a real IfD discussion if we're gonna have one. (Under BRD, he made the bold decision to delete, I reverted, now he needs to discuss.) — kwami (talk) 09:13, 6 August 2010 (UTC)[reply]
We could also create a lower-resolution version without any real loss of data. Sometimes lo-res images are accepted where full-res is not. But I don't see how this is an issue any more now than it was when the Pluto image was up for debate. — kwami (talk) 09:20, 6 August 2010 (UTC)[reply]
The results may be preliminary, but even Mike's website seems to agree that Eris could easily be on the low end of the various different size estimates, and by definition that would make Eris somewhat more dense than originally estimated. And if a regular editor did not make modest size and density edits, I suspect an anon-IP would would rip Eris up and down since this is a hot topic for Pluto huggers.. -- 15:43, 9 November 2010 (UTC)
I want to clarify that the absolute magnitude of Ixion in the V-band is 3.86 and in the R-band 3.25 (See this or this). JPL unfortunately often confuses them. Ruslik_Zero19:26, 1 December 2010 (UTC)[reply]
Different values for the magnitude of 2003 AZ84 are probably related to its photometric variability. According to Ortiz the magnitude varies by ±0.1. For instance, Perna reports 3.77 for the V-band magnitude. On the other hand, the JPL value of 4.0 is probably an outlier. Ruslik_Zero19:51, 7 December 2010 (UTC)[reply]
What does this have to do with an astronomical unit?
The astronomical unit is a measure of the distance between the Earth and the Sun that serves the basis for parallax measurements and many solar system measurements. What basis do you have for claiming that secular variations of planetary orbits have to do with this particular distance? Please make a mathematical argument or a cited argument from the literature. jps (talk) 19:33, 22 December 2010 (UTC)[reply]
Of course secular variations are not a fringe theory. What is a fringe theory is suggesting that it is affecting our current measurements of the astronomical unit which is the implied coatrack that is going on with Kurtan's edit. jps (talk) 20:56, 22 December 2010 (UTC)[reply]
On 21 February 2011, Did you know? was updated with a fact from the article Tyche (planet), which you created or substantially expanded. The fact was ... that in 1999, a giant planet was hypothesized to exist in the outer Oort cloud of the solar system, but most astronomers are skeptical of its existence? You are welcome to check how many hits the article got while on the front page (here's how, quick check) and add it to DYKSTATS if it got over 5,000. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
BTW, am I to assume by your recent activity that you now oppose the future mergence of Tyche (planet)? If you feel it's important enough for its own page, that's OK, just clarify on the talk page. Serendipodous23:38, 22 February 2011 (UTC)[reply]
Comet Elenin
How do you set epoch 2020-Jan-01 at JPL page for the comet Elenin. Also, I see you reverted or edited many of my edits that came from JPL page for Elenin. Are you implying they are all incorrect? Is there a website that gives more accurate values? Thanks Wildespace (talk) 15:35, 25 February 2011 (UTC)[reply]
Thank you for inquiring about my revert. The JPL Small-Body Database Browser gives us an unperturbed two-body solution to the comets orbit. The osculating perihelion eccentricity is never a good indication whether a comet leaves the solar system since often the osculating eccentricity is larger than 1 in the inner solar system, but the future (or proper) eccentricity is smaller than one when it gets beyond the influence of the planets. For example, the JPL Small-Body Database Browser shows Comet McNaught (C/2006 P1) as having no orbital period since the perihelic eccentricity is greater than 1. But it is known that Comet McNaught has a ~100,000 period (~92,600 using the most recent data). Two other comets that the "unperturbed two-body solution" JPL small body database gets grossly wrong include Comet Lulin and C/2000 W1.
The only way to get a perturbed orbit is to integrate the orbit to the point the comet is beyond the planets, ie: I choose 2020 as a nice round number. For objects at such high eccentricity, the Suns barycentric coordinates are more stable than heliocentric coordinates. To reproduce these barycentric osculating orbital elements for 2020:
Change "Ephemeris Type" to Orbital Elements (3rd option at the bottom) and click "Use Selection Above".
Change "Center" to @0 to select the Solar System Barycenter (SSB).
Change "Time Span" to 2011-01-01 through 2020-01-01 with a step size of 1 year. Click "Use Specified Times".
Click "Generate Ephemeris".
You will find for the epoch 2020-Jan-01, that the semi-major axis (A) is 459 AU, AD (Apoapsis distance) = 919 AU, and the period is 3.6*10^6/365.25=9,856 yrs. -- Kheider (talk) 16:12, 25 February 2011 (UTC)[reply]
Argh. That was pretty bad. I knew I wouldn't be able to talk about myself without sounding like a total douche. It never occurs to me until the moment that I can't think of the right things to say in those situations. Serendipodous00:41, 7 March 2011 (UTC)[reply]
I'm not really any better at replying to a Q&A. When I wrote, "Since my writing skills are not always the best, I frequently add numbers and references to articles and then allow more experienced writers to giving the article a more encyclopedic feel", I was referring to more skilled editors such as yourself. I always have trouble keeping a continuous flow to my writings. I also hope that I responded to the format correctly. -- Kheider (talk) 15:44, 7 March 2011 (UTC)[reply]
I learnt that "they are probably both correct; the first [Mare Foecunditatis] is classical Latin, the other one [Mare Fecunditatis] probably late vulgar Latin...".
Hello... FYI, you might want to check out Wikipedia:Credo accounts as you're active on FAs and GAs. I mentioned this to Serendipodous a few days ago but went offline before I could post here. Sorry for the delay. Cheers. --Ckatzchatspy09:28, 28 March 2011 (UTC)[reply]
You really should add something about the conspiracy theories surrounding the comet's arrival. Otherwise people are just going to keep rewriting it forever. I would suggest Ask an Astrobiologist would be a good place to start for debunking tools. Poor David Morrison deals with the woo woos up close. You belong to Elenin's forum, right? You might ask him how he feels that some assume that he doesn't exist and that his name is in fact a code for ELE-NIN, or "NIN's Extinction Level Event". That would give both you and me a killer usable quote.Serendipodous12:32, 3 April 2011 (UTC)[reply]
So far I have left the comet article to the known facts about the comet. I think the Nibiru article can better handle the handful of people that promote Elenin as Nibiru. Perhaps it is time to think about getting comet back up to FA status? -- Kheider (talk) 17:13, 5 April 2011 (UTC)[reply]
Hi. C/2002 V1 (NEAT)first arrived at a distance that was closer to the Sun than the asteroid belt in September 2002. However it was not discovered until November. Thus this refers to the comet's early orbit rather than perihelion. Thanks. ~AH1(discuss!)19:35, 12 April 2011 (UTC)[reply]
Are astronomers 100% certain the transit of Earth from Mars will happen or is there a slight possibility that the course of the orbit will be put of an event in space? Pass a Methodtalk16:00, 1 August 2011 (UTC)[reply]
Les Golden
The ball is definitely rolling on the Les Golden article now with its coi/notability problems. I didn't say anything before, but I did wonder why he called you since I didn't see anywhere that you had edited the article. But then I figured it wasn't my place to pry into other people's personal lives. I guess maybe it was because of your interest in astronomy and that's what he got a degree in? Anyway, now I'm off to clean up his mess. SQGibbon (talk) 03:43, 1 September 2011 (UTC)[reply]
Snow White
This illustration credits NASA with the "red Snow White" image. Since all it is is a tinted version of an image created on Wikipedia, I say if they credit NASA, we can too. Do you have the know-how to paste it into the main picture? Serendipodous13:16, 7 September 2011 (UTC)[reply]
Dwarf planets - what is the standard for Wikipedia labelling an object as a DP?
Hi, could I ask for your input at Talk:Dwarf planet to help resolve this dispute? Whichever way it ends up, at least we'd have a consensus. I find Kwami's continual insistence on inserting his text very frustrating, especially in light of the fact it is under discussion and contested. Cheers. --Ckatzchatspy17:03, 20 September 2011 (UTC)[reply]
2004 BX159
I started an article about 2004 BX159 because it seemed important (1200 meters, 98,000 megatons, close- approach; well, seemed important to me, anyway). Now I'm not so sure, because the JPL small-body and NEO Close Approach data do not seem consistent. The former indicates eccentricity .38, perihelion 1.5AU, and semi-major axis 2.4AU, which would seem to put the asteroid well outside Earth orbit; OTOH the latter shows a close approach with distance 7.6 Earth radii (.0003AU) and a width of 1060 radii (.046 AU). Trying to visualize that, it just doesn't seem reasonable that (with the given perihelion and semi-major figures) the asteroid could get that close to Earth. I would like suggestions on whether to just request delete for the page; or if not, where I might place a link to the page so it is no longer orphaned. (I'm asking you because of your work on YU55.) CoyneTtalk04:09, 14 October 2011 (UTC)[reply]
Your original edits were very helpful in restoring neutrality to the article Nemesis (hypothetical star) and are to be commended.
However now you are starting to exhibit bias in the other direction. Please remember that Wikipedia is not for pushing your personal opinions. You should be able to handle it when someone posts a source that is contrary to what you believe, as long as the source is valid. It cab be helpful to learn the difference between manipulation or campaigning and unbiased journalistic neutrality.
Warning: Your revision notes in "History" are also becoming over-emotional-- posting long lines of exclamation points after a revert (!!!!!!!!!!!!!!!!!!!!!!!!!) are frowned upon in Wikipedia and can get you blocked or banned.
I am giving you fair warning that I will report you if you don't calm your self down and remember to tolerate all citable facts, whether or not you personally feel they forward your own personal views. --69.171.160.51 (talk) 15:58, 22 October 2011 (UTC)[reply]
Please provide a citation when adding new material, you spend too much time claiming you will add a citation when you "find time" because you are "busy now, sorry". That is not proper and will quickly get you reverted for OR, SYNTH, weasel words, or fringe theories. You obviously had enough time to complain on my talk page. I used the "!!!" marks to clearly mark my edit so that I could more easily file a complaint against you (IP: 69.171.160) -- Kheider (talk) 16:18, 22 October 2011 (UTC)[reply]
The reason the "{{citation needed}}" notation is allowable in Wikipedia (and the reason the code works for posting such a notation), is because Wikipedia does allow time (up to a month) to then go and find the citation.
You should know that when a controversial/fringe article is being edited that you should provide a reference for your statements so that you are not reverted for OR/fringe theories. -- Kheider (talk) 16:46, 22 October 2011 (UTC)[reply]
Please Note Also: If the "ancient passing non-companion star theory" is acceptable in the article (also as yet unproven) then so also is the Tyche theory (both should be there, because both relate to the credibility of the Nemesis (hypothetical star) theory).
You can't let one theory in and then take the other one out, just because you like one and not the other. You originally did help to make the article more neutral, but now you appear to be pushing your own opinions, exhibiting bias yourself (only theories that support your opinions are allowed in the article, but those theories that don't support your opinons are not). You might also want to review this article, about the word "Unbiased". --69.171.160.51 (talk) 16:33, 22 October 2011 (UTC)[reply]
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Hi. My editing of Pluto has been questioned (on my talk page), and I referred to your comment of some weeks back. I'd just moved the inline references to the {{reflist}} and have also started using proper lists in the infobox. Comment welcome, although I have to go out, soon. Tycho Magnetic Anomaly-1 (talk) 23:46, 1 December 2011 (UTC)[reply]
Trust me, so far I am just watching from a distance. I am just curious how the fear mongering will try to twist Wikipedia's rules to suggest anything about YU55 was truly strange. -- Kheider (talk) 22:46, 14 December 2011 (UTC)[reply]
Hi. You added a statement that Lovejoy is the brightest (EDIT: Sungrazer) comet ever observed by the SOHO instruments. Where did you get that information from?? The article is now somewhat self-contradictory, stating simultaneously that C/2006 P1 was brighter by 2 magnitudes (it very likely was brighter judging by images) and C/2002 V1 seemed brighter as well, even as it recorded a lower visual magnitude. As a Kreutz Sungrazer, Lovejoy's properties may be different. However, it looks much smaller than those other comets. Please back up any information using citations. Thanks. ~AH1(discuss!)20:01, 17 December 2011 (UTC)[reply]
The quick answer is that neither C/2006 P1 (McNaught,) or C/2002 V1 (NEAT) were sungrazers, they just happened to pass near the Sun (in the sky). NEAT peaked at only -0.5. I also believe SOHO used custom exposures and filters for imaging C/2011 W3. -- Kheider (talk) 20:34, 17 December 2011 (UTC)[reply]
Makemake
Come on, Kheider. No reason to mock. Sheppard put Makemake on par with the Brown four, Tancredi notes that only the three Sheppard accepts unequivocally are actually known rather than estimated to be DPs, and even the IAU has set out provisions for the case that they turn out not to be DPs. Our individual articles for these, as well as the other Tancredi twelve, reflect the degree of certainty in their lead sentences, except for Makemake & Haumea. I'm sure you can come up with a better defense for your position than UFOs. — kwami (talk) 02:05, 6 January 2012 (UTC)[reply]
Looking at your edits [5][6] you are clearly mocking the IAU, and thus Wikipedia. My edit summary was mocking UFOs because you do not have a reliable source that Makemake is not massive enough to qualify as a dp. At least I am not making a joke of a Featured Article. -- Kheider (talk) 12:16, 6 January 2012 (UTC)[reply]
*sigh* Kheider, you're intelligent. I find it very difficult to believe that you believe the stuff that you say. You are obviously also literate, so I can't explain your repeated inability to understand what I write.
I am not mocking the IAU, and if I were, what has that to do with WP? There is no rational connection. I have no problem with the IAU, actually; the problem is that they haven't done anything in 3 years, and I do not accept as you seem to that scientific conclusions are determined by committee, and must be put on hold when the committee is out of session.
I never claimed that Makemake was not massive enough to be a DP. You've got to know by now that is not the issue, don't you? The issue is that Makemake is not known to be a DP. That's all. You've seen the refs: Tancredi, Sheppard, the IAU itself. Are you honestly saying that Sheppard's motivation is to mock the IAU?
(And, of course, you are unable to defend against that same argument: do you have any ref that Sedna or OR10 are not massive enough to be DPs?)
BTW, your "scientists are not 100% certain" comment certainly strikes me as mocking. I can think of no good-faith reason for writing something like that.
I do not understand why you are so resistant to following sources. In science there are almost always going to be a variety of opinions, and it is our responsibility to reflect them. According to Tancredi, now a bit dated, there are 12 demonstrable DPs. According to Sheppard, there are 3. According to Brown, there are 9. It is the refusal to follow such sources that IMO is making a mockery of WP, and endangering the FA status of these articles. — kwami (talk) 12:28, 6 January 2012 (UTC)[reply]
Many of your edits seem to use synthesis because (as you admitted above), you are not happy that the IAU has not acted on any additional dp candidates. I doubt the IAU will do very much until we known more about Sedna and 2007 OR10. We still know nether their proper size, much less anything about their proper mass. Are Sedna and OR10 probably dps, of course. But Wikipedia should not declare them as dps when we know so little about them. Science does not require a Wikipedia-imposed-timeline. -- Kheider (talk) 13:04, 6 January 2012 (UTC)[reply]
As for your reference "Plutoid chosen as name for Solar System objects like Pluto", it states it very clearly that these "very bright absmag<1" objects are listed as dwarf planets. It then states they will be removed "If further investigations show that the object is not massive enough". We have no references that Makemake is not massive enough and we KNOW the mass of Haumea. -- Kheider (talk) 13:04, 6 January 2012 (UTC)[reply]
Please explain how following those references is synthesis. I honestly do not understand: The distinction pointed out by Tancredi and Sheppard is between demonstrated HE (3 bodies) and calculated HE (the rest). I see no synth in reporting that; rather, I see an effort to reflect our sources, which is essential to any WP article. As for being unhappy with the IAU, I expect WP to keep up to date with the field. You seem to think that we should go on holiday until the committee reconvenes, as if that were what drives science. You yourself have said that IAU acceptance is not part of the definition of a DP, yet that's the criterion you insist on.
Yes, H<1 objects are assigned to the committee in charge of DPs for naming. But as the IAU acknowledges, and you quote, naming s.t. as a DP does not make it a DP. What makes it a DP is being in HE, and that is not known. As for your last point, we have no references that Senda and OR10 are not massive enough either, and we KNOW the masses of Quaoar and Orcus, so your argument falls apart. And to your inevitable response that Quaoar and Orcus are less massive than Haumea, Haumea is less massive than Pluto. So what? The minimum mass for a DP has not been established, so your argument is OR as well as synth. And in any case, Quaoar is more massive than Ceres, so if we're going to engage in that kind of argument, Quaoar would qualify.
The responsible approach is to follow the sources. For 3, the sources are unanimous. For these two, there's a clear majority, but with some reservations. For the rest, we have good sources (Brown, Sheppard, others, which equate them with these two), but not IAU acceptance. I really do not understand how saying that could be contentious. — kwami (talk) 14:31, 6 January 2012 (UTC)[reply]
Any object with an abs mag < 1 will be a dwarf-planet beyond any reasonable doubt because it will be almost impossible for such a body to be less than 800 km in diameter. The data showing Sedna and OR10 as dps is not as solid as the data showing Haumea (bright+known mass) and Makemake (bright+size fairly well determined @ 1400km). -- Kheider (talk) 14:54, 6 January 2012 (UTC)[reply]
Oh, I agree completely. But presenting this as The One Truth is OR. We have one source, the IAU, drawing the line at 5. We have another, Sheppard, drawing it at 3. We have yet another, Brown, drawing it at 9, and Tancredi at 12. All of them are reasonable, but all are arbitrary—apart from Sheppard, who draws the line at established HE. If we're to be honest to the scientific literature, which we have an obligation to be, then we need to report the Sheppard 3, the IAU 5, and the Brown 9. (Tancredi is a bit dated, but we could include them too.) — kwami (talk) 15:15, 6 January 2012 (UTC)[reply]
I will have to think about what "middle ground" I want there. If Sue Bowler is not an astronomer, I am not sure that that is a good source. -- Kheider (talk)
If true, we might just need to correct the name of the author. I don't have access to the entire article. But if it's just an editorial by a non-astronomer, then I agree that it wouldn't be a good source. — kwami (talk) 20:12, 6 January 2012 (UTC)[reply]
Yeah, it's probably not a good source, based on what I can see. I've found another version that's worded almost the same, and it a news summary of one of Brown's papers. — kwami (talk) 20:48, 6 January 2012 (UTC)[reply]
Sedna
Your recent edit to Sedna and Ckatz' revision seem good to me. The only quibble I have offhand is priority. In order of importance/interest, I'd say the top by far is that this is the most distant significant body known. That's already partly covered by the first line, though I think we could make it more explicit (in a couple words, since we cover it in the 2nd paragraph.) The 2nd greatest interest is that it's a likely DP (though that's of practically no true importance, as DP is not a particularly meaningful classification). I would therefore want to move that statement up a line. Surface composition is a distant 3rd, or maybe 4th. Maybe move up 'reddest' too, as it's more accessible than "tholins" to most of our audience: Farthest – likely DP – reddest – composition. Does that seem reasonable? — kwami (talk) 21:29, 13 January 2012 (UTC)[reply]
I kind of like what you are saying, but I am not sure I like the look of having 5 references tags buried in the middle section of the lead paragraph. It seems cleaner and less tacky with the tags located at the end of the paragraph. -- Kheider (talk) 22:08, 13 January 2012 (UTC)[reply]
Well, the only reason for the tags in the lead is the edit warring. There's no need for them in a well-developed article. Ideally, a lead summarizes the text, and only the text is referenced. If you have to ref the lead, there's something wrong in the structure of the article. So if we fit the refs in the text, we can say what we want in the lead without cluttering it up. There's already a classification section; they should fit there. I think if you make the changes, Ckatz will accept it. And wording in the text is less contentious, because it's not so in-your-face, and also easier, because there's little need for brevity.
Either that, or remove the composition from the lead. It's not the kind of thing we bother with in most articles. (Of all the things to say about Sedna, are surface methane and tholins really of primary interest, when we already know it's a TNO?) A lot of these tidbits get left in the lead from when we only knew those few tidbits and the article was a stub; the stub evolves directly into the lead rather than a lead ever being crafted for the expanded text. — kwami (talk) 22:34, 13 January 2012 (UTC)[reply]
Kheider, could you explain to Ruslik that comments belong in the comment section, not plastered all over the quotations? Esp. not things like "you're lying" or "you're wrong": If he thinks he knows more than the authors of these articles, he should present new refs that back him up, and discuss them in the discussion section. The whole point of having a separate quotes section is so that we can all refer to them without them getting lost in reams of debate. — kwami (talk) 15:47, 15 January 2012 (UTC)[reply]
It doesn't sound like it's a well defined concept regardless. What about saying it's "typically" so? There are plenty of cases where Pluto–Charon are said to be a double because Charon is so large in comparison, or that Earth–Luna are not because the barycentre is within the Earth, etc, indicating that this is people's conception of what a double would be. — kwami (talk) 15:01, 11 February 2012 (UTC)[reply]
Yes, but there are those who do say Earth–Luna are a double planet. AFAIK, no-one proposes that Neptune–Triton are a double planet, except probably Stern, and it would seem he's very much in the minority. In cases where there is no fixed definition, we do cover typical usage of terms. — kwami (talk) 15:49, 11 February 2012 (UTC)[reply]
2011 AG5
I added "For comparison, the meteorite that excavated Meteor Crater, which is 1.2 km ( .74 mi ) wide, was about 50 meters across.", because as a non expert I found it hard to figure out what the magnitude of the damage would be if 2011 AG5 were to hit earth ( a gross estimate anyway ). Could you reconsider reverting or suggest a better comparison? Stating the kinetic energy in megatons would be nice, but I haven't found such data and it would still be much more technical than crater size. -- Carel.jonkhout (talk) 04:41, 7 March 2012 (UTC)[reply]
Given that a crater is a function of the composition/density of the impactor, the impact angle/speed, and the composition of the impact zone, I think it might be more accurate to list a generic/referenced kinetic energy estimate in megatons of TNT. 2011 AG5 (140 meters) is estimated at 100 megatons of TNT and 2012 DA14 (45 meters) is estimated at 2.3 megatons of TNT. -- Kheider (talk) 12:07, 7 March 2012 (UTC)[reply]
The section deals with cultural references related to the 2012 phenomenon. The fact that the show was released in 2012 is hardly sufficient evidence of a nexus between the two. Granted, I think it's clear they are capitalizing on the 2012 fervor because of all the talk of end-times, but you'll need to find a citation linking the two. Perhaps there's an episode specifically dealing with doomsday preppers who think the world will end in 2012 based on the Mayan calendar?JoelWhy (talk) 14:12, 5 April 2012 (UTC)[reply]
You recently said "third revert of byelf2007". That's not the case. You did only a second one.
The first time I got reverted I said "most" instead of "the vast majority of", so while I've been reverted three times recently, these were concerning two different types of edits. Byelf2007 (talk) 11 April 2012
For the record: 1234 I am not saying anyone should invoke the The three-revert rule, but it does seem like needless weasel words/redundancy when there is an expanded explanation in the same paragraph. No worries, besides I see you also took it to the talk page. I over document "multi-revert edit summaries" since I spend a lot of time editing articles that contain pseudoscience. -- Kheider (talk) 10:20, 11 April 2012 (UTC)[reply]
I think just mentioning this on my talk page gives credit enough. Besides I think most of the general public is going to better associate this event with the Lyrids of 2012 than as the Sutter's Mill meteorite, even though the meteoroid likely had nothing to do with Thatcher's comet. Thus some content should be kept in both articles. -- Kheider (talk) 15:24, 29 April 2012 (UTC)[reply]
Mu Canis Majoris (Bayer designation), is 18 CMA (Flamsteed number), HR 2593 (Bright star catalogue), and HD 51250 (Henry Draper catalogue). This is why if you are searching for a star in SIMBAD - it's best to use the HR designation, and not the Bayer designation. HR designation will work every time. Look at a map of the constellation Canis Major. Mu Canis Majoris is the dog's eye, between the three stars that mark the head. You can see it on wikisky. Benkenobi18 (talk) 04:48, 3 June 2012 (UTC)[reply]
Pluto image
Hello there, while Fair Use images consists on the usage of medium to low resolution images, images copyright free or with free licenses do not limits the usage of high resolution images, images with low resolution have a inhuman aspect and does not pass a substantial or near real impression, this is why we can count on artistic impression, to give the reader the idea (based on a actual image, not randomly based) of the rendered planet if we could see it with naked eyes. Thanks in advance. Eduemoni↑talk↓15:32, 13 June 2012 (UTC)[reply]
I reverted your image from the Pluto article because your image shows the same Hubble data as the official Hubble rotating image in the Infobox. Your image also added no useful content to the "Orbit and rotation" section of a featured article. As most people will not click on a article thumbnail, it does not really matter that your artists impression has a Celestia equivalent resolution of 1,920 × 1,200. Commons has other official high resolution images such as File:Pluto-map-hs-2010-06-b90.jpg that are also not needed in the article. I will probably revert the image again. -- Kheider (talk) 16:01, 13 June 2012 (UTC)[reply]
S/2011 P 1
Excuse me, but what world do you live in? I don't see any consensus there. A consensus would be everyone supporting the move, yet everyone is NOT doing that and there are many Oppose posts. Trying to gag people who go against your agenda is very shallow and it's quite obvious you're on a power trip. You started editing this page from P1 just 4 days ago. What consensus did you have for that? Where was the discussion? Because I surely couldn't find it....
Sorry, but until there is a clear consensus and if the page is moved to 134340, I will continue to edit the article as it is reflected in the article name. — Preceding unsigned comment added by 98.238.183.175 (talk) 06:41, 18 July 2012 (UTC)[reply]
It is somewhat odd that the view count is spiking every other day. If the wiki counter is being deliberately manipulated, is there anything we can do about it? Serendipodous06:45, 3 September 2012 (UTC)[reply]
Given that it has spiked from 10k views a day to 118k, 675k, 95k, and 1.2 million, I suspect IP 150.126.x.x and his friends at GLP are causing the spike. Nothing special in the news has occurred to cause the spike and IP 150 even predicts the spikes before they occur. -- Kheider (talk) 11:04, 3 September 2012 (UTC)[reply]
I do not think there is enough material to take it to ANI yet. But he will need to be watched since he appears to be some kind of fringe editor promoting an agenda. He has also made some weird edits at Coronal mass ejection with links to unreliable sources. -- Kheider (talk) 17:07, 23 September 2012 (UTC)[reply]
On 2 October 2012, Did you know? was updated with a fact from the article C/2012 S1, which you created or substantially expanded. The fact was ... that when the newly discovered comet C/2012 S1 reaches its perihelion on 28 November 2013, it may appear brighter than the full moon? The nomination discussion and review may be seen at Template:Did you know nominations/C/2012 S1. You are welcome to check how many hits the article got while on the front page (here's how, quick check) and it will be added to DYKSTATS if it got over 5,000. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
I see that you have recently added three-letter abbreviations for many well-known meteor showers. Is there a printed or reliable source for this (i.e. is this used by meteor observers) or is this your own invention? AstroLynx (talk) 14:55, 11 December 2012 (UTC)[reply]
I'm dropping you a note because you've been involved in dealing with feedback from the Article Feedback Tool. To get a better handle on the overall quality of comments now that the tool has become a more established part of the reader experience, we're undertaking a round of hand coding - basically, taking a sample of feedback and marking each piece as inappropriate, helpful, so on - and would like anyone interested in improving the tool to participate :).
You can code as many or as few pieces of feedback as you want: this page should explain how to use the system, and there is a demo here. Once you're comfortable with the task, just drop me an email at okeyeswikimedia.org and I'll set you up with an account :).
Finding sources on that topic is hard at the best of times, and now that David Morrison has officially retired from doomsday countering, I don't have an easy port of call. Serendipodous10:33, 1 January 2013 (UTC)[reply]
It should stay as a separate article. Many people still promote it on youtube. Doom will continue to be good business because fear sells. That is the nature of cosmophobia. If something does not extinguish life as we know it this week, the next event is just around the corner. -- Kheider (talk) 17:20, 6 January 2013 (UTC)[reply]
I do not see why the article needs to expand at this time. If someone wants to believe in something that scientific theory does not support and has not been seen, I am not sure there is much Wikipedia can do about it. What we might want to do is expand the section in the comet article about omens, cosmophobia, and doomsday predictions. We certainly should reference false claims such as Hale-Bopp and Elenin so that fewer middle school children fall for that junk science. -- Kheider (talk) 19:25, 6 January 2013 (UTC)[reply]
I note with interest your revert of my edit with the note "No, Oort cloud objects do not bounce "star to star"", which was not what I had written. Since the existence of the Oort Cloud is inferred a lot of its qualities are the subject of speculation. The extent of the Oort Cloud around a star (as I understand it) includes the matter at the very limits of its gravitational dominance, a dominance which automatically passes to the next nearest star and its gravitational field. I don't understand why the effects of the "Galactic tide", which I presume to mean the collective gravitational force of all the matter within the Galaxy, should be larger than that of stars in the neighbourhood. My view of the movement of the outermost parts would be more of a slow drift between the stars. I would love to know more about the reasons behind your emphatic rebuttal. cheers Paul venter (talk) 07:59, 15 January 2013 (UTC)[reply]
You are welcome. I am glad to help. By answering some of your questions/concerns, hopefully the article now better explains how impact possibilities are calculated. -- Kheider (talk) 02:26, 7 February 2013 (UTC)[reply]
Yes - I learned a lot about such impacts and related from your recent edits - Thank you *very much* for your time and effort - it's *very much* appreciated - Enjoy! :) Drbogdan (talk) 03:06, 7 February 2013 (UTC)[reply]
But the reader has no way to know what is hidden behind the figures, so why would he click on the links ? Have you read WP:EASTEREGG, and do you agree with what is stated there ? Regards, Freewol (talk) 16:01, 21 February 2013 (UTC)[reply]
If the reader hovers over the link they will know what it links to and can click on it if they choose to. Since the links are clearly listed in detail below the table I am not sure WP:EASTEREGG need apply. For me it is more an ease of use issue. We are talking about linked numbers in a table, not concealed links in the body of the article. -- Kheider (talk) 18:59, 21 February 2013 (UTC)[reply]
The reader should not have to hover over a link to know what it links to, it's exactly one of the things said in WP:EASTEREGG. I don't see a difference if it is in a table or in the body of the article, it is a general rule about internal linking. It should be clear enough for the reader where any internal link in an article drives to, otherwise he won't click on them. Regards, Freewol (talk) 20:25, 21 February 2013 (UTC)[reply]
I had thought about using parentheses for the links in table , but I felt that would clutter up the table and not every value would have a good bomb yield to compare it to. WP:EASTEREGG is after all just a general guide. -- Kheider (talk) 20:47, 21 February 2013 (UTC)[reply]
Please put yourself in the place of the reader. He can't know where the links are going to, so those links are just disturbing with no added value. They really should be removed from the page to improve it. Of course WP:EASTEREGG is a general guide, but it is very widely followed on Wikipedia and you have not given a reason to go against it. Regards, Freewol (talk) 08:39, 22 February 2013 (UTC)[reply]
It is see also NOT the main body of text and cited to a source. If you think its not realiable then discus that at RSN. -- Lihaas (talk) 13:40, 1 March 2013 (UTC)[reply]
Hello Kheider, I hope you're well. Looks like you're keeping busy! There's a bit of a puzzle that I thought you might be interested in. If you have the time please take a look here. I was hoping for someone else to join the discussion and you sprang to mind (after the work we did on 2005 YU55). Regards, nagualdesign (talk) 05:29, 15 March 2013 (UTC)[reply]
Number of moons in Solar System
Oops. My bad. Perhaps they still count Pluto? And use the outdated number of 4 moons for it? I think we need a new citation for it. — Preceding unsigned comment added by 8.2.215.2 (talk) 20:37, 30 March 2013 (UTC)[reply]
I am using my school computer, so I am under a diff. I.P. address (I usually go by 8.2.215.2, so I am the same person who originally reverted), but I would like to thank you very much for correcting this error. Thank you. — Preceding unsigned comment added by 208.91.96.50 (talk) 17:32, 11 April 2013 (UTC)[reply]
Hello! There is a DR/N request you may have interest in.
This message is being sent to you let you know of a discussion at the Wikipedia:Dispute resolution noticeboard regarding a content dispute discussion you may have participated in. Content disputes can hold up article development and make editing difficult for editors. You do not need to participate however, you are invited to help find a resolution. The thread is "Copernican principle".
Please join us to help form a consensus. Thank you! EarwigBotoperator / talk07:04, 15 April 2013 (UTC)[reply]
I still have half a mind that this user is sincere, although obviously sincere with a fixed opinion that they wish to promote in that article, and possibly pointed to it by others with a more definite agenda. I'm not the most tactful and diplomatic person in these situations, but when I try to imagine what it must be like for someone with zero background in "scholarship" then I start to see where they might be coming from. Apologies to you if I'm teaching grandmother to suck eggs. Lithopsian (talk) 14:38, 10 May 2013 (UTC)[reply]
I have not exceeded it. One of the reverts was by another editor. I have tried to discuss this section blanking with the IP editor User talk:201.215.187.159, but he has used foul language when dealing with other editors and appears to be taking part in multiple edit wars. -- Kheider (talk) 16:00, 28 June 2013 (UTC)[reply]
Google translate
When adding Google Translate URLs to the English Wikipedia, it's probably a good idea to use google.com rather than google.de. The usage of the latter appears to have caused some interesting knock-on effects when the bare URL reference was converted to use the cite web template.
The original article is in Russian, not German. Once the problems were identified, they were easily fixed.
I'm surprised no-one else spotted this in the last five months. Note too, the usage of |title= and |trans-title= in the latter edit. -- 79.67.240.88 (talk) 10:47, 27 July 2013 (UTC)[reply]
Ah! I moved it to the infobox because it was the only image in the article. Apparently the image that was originally in the infobox was deleted, but the bot did not remove the caption. I must not have noticed the difference in the captions. --JorisvS (talk) 07:46, 10 September 2013 (UTC)[reply]
2013 AZ60
Pardon me, but you made an edit to a page I made, 2013 AZ60, and your edit was on Comet Hale-bopp not being discovered until it was 7.2 AU away from the Sun. I don't see how it is relevant to the article, and could you please edit it to make it more understandable or remove it? Thank you. -- exoplanetaryscience (talk) 14:14, 18 October 2013 (UTC)[reply]
I found it odd that when the first few days of observation of an object allowed some small likelihood of it impacting the earth years from now, NASA or others would assert that additional observations would probably rule out impact. One would certainly hope that is the case, but if wishes were horses all beggers would ride. I say this in the perspective of having recently read The Last Policeman, a novel about life in the months before an expected devastating asteroid impact. In that book, the chances of an impact started out small,like for this object, but over time increased. In this case, the chances start out small, but with the prediction that they will doubtless get smaller.Would the same reassuring statements be made by authorities if they were clueless about whether the data would eventually show an increasing or decreasing chance of impact? . Edison (talk) 16:43, 23 October 2013 (UTC)[reply]
If the observation arc is less than 30 days and the nominal orbit is no where near Earth, there is no reason to worry. In 2010, "2005 YU55" had a "1 in 1,640 chance" of an Earth impact on 2103-11-10. We now know that in 2103 November "2005 YU55" will be roughly 2AU from Earth. -- Kheider (talk) 17:51, 23 October 2013 (UTC)[reply]
ISON dissipating
Hello, Kheider.
About your undo of my edit to C/2012 S1, my edit of it was not heavily supported and was gained only from observations of the comet ISON recent movies. However, you claimed it "dissipated" but it did not dissipate completely. -142.136.145.221 (A.K.A Exoplanetaryscience)
ISON more-or-less disintegrated on 28 November 2013 hours before perihelion passage. What we see is probably nothing more than a dust cloud that is dissipating at a rate of around 10 meters per second (22 miles per hour). It takes several days for such a dust cloud to dissipate out of sight. Any surviving fragments are most likely too small to be actively outgassing. What was seen post-perihelion with SOHO and STEREO may have just been the largest clump of material. -- Kheider (talk) 16:58, 2 December 2013 (UTC)[reply]
Hi Kevin - Just wanted to thank you for all your work on the ISON page. We were all certainly hoping the comet would be more spectacular, but then again, I probably wouldn't have ended up seeing Lovejoy if I hadn't followed all the ISON news. It takes passionate people like you to make Wikipedia worthwhile, so thanks for your efforts. Gmporr (talk) 22:00, 2 December 2013 (UTC)[reply]
I list the "last observation date" that the JPL Small-Body Database used to compute the orbital solution. The date could be defined by other criteria. If someone does not specify, the date could also refer to the solution date or the epoch date used. With 1995 TL8 the last observation date used for the solution was "last obs. used 2008-08-29" For the JPL Small-Body Database the date really needs to specify what it means and is referring to. Orbits generally do not make notable changes until there are new observations near a close approach. So it is convenient to list the date of the last observation of the object. -- Kheider (talk) 19:44, 5 December 2013 (UTC)[reply]
Since that makes it read, "(last obs). 2008-08-29." I think the extra punctuation makes it more confusing to know what "last obs" is referring to. If we were going to modify the cite, I would consider going all the way and changing "|date=2008-08-29 |type=last obs" to "|type=last observation: 2008-08-29" dumping the poorly explained date parameter. -- Kheider (talk) 13:24, 6 December 2013 (UTC)[reply]
Convert from date to type since an undefined date is [[User talk:Kheider#last obs|meaningless]]. |type=last observation: 2013-03-12; [[Observation arc|arc]]: 9.11 years
I edited the Tyche page to reflect your mention that Tyche did not exist. Whether you think its OK or not, you can leave a message on my talk page. Thank you and have a Happy New year. --98.183.188.69 (talk) 19:49, 31 December 2013 (UTC)[reply]
Hello Kheider: Thanks for all of your contributions to improve the encyclopedia for Wikipedia's readers, and have a happy and enjoyable New Year! Cheers, Fotaun (talk) 02:00, 3 January 2014 (UTC)[reply]
Send New Year cheer by adding {{subst:Happy New Year 2014}} to user talk pages with a friendly message.
On 9 January 2014, Did you know? was updated with a fact from the article 2014 AA, which you created or substantially expanded. The fact was ... that the asteroid 2014 AA entered Earth's atmosphere on the early morning of January 2, 2014, less than a day after it was discovered? The nomination discussion and review may be seen at Template:Did you know nominations/2014 AA. You are welcome to check how many hits the article got while on the front page (here's how, quick check) and it will be added to DYKSTATS if it got over 5,000. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
On 28 February 2014, Did you know? was updated with a fact from the article 2011 XC2, which you created or substantially expanded. The fact was ... that the asteroid 2011 XC2 missed the Earth by less than 1 lunar distance on 3 December 2011? The nomination discussion and review may be seen at Template:Did you know nominations/2011 XC2. You are welcome to check how many hits the article got while on the front page (here's how, quick check) and it may be added to DYKSTATS if it got over 5,000. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
Good point. Its nominal orbit is indeed worthless, it could be almost anywhere. It seems that all four redlinked objects all have very poorly known orbits, making their true locations undeterminable. I've removed those and listed the three other ones at AstDys. This list also allows to condense the refs and makes the rank no longer border on OR. --JorisvS (talk) 21:56, 27 March 2014 (UTC)[reply]
You have quite the impressive resume for editing the outer Solar System. Normally I would think of you as quite the distinguished contributor. Which leaves me at a total loss as to why you are making an inaccurate edit to the Pluto page. You didn't provide proof of your edit because you couldn't. There is no way in Hades that you can claim that a complete survey of the outer solar system has been made. Instead you were rude and confrontational. Over just six bytes. Six bytes which definitely add to the accuracy of the article. Fine. I'm required to discuss this before it goes to the Administrators' noticeboard, so here is discussion. Show me some actual evidence that I'm wrong, and I will drop it. The ball is in your court. -- Will102
The point of all editors, myself included, is that the Kuiper belt (this is only the classicals and the resonant population within 30–50 AU, so does not include Eris) has been surveyed well enough to say that it is extremely unlikely that an object larger than Pluto is still lurking out there. This does not mean that most Kuiper-belt objects (KBOs) are discovered (most still remain to be discovered), nor does this mean that objects larger than Pluto are lurking further out in the scattered disc or the detached population (in fact, with the discovery of 2012 VP113 the existence of an undiscovered very large (dwarf) planet, possibly more massive than Earth, has been suggested more than once; and this also manages to explain the architecture of the outer reaches of the Solar System rather well: [10]). All of this, however, has no bearing on whether or not Pluto is the largest KBO. --JorisvS (talk) 11:39, 29 March 2014 (UTC)[reply]
In the early 2000s there were multiple surveys by Mike Brown's team. Scott S. Sheppard's team has been doing a survey for a few years now. There are probably many Pluto-sized objects yet to be to discovered in the Scattered disc that are currently more than say ~100AU from the Sun and thus evading discovery. But there is no reason to assume a bright Pluto sized object has been missed by numerous surveys within the traditional Kuiper belt region roughly 30-50AU from the Sun. We can be ~99% certain that any discovered object larger than Pluto will fit Wikipedia's usage of the term Scattered disc object. For a similar reason, we do not worry about discovering an object larger than Ceres inside of the asteroid belt. It is partially a question of semantics since after all the MPC now often lists centaurs and SDOs together. Most people would not consider Sedna to be a Centaur, but the MPC generically lists it as such. Even the DES lists Sedna as SCATNEAR. -- Kheider (talk) 13:46, 29 March 2014 (UTC)[reply]
Updating orbital elements
I was thinking, would there be a way in which we could automate all those recurring updates of orbital elements, maybe a bot reading JPL? --JorisvS (talk) 19:20, 30 March 2014 (UTC)[reply]
Sure a bot could be written by someone, but how many significant figures do we use? I generally use 3 to 5 significant figures depending on how secure the orbit is (U=~9, 6, 4). Do we list uncertainties for secure orbits such as 1000 Piazzia (randomly chosen example)? -- Kheider (talk) 14:12, 31 March 2014 (UTC)[reply]
We could have the bot use the uncertainty in the parameter to determine the number of figures. If we decide that some eight digits or so is too much whatever the uncertainty, then we could add a rule that it is up to a certain number of digits. If we do this, we could include uncertainties only above a threshold value. What do you think is best? --JorisvS (talk) 14:20, 31 March 2014 (UTC)[reply]
I am not sure it is useful to the average reader to list more than 5 sig figs. I think the same rule should be just as good for NEAs as for TNOs. Should the uncertainties be limited to 2-3 sig figs to prevent too much clutter in the infobox? -- Kheider (talk) 15:09, 31 March 2014 (UTC)[reply]
So an uncertainty-limited number of significant figures up to 5 (naturally for all). I don't see how uncertainties of 3 or more figures would be meaningful (even 2 usually don't add anything, really). What if the uncertainty is on the order of several tens (of AU, example)? The most meaningful way to most readers would be to not use scientific notation and include a non-significant figure, I'd say, e.g. in "461 ± 31 AU". --JorisvS (talk) 15:51, 31 March 2014 (UTC)[reply]
Barycentric values are more stable (and accurate) over multiple epochs. Heliocentric values can vary wildly for high eccentricity objects when using different epochs (solution dates). For example, using an heliocentric epoch of 2012-Sep-30 Sedna would have an aphelion of 1011 AU with an orbital period of 12681 years. From 2000 to 2020 Sedna's aphelion varies from about 881 to 1036 AU depending of which heliocentric epoch you use. Given Sedna has an observation arc of 22 years the orbit is secure unlike TNOs with an observation arc of less than a few years. -- Kheider (talk) 14:12, 31 March 2014 (UTC)[reply]
Sure, but don't you have the uncertainties? The aphelion is not 937 AU, not unless it's been determined to within half an AU. Also, it's currently a mixture of barycentric and heliocentric figures, which doesn't make sense. — kwami (talk) 19:28, 31 March 2014 (UTC)[reply]
936.5 AU is the nominal barycentric solution. Horizons web-interface will not show uncertainties. The barycentric solutions is 936.5 AU from epoch 2000 to 2050. The heliocentric solution will change every 6 months when JPL changes epochs making it seem like the orbit is not well determined. We owe it to the readers to use the best solution available when we are dealing with a featured article. -- Kheider (talk) 19:49, 31 March 2014 (UTC)[reply]
DYK for 2012 VP113
On 1 April 2014, Did you know was updated with a fact from the article 2012 VP113, which you recently created or substantially expanded. The fact was ... that Biden is believed to be an eccentric frozen pink dwarf? The nomination discussion and review may be seen at Template:Did you know nominations/2012 VP113. You are welcome to check how many page hits the article got while on the front page (here's how, live views, daily totals), and it may be added to the statistics page if the total is over 5,000. Finally, if you know of an interesting fact from another recently created article, then please feel free to suggest it on the Did you know talk page.
I notice you added some symbols for orbital elements in Sedna and others. Rather than tag them on at every page, could it be added in the template? So the template would show, e.g., "Aphelion (Q) 35 AU". Tbayboy (talk) 18:00, 9 April 2014 (UTC)[reply]
I suppose it could be added to the template, but I am also not sure everyone will want more clutter in the parameter part of the infobox. But (H) has already been added for the absolute magnitude parameter. -- Kheider (talk) 18:20, 9 April 2014 (UTC)[reply]
Thank you for your recent help - my intention of adding the arXivreference to select Comet ISON articles was to help better explain the comet - however, please understand that it's *entirely* ok with me to rv/mv/ce the ref (& related) of course - in any case - Thanks again - and - Enjoy! :) Drbogdan (talk) 12:20, 12 May 2014 (UTC)[reply]
What exactly is barycenter?
I've seen it on many long-period/non-periodic comets' pages, and I get the impression that it is some kind of long-term estimation for the effect on a comet's path, but what exactly is it? I haven't been able to find the barycentric calculation on JPL, and the wikipedia page on it isn't very helpful, so could you try to explain what it is to me? -- exoplanetaryscience (talk) 15:37, 12 May 2014 (UTC)[reply]
For objects on highly eccentric orbits, heliocentric solutions are dependent on the perturbations (position) of Jupiter and thus vary notable over the orbital period of Jupiter. Barycentric solutions account for the combined gravity of the Sun and Jupiter and thus give a more stable (one size fits most epochs) solution. I have a more specific example of how to use Horizons to calculate a barycentric solution for Comet Elenin. -- Kheider (talk) 16:15, 12 May 2014 (UTC)[reply]
Isn't it also practical, with objects with such a large period, for them to also take into account Saturn, Uranus and Neptune- or does that require the 3-body problem? exoplanetaryscience (talk) 00:34, 13 May 2014 (UTC)[reply]
Since Jupiter is more massive than all the other planets combined, the other planets really are not as important and do not vary the solutions as fast. What is important is to compute the solution after the object has left the planetary region so that you have the correct trajectory and velocity. When dealing with comets, I often use 1950 for inbound (before perturbations) and 2050 for outbound values (after perturbations). Another problem is that we technically do not know the mass of the Oort cloud so so we really can not be certain if borderline objects will truly be ejected. So any comet with an orbital period greater than ~100,000 years is really just a best-fit to the data. -- Kheider (talk) 22:02, 13 May 2014 (UTC)[reply]
Speaking of, the theoretical Oort Cloud's distance seems a bit overestimated. Several damocloids such as 2013 BL76 are much further inward than the Oort Cloud ad 50-100,000 AU would be put. Plus, as most of the gravitational interactions between comets are random and accidental, it would be expected that as many comets would have an eccentricity of less than 1 as more than it, meaning that comets with semimajor axes of ~25,000 would be common to find, despite comets with eccentricities of more than 1 being virtually, if not impossible to trace back to their original orbits. I would say it is more likely the Oort cloud resides around 200-10,000 AU from the sun, as that appears to be where most comets come from. But then again, Wikipedia prohibits original research.exoplanetaryscience (talk) 22:09, 13 May 2014 (UTC)[reply]
The Oort cloud should easily extend to 70,000+ AU from the Sun. Defining the inner edge is more a matter of semantics IMHO. The difference between aphelion at 10,000AU and 100,000AU is a very small change in eccentricity (velocity). Obviously, objects that take ~50,000 years to orbit the Sun will come to perihelion much more often than objects that take millions of years. -- Kheider (talk) 22:29, 13 May 2014 (UTC)[reply]
typo
Just wanted to mention that I noticed that in a popular picture of the colors and absolute magnitude of different Kuiper belt objects (right)
Done - FWIW - ran across post by happenstance - uploaded a corrected version - *maybe* a bit better - please revert if otherwise of course - may have to "purge" article buffer to view new uploaded image - in any case - Enjoy! :) Drbogdan (talk) 18:55, 12 May 2014 (UTC)[reply]
I was wondering if you could add the parameter MOID to asteroids' orbital characteristics in the template Infobox planet. I would have added it myself but it appears to have been protected. I'm assuming you're a template editor or know an active user who is, as you seem to have received requests previously about similar things. exoplanetaryscience (talk) 18:16, 16 May 2014 (UTC)[reply]
On your recent edit to 2006 RH120, I looked on JPL's orbit simulator, and during the entire course of 2028 the asteroid never comes any closer than 1.876 AU (mid-march of the year), which could hardly be considered a close-approach. The close-approach data seems very odd considering the asteroid's orbit, but if you go to 2058, the asteroid makes a close approach bringing it only 0.0277 AU (~4.3 million kilometers) from Earth in October of the year. It may verge on original research, but having a certain amount of original research is certainly better than incorrect data, isn't it? 142.136.145.221 (talk) 16:47, 8 June 2014 (UTC)[reply]
Thanks for the thanks, but also, I was wondering...
Do you think it's time to update our MPC-derived images, like this, this or this? Most haven't been updated since 2007-2008; however, given that the number of known objects is likely to skyrocket soon, should we wait until, say, Pan-STARRS comes online? Serendipodous10:30, 9 July 2014 (UTC)[reply]
Oh, and...
The Space Barnstar
Thanks for finding that citation; I sure as hell wouldn't have found it. And while it feels a bit like a capitulation, the guy did have a point, and thanks to you, it has been resolved. Would have been nicer if he'd managed to find it, but oh well... Serendipodous14:37, 12 July 2014 (UTC)[reply]
CS1 Errors
This edit is causing error. {{date=}} parameter is not for writing extended details, when you write details in that parameter it sends itself to the category of errors, look at Category:CS1 errors: dates. Date should only include the Date-Month-Year. Consider reverting all your edits that you've recently made in attempt to recover that error or you want me to do it for you? Thanks. OccultZone (Talk • Contributions • Log) 04:21, 27 July 2014 (UTC)[reply]
"magnitude = 11-36: Can you name a date when the asteroid is brighter than mag 11? This is why Wikipedia:OR is frowned on. On 2009-Dec-16 asteroid was mag 36."
While the asteroid only reached magnitude 11 on the 2014-09-07 approach, the MOID says that it could theoretically be as close as 0.00003 AU from Earth, at which it would likely be at least magnitude 5, if not brighter considering the fact that the provided distance is geocentric and as such it would impact Earth. exoplanetaryscience (talk) 00:47, 30 September 2014 (UTC)[reply]
The asteroid will likely never get that close to Earth due to ongoing perturbations moving the orbit. That MOID value is only valid at the epoch it is defined at. If the asteroid did impact Earth it would become a superbolide brighter than the Sun and the asteroid is not even listed on the Sentry risk table. That apmag 5 claim is way too much "Original Research" for use on Wikipedia since there is not a known date for the asteroid to reach apmag 5. Such a claim is also misleading to the readers. -- Kheider (talk) 03:39, 30 September 2014 (UTC)[reply]
I figured that you might know better than anyone about this. Recently I've been doing a precovery image survey of TNOs such as 2003 UB292, 2008 VM49, 1999 CL119, 2004 XR190, 2012 BX85, and 2005 GX186. I plan ultimately to do a precovery image search of every TNO above H=7 (translating to approximately magnitude 23 or 24). I've managed to precover a few, and has even led to the numbering of 2012 BX85 (420356) because of precovery images from 2003. However I've encountered a problem that the largest portion of them move extremely slowly, so are hard to distinguish from background and permanent objects, and that they're extremely dim and hard to be sure that what I'm looking at is an object in the outer solar system, or a distant starforming galaxy. As a result, I look for images of the same area at wikisky, WISE, and 2MASS, but none of these have quite enough resolution to see dim TNOs of magnitude 22.5 or dimmer, which is most of them. As a result, it's hard to determine where objects of low-certainty are exactly. Do you know of any websites that have large image databases with a resolution near that of SDSS and whose images can be searched by RA and DEC? exoplanetaryscience (talk) 17:06, 18 January 2015 (UTC)[reply]
Do you, by any chance, know why the DES pages talk about "the following table comes from a 10My integration of the orbit of the object.", but then no longer have this table below it (e.g. [11])? --JorisvS (talk) 11:26, 24 February 2015 (UTC)[reply]
I think it is a glitch in the software that prevents the simulation from completing. Since ~2009, I have come to rely on it less and less. Besides, I am not confident it knows a Scatnear from a scatext any more. -- Kheider (talk) 13:33, 24 February 2015 (UTC)[reply]
I know Buie moved it to a different server several years ago and I am guessing some of the software libraries are not completely compatible. But that is just a wild guess. -- Kheider (talk) 14:34, 24 February 2015 (UTC)[reply]
Priorities? I also suspect that is also the reason Brown's dwarf-planet autobot has not been fixed yet. Both are good enough, but have flaws. -- Kheider (talk) 14:55, 24 February 2015 (UTC)[reply]
Good enough? That may be for Brown's list, but with major problems such as not producing any fit or cock-ups like Sedna make the DES practically worthless. --JorisvS (talk) 16:17, 24 February 2015 (UTC)[reply]
I think DES is getting resonances correct. It does not check for high order resonances. I doubt there is funding specifically for the upkeep of the DES software. I suppose Buie treats it like we do Wikipedia articles we plan to get to "one of these days". -- Kheider (talk) 16:27, 24 February 2015 (UTC)[reply]
So: low-order resonances, else not reliable. What about those instances where no result is produced at all, but one or at most a few years ago, it did (e.g. for Eris)? --JorisvS (talk) 16:47, 24 February 2015 (UTC)[reply]
I generally find if you check back a few weeks later, the page that was not generating a 10My integration, will. There appears to be some gremlins in there that are not easy to reproduce. And if the problem is difficult to reproduce, it generally makes it even harder to fix. -- Kheider (talk) 16:54, 24 February 2015 (UTC)[reply]
Bennu asteroid
Hello, I noticed in the Bennu asteroid article that is an Apollo asteroid, and now I read that it is more likely that it originated from the Main Asteroid Belt: [13]. I don't know much about this; is this info contradictory or complementary? Thnks, BatteryIncluded (talk) 23:28, 20 April 2015 (UTC)[reply]
Classifications like 'Apollo asteroid' are solely based on an object's current orbital elements. Where it originated does not matter, and because all planet-crossing orbits are highly unstable, all NEOs must have come from somewhere else. It looks good, something that can definitely go into the article. --JorisvS (talk) 08:20, 21 April 2015 (UTC)[reply]
Welcome Back
Ah, I was wondering where you were while I was going through the asteroids. I tried to be transparent and tried not to be too "bold" (I'll leave that to Boleyn). Glad you're back. ~Tom.Reding (talk ⋅contribs ⋅dgaf)16:41, 15 May 2015 (UTC)[reply]
Padenton
Padenton, you have reverted me twice without explaining exactly what WP:NASTRO policy guideline *you* think I changed. I have better explained the current policy, but I did not change accepted practices. -- Kheider (talk) 00:02, 18 May 2015 (UTC)[reply]
You have "better explained the current policy" to support your point of view and interpretation without any consensus whatsoever. ―Padenton|✉00:06, 18 May 2015 (UTC)[reply]
In case you were thinking otherwise, I would like to note that I support your edits to WP:NASTRO, however that this has become bigger than it really should have been. However, I have been hesitant to take a position on the matter for fear of being dragged into it too. While I agree with your edits to WP:NASTRO, I believe, not only Padenton, but you, and essentially everyone involved has collectively let it grow into something much worse. exoplanetaryscience (talk) 22:22, 18 May 2015 (UTC)[reply]
I do not blame you. I was basically gang raped by Padenton who should have done a partial revert. I will be slowing down on Wikipedia as I have more important things in the real world to deal with. -- Kheider (talk) 14:40, 19 May 2015 (UTC)[reply]
I'm glad you do, because I've blocked you for 48 hours. I was kind of shocked when your edit summary for the above turned up on my watchlist; you simply can't use language like that on Wikipedia, and absolutely not about a named user. If you think there are good reasons why you should be unblocked, you may appeal this block by adding below this notice the text {{unblock|reason=Your reason here ~~~~}}, but you should read the guide to appealing blocks first. Bishonen | talk14:57, 19 May 2015 (UTC).[reply]
This is ridiculous! Padenton's has been crying foul about Kheider and tried to put Kheider in a bad light, definitely assuming bad faith about his motivations here. This being so focused on him personally, I understand why Kheider would take this as a personal attack. Even though he expressed how he felt about the situation in a less than ideal way, a block is over the top, and for 48 hours no less. And Padenton gets not even a warning for his part in this. --JorisvS (talk) 15:24, 19 May 2015 (UTC)[reply]
I haven't studied this situation — admins are volunteers, and my time is limited. I blocked Kheider for an absolutely unacceptable comment (unacceptable regardless of provocation) that I noticed. "Less than ideal", you think? I came this close to revision deleting it, edit summary and all. I have read the thread you link to, but I don't see anything very remarkable there. If you think Padenton needs to be sanctioned or warned (and you could be right, as I say, I haven't studied it), I suggest you take the matter to WP:ANI. Bishonen | talk17:19, 19 May 2015 (UTC).[reply]
There was a discussion at WT:WikiProject Astronomy (especially the section Semi-automated bot request to redirect asteroid stubs > 2000 due to a large number of AfD (the section above it). There, editors agreed on certain things. Kheider's edits were either simply fixing typos, clarifying what was written, or adding what had been agreed over at the WikiProject Talk. Then, more than a week later, Padenton comes by and starts to edit war over this. He did start a discussion at the talk page (WT:Notability (astronomical_objects)#Changes without consensus), immediately assuming bad faith about Kheider "I repeatedly find disgusting your attempt to assert ownership of this article.". Kheider responded very well and linked to the discussion on which his edits were based and explained the individual changes. Instead of simply continuing the discussion there, Padenton then went to ANI and placed at edit-war notice on Kheider's talk page, even though he was the one with more reverts in it. Then Kheider really just expressed how he felt about this all and was summarily blocked for 48 hours for it. And it is still not clear with what Padenton actually disagrees, despite all this and my attempts to get him to say it. Given the context in which it was said (and having worked pleasantly with Kheider for a long time), I find a block ridiculous. And if you do not have the time to properly assess the context and therefore know which action, if any, is appropriate, I sincerely doubt you should have been the one taking action. --JorisvS (talk) 09:03, 20 May 2015 (UTC)[reply]
Bishonen, a block seems a bit excessive here. He is not literally saying he was gang raped, he was venting on his own talk page. The most uncivil behavior on Wikipedia is actions, rarely words. Words like these are a reaction to actions, though not to be excused or condoned, at least a warning first would have been appropriate. imho.--Milowent • hasspoken18:38, 20 May 2015 (UTC)[reply]
Thanks for the comments, everybody, but I'm not changing my mind. "Not literally saying he was gang raped"? Gee, no, I never did think he meant it literally. All we have here, any of us, is actually text — words, language — so Milowent, I don't quite see what you mean by calling Padenton's words "actions" and Kheider's words "words". Text and words are the only medium available to anybody here. (Except a few special button available to admins, but Padenton isn't one.) Words have the power to hurt and harm. Sexualized and violent metaphors contribute to a "guy" or macho environment on Wikipedia that more and more women are complaining about. I'm sure it's unacceptable to many men also. And that was hardly your common or garden sexualized violent metaphor, either. Also, I told Kheider up front how to ask for review by an uninvolved admin. He hasn't; but if such an admin should come by spontaneously, I'm happy to leave the decision to them. Bishonen | talk20:31, 20 May 2015 (UTC).[reply]
I've done the crime and the time. Lucky me. Actually, I can accept trading a 48 hour block for still being allowed to express my feeling towards some of Wikipedia's greatest flaws when it comes to the wiki-police and how it is common for a gang of users to ridicule others without fully studying the facts simply because they do not have the time and/or are enforcing some policy written by the wiki-police. There is a reason newbies are reluctant to become regulars on Wikipedia and most editors that have edited Wikipedia for as long as I have, just basically retire and walk away. What is funny is that during the asteroid re-direct discussions of March and April I was not even around to discuss the consensus that developed. I did not make a single edit to Wikipedia from March 5 to May 1. It will be a great loss to Wikipedia content (vs the wiki-police force and policies) if editors like myself leave because members such as Padenton are allowed to group attack people without bothering to properly look into the facts. Perhaps I should move my near-Earth asteroid work over to a SETI website, but then I would probably have to leave Wikipedia to prevent being further accused of a COI with my edits. After all, Wikipedia itself is NOT a reliable source, it is the verifiability of the reliable sources. -- Kheider (talk) 16:17, 21 May 2015 (UTC)[reply]
It would, of course, be your choice, but it would be a great loss to Wikipedia and I and certainly many others would hate to see you leave! I hope people like Padenton and Bishonen won't discourage you from making your many positive contributions. --JorisvS (talk) 18:55, 21 May 2015 (UTC)[reply]
I am not leaving too soon. But it is politics like this that makes one wonder after 9 years. Plus one also needs to consider other life events. I sincerely appreciate the support I received during my "2-day vacation". Thank you all. It helped. Now I need to figure out what middle ground might exist with the whole Deletionism and inclusionism in Wikipedia asteroid debate.-- Kheider (talk) 19:15, 21 May 2015 (UTC)[reply]
I'm glad you decided not to leave. Good luck with the deletionism vs inclusionism thing, though...I've found that the deletionists are the most intransigent folks around. You either agree with their efforts, or too bad. — Huntster (t@c)19:25, 21 May 2015 (UTC)[reply]
I've been in Prague for the last few days so I missed this whole kerfuffle. Wow. This sort of thing is what breaks Wikipedians, on top of the complete lack of thanks for the job we do. Sorry to see you go through that, Kev. Things need to change and fast if Wikipedia is going to last another decade. As far as deletionists go, there are always ways around their claws, if you're clever. Serendipodous11:11, 22 May 2015 (UTC)[reply]
It is the Herd behavior. One person screams bad faith on every page they can. Another person sees some merit to the claim, but does not properly research the cause of the problem so also writes up a report, and before long, the original problem is overlooked and the "outsider" is crushed (I might have used a different term). -- Kheider (talk) 11:32, 22 May 2015 (UTC)[reply]
Mean anomaly
I notice that you have been reverting my WolframAlpha-sourced changes to the J2000.0 mean anomaly value. If this is because WolframAlpha is inaccurate, then thank you, JPLSSD is definitely a better source! However, please note that per discussion here and here, the mean anomaly value is only meaningful and accurate if it is the mean anomaly at J2000.0 (1/15/2000 12:00 GMT). Are the JPLSSD values for the mean anomaly at this precise time? (Also, do you think you could shoot me a link for the precise place in JPLSSD where you are getting the values?) A2soup (talk) 12:27, 23 June 2015 (UTC)[reply]
Yes, I and Urhixidur have used Horizons at epoch 2000-01-01 12:00. As an example, for Mercury, go to the JPL Horizons link for Mercury. Select "Ephemeris Type" and change to "Orbital Elements". Change Time Span to "2000-01-01 12:00" and "2000-01-02". When you generate ephemeris, Horizons will show "MA= 1.747958829506607E+02" for "2000-Jan-01 12:00". Horizons is reference #4 for Mercury and is used to describe "Orbital characteristics" in the infobox. -- Kheider (talk) 13:01, 23 June 2015 (UTC)[reply]
Okay, well I tried it out and that looks good to me. I never would have guessed WolframAlpha would be wrong on something like this. Thanks so much for the help and sorry for the hassle. A2soup (talk) 15:24, 23 June 2015 (UTC)[reply]
[14] Although it'll once have said 11400 years, I currently can't find neither 11400 years nor 4.154E+06 in the cited source ([15]). I do find "PER= 10950.89409". --JorisvS (talk) 12:14, 19 July 2015 (UTC)[reply]
Thank you. Yes, I know heliocentric solution are worthless for these. The citation should link directly to that so that it can be verified without having to go through such a process, which apparently is already the case, so now I don't know why I didn't find the number of days before using the search function of the browser). Additionally, there should be note that indicates where to look for it (I've added one).
Looking at the various "PR="s listed, they all state 4.153811E+06, with only the next digit varying between 3 and 7. Is this how accurately we know the barycentric orbital period of Sedna? --JorisvS (talk) 13:53, 19 July 2015 (UTC)[reply]
The PR= 4.154E+06 is accurate over hundreds of years, but like all orbital elements will vary daily if you use enough sig figs. This is also why I seldom use more than 3 to 6 sig figs even in an infobox. -- Kheider (talk) 17:02, 20 July 2015 (UTC)[reply]
So how much can it be expected to vary for objects on orbits like Sedna's? What would be the primary causes of it? The mass distribution of the Solar System not being static. Galactic tides? --JorisvS (talk) 10:14, 21 July 2015 (UTC)[reply]
Cybele, Pallas, and Hygiea
Vesta's not a DP because of the impact at its south pole, not because of size. It underwent particular circumstances, circumstances that did not happen to Pallas, Hygiea, and Cybele. Just because X asteroid of comparable size got hit does not mean all are. We know about the same about Cybele, Hygiea, and Pallas in 2015 as we did in 2007. The info is still good in this case. --DN-boards1 (talk) 03:50, 12 September 2015 (UTC)[reply]
Such claims are borderline rubbish given how much less massive Cybele, Hygiea, and Pallas are. But the quality of Wikipedia has been dropping the last year or more. -- Kheider (talk) 03:58, 12 September 2015 (UTC)[reply]
They are still valid claims, and Pallas is barely less massive than Vesta. Pallas, Vesta, Hygiea, Cybele, Ceres, the original object that Psyche is the remains of, and the original object that the Eunomia family is the remains of all formed as dwarf planets. Vesta was hit in the south pole, throwing it out of equilibrium. Psyche was stripped of everything but its core, which MIGHT (and this is a big MIGHT) still be in equilibrium. Eunomia got smacked to bits, the largest part (Eunomia) possibly, but unlikely, another dwarf planet.
Eunomia and Psyche aren't likely to have stayed in HE after their catastrophes, and Vesta for sure did not. But Cybele, Pallas, and Hygiea quite likely DID form in HE, and never experienced catastrophic impacts like those that Vesta, Psyche, and Eunomia did. Therefore, they SHOULD still be in HE. Images from Hubble of Pallas show a round object. --DN-boards1 (talk) 04:04, 12 September 2015 (UTC)[reply]
10 Hygiea is not very spherical at 530x370 and 65 Cybele does not look good at 300x230. These claims are very misleading as it is even doubtful that Pallas would even qualify as a dp. I have no doubt the belt HAD many dwarf planets before Jupiter's disruptive gravitational scattering destroyed most of them billions of years ago. -- Kheider (talk) 04:21, 12 September 2015 (UTC)[reply]
However, we can't rule out the possibility that Cybele and Pallas are in HE yet. Hygiea is fairly certain to not be, but Pallas and Cybele still stand a solid chance of being in HE. 300 x 230 approaches 300 x 300, which is HE, yes? Correct me if I'm wrong. --DN-boards1 (talk) 04:27, 12 September 2015 (UTC)[reply]
We can be confident that they are no longer in HE due to the disruptive behavior of the asteroid belt. Collisions in the asteroid belt are often at higher speeds than the Kuiper belt and objects in the asteroid belt are generally rockier. -- Kheider (talk) 04:37, 12 September 2015 (UTC)[reply]
And another thing. What about Interamnia? It's close to the proper dimensions for HE, and we don't know much about its shape. It's big enough, though...Is it possible Interramnia is a DP? --DN-boards1 (talk) 04:33, 12 September 2015 (UTC)[reply]
Now, we can remove Ceres, known to be a dwarf planet. Vesta, Hygiea, and Davida aren't dwarfs. But of the rest, where do they stand? Which do we know enough about that we know they can't be dwarfs? You said that Interamnia's dimensions are poorly known, so we can place that in the "maybe" pile. Pallas is bigger than Vesta, and looks rounded, even, so we can put it in the "likely pile", and with Cybele being the right shape and size, it can go in that pile too. Hygiea fails the shape and density test, so goes in the "not" pile. But where do the others fall? --DN-boards1 (talk) 04:46, 12 September 2015 (UTC)[reply]
In a nutshell Wikipedia needs to explain the difference between a failed protoplanet and a dwarf planet. Objects in the asteroid belt smaller than ~500km will not be dwarf planets as we are not talking about icy Kuiper belt objects. Note that even Pallas is NOT likely to be a dp. -- Kheider (talk) 04:53, 12 September 2015 (UTC)[reply]
Having a nicely round shape does NOT mean that it is in HE: a bowling ball has an HE shape, but is not in HE. See Methone (moon). Vesta is the most massive belt object after Ceres, and it was not big enough to pull itself back into shape after a collision (which it would be able to do if it was in HE -- that's what the term means). Pallas was the only belt object that had a chance, but the Hubble image shows it not to be (and Hubble was after Weintraub). Tbayboy (talk) 14:37, 12 September 2015 (UTC)[reply]
Iapetus is nicely round, but it is not in hydrostatic equilibrium, either, and it is icy and much bigger than Vesta. Methone may well be in hydrostatic equilibrium, though. It is likely made of ice fluff, which doesn't have much strength, which is why a body that small could be in HE. Nevertheless, it would be rather unreasonable to call it a dwarf planet and not call Iapetus a dwarf planet if they were in solar orbit. --JorisvS (talk) 14:45, 12 September 2015 (UTC)[reply]
With an eccentricity greater than 1, C/1980 E1 is on an ejection trajectory and no longer orbits the Sun. You can not use a negative semi-major axis without misleading readers. -- Kheider (talk) 13:18, 26 September 2015 (UTC)[reply]
I'm not going to accept that assertion without any evidence. The semi-major axis is one of the defining parameters of a hyperbolic orbit and you're suggesting that people would be misled by including this important information. Please state what exactly you believe the presence of this useful information will lead them to believe. The SBDB doesn't list the apoapsis because this object is on an escape trajectory, so at no point will it reach it farthest away point; I don't see what this has to do with including information on the semi-major axis though... Perhaps you are confused with the difference between the apoapsis and the semi-major axis of an orbit? 84.12.140.139 (talk) 17:09, 26 September 2015 (UTC)[reply]
Firstly, I don't think that the "average reader" will be reading an article about an obscure comet, in the same way that articles about complex numbers aren't read by average readers. Secondly, just because the correct information might be confusing is absolutely no reason to censor it. I found it far more confusing to see that the semi-major axis field was "Not Applicable" (I see that this has now been revised). 84.12.140.139 (talk) 19:02, 26 September 2015 (UTC)[reply]
(talk page stalker) Anon, listing either perihelion, semi-major axis, or aphelion (which in this case does not exist) alongside eccentricity (and four other parameters not relevant to this discussion) is sufficient to uniquely determine an orbit. Perihelion is listed, hence its orbit is uniquely determined by those values. Semi-major axis does not serve that purpose and listing a negative value, though technically correct, does not normally mean much to a reader, and hence is not useful. --JorisvS (talk) 17:54, 26 September 2015 (UTC)[reply]
In this effort to eliminate redundancy do you also propose to remove this parameter from the table on this page. I think that nearly every maths article has derived values and equations which could also be culled too! If you're so concerned that readers aren't going to be able to understand this then perhaps the negative value could link to the article on hyperbolic orbits, or have a note attached explaining this mathematical quirk. It seems arbitrary to decline including this information just because it's negative, thank goodness that the inclination is greater than zero or this might not be included too! I dispute that this value is not useful, I came to this page specifically for this information (expecting a negative value I should add). 84.12.140.139 (talk) 19:02, 26 September 2015 (UTC)[reply]
That's apples and oranges. A positive semi-major axis is very meaningful to most if not all readers. And inclination is positive—it's a value between 0 and 180°. A negative inclination is the same as a positive one with the ascending node 180° different. What did you want to do with its semi-major axis value? --JorisvS (talk) 19:10, 26 September 2015 (UTC)[reply]
Obviously the comparison to derived equations in mathematics articles was for effect, but I believe that it's inconsistent to remove the semi-major axis field here and not for every other orbit for which the periapsis or apoapsis is given. I was being flippant about the inclination. I imagine that the set of readers for whom the term "semi-major axis" is meaningful but whose brains explode on seeing a negative value there is very small indeed. Any reader who thinks that the semi-major axis for a conic section must be positive is misinformed. The page for semi-major axis doesn't say anywhere that the value must be positive, in fact in the third paragraph it specifies that the value may lie either side of zero. Every other equationfor hyperbolic orbits on Wikipedia is in terms of the (negative) semi-major axis, and not in terms of the periapsis, in fact the only equation I can find elsewhere which is written in terms of the periapsis is one to find the semi-major axis! 84.12.140.139 (talk) 19:45, 26 September 2015 (UTC)[reply]
A negative semi-major axis for hyperbolic trajectories is mathematically sound. For elliptical orbits the interpretation of the semi-major axis is straightforward: the average distance. However, this interpretation makes no sense for a negative semi-major axis. That's the big difference. --JorisvS (talk) 23:11, 26 September 2015 (UTC)[reply]
I'll ask the question more directly: what is it that you think will happen if a reader encounters a negative value for a semi-major axis when she is not expecting it; the most likely outcome I can think of is that she ends up learning something new, a worthy outcome indeed. It's worth noting that the average distance is only valid when one takes the average over the eccentric anomaly. If you consider this the sole reason for inclusion of the semi-major axis on all the elliptic orbits listed on Wikipedia I'd ask you why the semi-minor axis isn't listed as it too has every right to be the "average distance" of the orbiting body; I'd posit that the semi-major axis is included elsewhere because it's far more useful in its own right! The interpretation for the semi-major axis for elliptic orbits and hyperbolic orbits is exactly the same as the interpretation of the semi-major axis for ellipses and hyperbolas, i.e. half the distance between the intercepts of the line passing through both foci. If the little minus sign causes you so much grief, feel free to use a positive value and fly in the face of convention elsewhere... 84.12.140.139 (talk) 23:52, 26 September 2015 (UTC)[reply]
C/1980 E1 is being ejected from the Solar System. To suggest to the reader that it has an average distance of 58AU from the Sun is horribly misleading. Numerical integration shows that after 2013-Dec-24, it will *never* again be 58.268AU from the Sun. Why do you want to mislead the readers? -- Kheider (talk) 00:45, 27 September 2015 (UTC)[reply]
I think you misunderstand what the semi-major axis is used for, it has a significance far beyond the average distance of an elliptic orbit. My intention in putting this information into the article was clearly not to mislead; I decided to put it in because I myself had come looking for this information and hoped I could improve the experience of others coming after me. 84.12.140.139 (talk) 01:19, 27 September 2015 (UTC)[reply]
Your average reader will not know what a negative semi-major axis is. Without explaining "in detail" what a negative semi-major axis means, I can not see how listing an unexplained negative semi-major axis is going to help the layperson. Wikipedia readers have a hard enough time understanding that different epochs generate different orbits. -- Kheider (talk) 01:33, 27 September 2015 (UTC)[reply]
That argument could be made about innumerable topics on this website, and is no reason by itself to not include information. My suggestion earlier was to attach a note to the value either linking to Hyperbolic trajectory or Semi-major axis or even just to say "The semi-major axis of hyperbolic orbits is negative by convention" 84.12.140.139 (talk) 01:40, 27 September 2015 (UTC)[reply]
I just happen to come by to reply to another discussion taking place on your talk page. However, observing the great length of your talk page, I wanted to suggest that you look into archiving your talk page to keep it cleaner, shorter, and easier to work in. --JustBerry (talk) 01:32, 27 September 2015 (UTC)[reply]
+1; although, while I do now appreciate that I might be the wrong person to be quibbling with you about trans-Neptuniancelestial mechanics, your talk page length is a bit much. You can move your Barnstars, DYK's, etc. to your user page or another subpage linked to from here or your user page, FWIW.
Or not, or you can do nothing, it's up to you! But, if you want, I can even provide a sample "haircut" of your userspace, and you can always revert if you aren't happy with it :) -- Kendrick7talk05:24, 18 October 2015 (UTC) Meanwhile some kids on the T last week suggested that I'm rocking a mullet, so, really, who am I to judge?[reply]
Theory vs. hypothesis
At Formation and evolution of the Solar System, we have "The current standard theory for Solar System formation, the nebular hypothesis" [emphasis mine]. At Nebular hypothesis, we have "is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System". Yet we call it nebular hypothesis? Do you know any good reason not to move it to "nebular theory"? --JorisvS (talk) 12:47, 13 October 2015 (UTC)[reply]
Nibiru
I just got an email from David Morrison; not something I expected would ever happen again. Apparently, the web weather around Nibiru is getting a bit stormy; stormy enough at least for him to get swept up in it again. There does seem to be an upswing in Nibiru interest at grok.se and Google Trends but it appears to focus on this Youtube video which is so transparently a sundog I don't really know what to do with it. This is the closest I can find to a reliable source on the topic; the Irish Independent did a frankly shameful write-up on it which makes me question whether they can ever be called a reliable source. Any ideas as to where to go from here? Serendipodous09:14, 29 October 2015 (UTC)[reply]
Yes, I know it's in the past (of course), and patently it was not true, but why is it not valid to discuss, in the article about PHAs, public fears about PHAs. It's certainly notable that NASA felt it necessary to issue a denial. SpinningSpark20:18, 6 November 2015 (UTC)[reply]
This is User:Georgewilliamherbert in disguise... Out of curiosity are you on the Minor Planet Mailing List? Just saw flurry of alert stuff on there about WY032FF / 2015 YB... aha, my mail archive dragged you out from MPML posts in 2014 and 2013. Good job on the prompt update of the page here! 208.66.205.104 (talk) 01:13, 18 December 2015 (UTC)[reply]
Online tool
Dear Kheider, here's a link to the online tool I created for the revision of minor planet articles on wikipedia. Please check it out and give me a feedback if you want to. It is still a beta-version with lots of bugs and debug-comments, but it should work. Kind regards, Rfassbind– talk16:01, 23 December 2015 (UTC)[reply]
On citespam and the Monthly Notices of the Royal Astronomical Society
There are now tools that actually rank a paper's impact by how many times it gets cited in Wikipedia [16]. This is a terrible idea, of course, for science, for Wikipedia, and it's unfair for the researchers themselves. An actual link in the citation does not seem to be necessary. Therefore, when a particular research group appears too often in too many articles, it's probably spam. This is a completely separate issue from the question of reliability. For the time being, most editors still think that being cited in Wikipedia "doesn't matter", but when it becomes widely known that it does matter enough to create COI issues, then I think the pitchforks will come out and guidelines on spam will be re-written to address this specifically. Geogene (talk) 02:28, 24 December 2015 (UTC)[reply]
I didn't say it was fringe, and I didn't say I want to ban the paper from Wikipedia, but I think that research is getting a lot more attention from Wikipedia, overall, than it merits. It's hard to tell how to weight it since most of that stuff doesn't have secondary sources. Questioning this isn't censorship. This link you gave [17] seems to be a press release, and yet, it's linked from List of meteor air bursts. Speaking of that article, the fact that I've generally left it alone has more to do with my not wanting to antagonize you than it has with my opinion of the sourcing there. I'll continue to avoid it. Geogene (talk) 17:14, 28 December 2015 (UTC)[reply]
Most meteor airbursts do not have peer-reviewed papers written about them. Small airbursts generally only have newspaper articles that at best quote a local professor. You have not left the article alone. On 16 April 2015 you deleted a lot of material from the article because you felt newspaper articles were not reliable enough. I was ok with most of that, but deleting a peer-reviewed paper is somewhat extreme. But you and I have had this talk before. It is simply unknown how often rotational bursting causes small asteroids to create short-lived "asteroid streams" that will disperse over many decades. -- Kheider (talk) 19:19, 28 December 2015 (UTC)[reply]
This is quite interesting, and seems to be good for WP. Yes, COI disputes will arise, but what ends up staying are the facts. Editors all watch each other's pages, and if a reference is useful, COI or not, it should, and probably will, stay. I can only see this as more motivation to remove {{citation needed}} tags, and make people cite their edits more frequently, which is where help is needed. ~Tom.Reding (talk ⋅dgaf) 18:39, 9 January 2016 (UTC)[reply]
Venus
I have nominated Venus for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here. Anon09:51, 8 January 2016 (UTC)[reply]
Sortkey 0-padding conventions for numbered asteroids vs preliminary
Do you know, or can you guess for me, why, for most categories that contain them, the preliminarily-designated asteroids are predominantly sorted without 0-padding, while the much larger number of numbered asteroids use 0-padding? Preliminary designated asteroids span (correct me if I'm wrong) the 19th-21st centuries, so it would be much easier to find them in a 0-padded list (they would be clumped) than in an article-name sorted list (they would be scattered), if that list contained both numbered and unnumbered asteroids. My guess is that this is a historical artifact of Wikipedia, perhaps because this interaction wasn't taken into account, or because it was easier at the time (prior to tools like AWB and the like), or that it was done prior to the mass-creation of numbered asteroid stubs. ~Tom.Reding (talk ⋅dgaf) 18:31, 9 January 2016 (UTC)[reply]
Neat, so they range from 1077 T-2 to 6879 P-L, indeed, scattering them very far apart in any list that contains these sorted by name and 0-padded numbered asteroids. ~Tom.Reding (talk ⋅dgaf) 19:06, 9 January 2016 (UTC)[reply]
Planet Nine is basically known as Planet Nine. There is no need to go into "nicknames" in the lead. -- Kheider (talk)
Orbits
Check my recent edits to see the other articles I updated, and then let me know if I have made systematic errors. In that case I will fix them. JehochmanTalk15:32, 23 January 2016 (UTC)[reply]
Quick answer: Eccentric orbits are complex and barycentric solutions are more stable and reliable for highly eccentric objects. Heliocentric solutions vary a lot and change too often because of Jupiters 12 year orbit. When heliocentric solutions are used for highly eccentric objects, it is very important to state the epoch used for the solution. -- Kheider (talk) 15:35, 23 January 2016 (UTC)[reply]
I might, but I am still somewhat undecided. I do not see how having the number is harmful. Sedna is still not as well known as Eris and Pluto. -- Kheider (talk) 19:33, 24 January 2016 (UTC)[reply]
full fragmentation/current status of P/2010 V1
As has been made clear in the recent Comets mailing list discussion on comet P/2010 V1 (Ikeya-Murakami), the comet has been fragmenting significantly in recent times with fragments ABCDE recognized by the MPC and fragments FG(H?) remaining not accepted. I have a project with the dynamic orbits of comets to work on at the moment, and I would greatly appreciate if you could do what you can to update the article to what is currently known. exoplanetaryscience (talk) 16:56, 7 February 2016 (UTC)[reply]
Should the current artist's impression be removed from the Planet Nine infobox?
Hi Kheider, I just want to run something by you regarding this. JPL and MPC only provide a mean motion term with units of deg/day. {{Infobox planet}}'s closest parameter is |p_mean_motion=, which has units of deg/year (there is no |mean_motion=). I assumed I could multiply JPL's deg/day value by 365.25 to determine |p_mean_motion= since:
the Mean motion article doesn't distinguish b/w "proper" & "regular" mean motion ("proper" doesn't exist on the article page),
{{Infobox planet}} doesn't provide any description of the |p_mean_motion= parameter (and excludes |mean_motion= param),
JPL/MPC (as far as I can tell) only provide |mean_motion= and not |p_mean_motion=.
My questions/observations are:
{{Infobox planet}} should say whether or not |p_mean_motion= = |mean_motion= * 365.25 is correct
I see. Thanks! I'll update the infobox doc & make an edit request for the template, so more editors are informed. I might even add AstDys to my code at some point to populate the proper elements. ~Tom.Reding (talk ⋅dgaf)14:22, 25 March 2016 (UTC)[reply]
Broken SureWest.net URLs
Hey Kheider, I was cleaning up a reference error on 349 Dembowska when I noticed a dead link with your name on it. I ran a search which found 42 total like this. Spot-checking a few of these, I found that they're mostly, if not all, dead. Can you restore the documents to their current URLs or provide a new link to the old content and update these refs? Let me know if you want my automation services for any help. Thanks. ~Tom.Reding (talk ⋅dgaf)00:53, 7 May 2016 (UTC)[reply]
Hello, Kheider. Voting in the 2016 Arbitration Committee elections is open from Monday, 00:00, 21 November through Sunday, 23:59, 4 December to all unblocked users who have registered an account before Wednesday, 00:00, 28 October 2016 and have made at least 150 mainspace edits before Sunday, 00:00, 1 November 2016.
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Hi Kheider, I've done some additional changes in 2012 DR30.
I saw you re-added the centaur classification to the article which seems to agree with the dynamical classification by DES but not by any means how JPL/MPC define centaurs. Don't you think that we should stick to a consistent classification system for all MPs on Wikipedia? I was also guessing that ejected centaur might apply, but you removed that as well. Is this just a special case I shouldn't worry about? Rfassbind– talk22:52, 14 February 2017 (UTC)[reply]
Extended centaur is the correct term and the category should probably be renamed. Ejected generally refers to something being completely removed from the Solar System. Many astronomers use the term centaur in place of minor planet since most minor planets are full time residents of the inner Solar System. But you could just call it a minor planet. -- Kheider (talk) 03:54, 15 February 2017 (UTC)[reply]
Reply:
The terms ejected centaurs/extended centaurs are not defined on Wikipedia. "Extended centaur" is used in some MP-object articles (ad hoc definitions).
However, Nakamura lists more than 40 damocloids, and it may well be that using the Tisserand param (Jewitt) of 2 or smaller will render many more minor planets if we compile the entire catalog.
For 65489 Ceto ("Centaur–extended"), the term seems synonymous with "Neptune-crossing TNO".
For 2013 AZ60 ("extended centaur"), both TNO and Centauer are linked as MP-cateogry in the infobox. This is fundamentally against Wikipedia's broad division of minor planets into asteroids, cis- and trans-Neptunian objects, as listed in {{Distant minor planets sidebar}}
2012 DR30, you replaced the acronym OCO with ICO, which probably should emphazise the "inner" in "Oort cloud objects", yet this is not an abbreviation I find elsewhere. If for these objects barycentric orbital parameters are so important, it would be much better to have a dedicated infobox-section, as otherwise systematic (automated processes) will hardly be feasible.
I understand that these articles may have evolved organically over the years with smaller changes (Damocloids asteroids→Damocloids) adding to the variety of terms and definitions. To me it is confusing and adding another undefined/unsource term like "Extended centaur" to some MP-object articles is just not good enough. What you think? Best, Rfassbind– talk09:51, 15 February 2017 (UTC)[reply]
Many objects in the Solar System go by many names/categories. Avoiding the term Centaur just because it is not the 1980-1990 definition does not benefit the reader. The MPC uses the term "distant" simply because they recently decided they did not want to bother with all the categories/semantics. There are 2311 TNOs of which only 304 have perihelion (q) less than 30.1 AU. As a result, many astronomers refer to non-resonant planet crossing TNOs as centaurs to separate them from the unexcited Kuiper belt objects that stay beyond Neptune. Heck the line between TNO and comet is a fine one based mostly on the current perihelion point. -- Kheider (talk) 15:25, 15 February 2017 (UTC)[reply]
The abbreviations/terms ICO (inner Oort cloud) and OCO (outer Oort cloud with a>1500AU) are fairly new and came about at the same time as ETNOs. Even Sedna is a ICO. OCOs can have their orbits modified by the galactic tide. TS2016 (pg 5) says ICOs should have q>70AU so I think it might be best if infoboxes do NOT use the abbreviations ICO or OCO as the terms/abbreviations are poorly defined. -- Kheider (talk) 13:03, 16 February 2017 (UTC)[reply]
Barycentric solutions are important for highly eccentric orbits, because without them you windup with objects like C/2017 A3 (Elenin) that show an aphelion (Q) of 27,495,663 AU (434.77537 ly) with an orbital period of 50,975,277,342 years. -- Kheider (talk) 15:25, 16 February 2017 (UTC)[reply]
Thank you for your feedback. The issue of classifying minor planets by orbital groups is certainly not trivial. I think we do approach the subject very differently, and while I try to find the best possible criteria to consistently classify minor planets on wikipedia without striking contradictions, you don't seem to share my endeavor. Maybe this can not be achieved, or maybe there is a lack of trying. I'll come back to this post in the months to come... hopefully with a more concise concept, so you can give me your feedback again. Thx & till then, Rfassbind– talk00:28, 21 February 2017 (UTC)[reply]
"Little wiki boxes"... I like that. But seriously, I think you know already that the MPC-list you just mentioned is very unfortunate. The MPC does neither define nor use any orbital classification of non-asteroids consistently: that's why 2012 DR30 is classified as a generic "distant object" on its object page. Also, if you follow the link of my previous post, you find a simple grouping by semi-major axis for the 3 major minor-planet categories, which are: asteroids (cis-Jovians), centaurs (trans-Jovians to cis-Neptunians) and TNOs (trans-Neptunians) with a division at 5.5 and 30.1 AU for their semi-major axis, respectively. Within these three "little boxes" there can be as many sub-classifications as needed, using additional orbital criteria such as q, Q, e and i. And of course, the answer of my very first question in my first post above is a resounding "yes! We should classify MP-objects consistently on wikipedia". To be followed, best Rfassbind– talk23:06, 22 February 2017 (UTC)[reply]
I am not sure every minor category needs to be based strictly on semi-major axis. That might be too simple. If literature refers to something as a centaur, I see no major issue. I see no problem with a handful of objects sitting in the "extended centaur" category while outer Solar System terminology matures. In 2013 the MPC specifically listed 12DR30 as a Centaur. The MPC actually cuts TNOs off at a>50AU, thus their combined Centaur (inward) / SDO (outward) list. -- Kheider (talk) 05:27, 23 February 2017 (UTC)[reply]
Ejected centaurs
Hey there, and welcome back to wikipedia I suppose! I've actually missed you a bit for help with some small body articles (we went through all of 2016 without a single linked asteroid on the asteroid approach list) as well as a fantastic wikipedian in general. Either way, I figured as the creator of category:ejected centaurs, that it was more of a filler category for objects that aren't necessarily damocloids/extinct comets, and orbit beyond Neptune, yet still remain under significant perturbational (rather than resonant) gravitational influence from any or all of the major planets. If you want to move it to category:Extended centaurs as suggested in the above discussion, I believe it would be quite appropriate. exoplanetaryscience (talk) 00:07, 22 February 2017 (UTC)[reply]
Thank you for the kind note Exoplanetaryscience. I think I will move the category. I have been trying to better describe the category so that it might be of more use and better understood by other Wikipedians. You have been doing great work the last year. -- Kheider (talk) 14:03, 22 February 2017 (UTC)[reply]
uo3l91 > 2013 SY99 cleanup
Would you mind quickly cleaning up the now officially designated 2013 SY99? It's probably only a matter of hours before news sites notice it, hours I don't have at the moment. exoplanetaryscience (talk)
Greetings Kheider! I noticed your many recent updates to comet infoboxes, thanks for that. FYI, you can save yourself some typing by using {{cvt}} instead of {{convert}}, which automatically sets the |abbr=on parameter. See an example of how it works. — JFGtalk07:11, 11 April 2017 (UTC)[reply]
Thank you for the coding shorthand. After editing Wikipedia for years, sometimes I get too set in old ways with cut & paste. -- Kheider (talk) 13:30, 11 April 2017 (UTC)[reply]
dealing with virtual impactors
How should we deal with the virtual impactors list after they (hopefully) don't hit us? Should we leave it up there, or take stuff off as it misses, or something else? exoplanetaryscience (talk) 19:52, 17 April 2017 (UTC)[reply]
Seems good to me, just making sure I can coordinate properly. Might want to make it clear that the objects are NOT going to be hitting us when that time passes- you know, for idiot protection! exoplanetaryscience (talk) 02:23, 18 April 2017 (UTC)[reply]
Uploading and inserting thumbnails
Hi Kevin,
I recently created File:2023-10-14annularsolareclipsephases.jpg (a completely original piece of work based on my own software) to insert into the article on the October 14, 2023 annular eclipse. I can't figure out how to access the smaller-sized version to insert in the article. But perhaps a bigger question is whether you think it would be an appropriate addition; I was planning to add it to the right of the animated gif. Please let me know what you think... thanks!
Andrew
Uploading and inserting thumbnails
Hi Kevin,
I recently created File:2023-10-14annularsolareclipsephases.jpg (a completely original piece of work based on my own software) to insert into the article on the October 14, 2023 annular eclipse. I can't figure out how to access the smaller-sized version to insert in the article. But perhaps a bigger question is whether you think it would be an appropriate addition; I was planning to add it to the right of the animated gif. Please let me know what you think... thanks!
Hello, Kheider. Voting in the 2017 Arbitration Committee elections is now open until 23.59 on Sunday, 10 December. All users who registered an account before Saturday, 28 October 2017, made at least 150 mainspace edits before Wednesday, 1 November 2017 and are not currently blocked are eligible to vote. Users with alternate accounts may only vote once.
The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.
Kheider, this edit is not the best way to go. By directing readers to the archived version by default, you present them with the data we are using in the article, rather than whatever it might be at a future date. When we update the article, we can re-archive the SDBD page. — Huntster (t@c)04:36, 13 December 2017 (UTC)[reply]
Exactly. That's what we don't want for a dynamic website like that. We want readers to see exactly the material we cited, rather than whatever it may be in the future when a new dataset is generated. — Huntster (t@c)17:12, 13 December 2017 (UTC)[reply]
No, we really don't. All the data cited to that page on the SBDB should be from a specific epoch. Your footnote solution is useful only if you are referring to a past event not reflected in the data set we're using for the article (which it does well in the Phaethon article). A unique reference would be redundant because, again, we are referring to a specific epoch as the rule, rather than as the exception. — Huntster (t@c)18:31, 13 December 2017 (UTC)[reply]
For outstanding contributions to astronomy, space exploration, and solar system objects. Have a great 2018 and thanks for your contributions. Fotaun (talk) 17:22, 28 December 2017 (UTC)[reply]
Simplified JPL-cite for minor-planet articles
I propose to simplify minor-planet articles, by adding ;cad=1 to the URL of the <"jpldata" /> citation. Example:
<ref name="jpldata">{{cite web
|type = 2016-09-12 last obs.
|title = JPL Small-Body Database Browser: 7482 (1994 PC1)
|url = http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007482;cad=1
|publisher = [[Jet Propulsion Laboratory]]
|accessdate = 3 February 2018}}</ref>
I think I noticed this useful URL extension in one of your edits (but I cant be sure). As far as I see, we no-longer need a redundant <"jpl-close" /> cite when ;cad=1 is added to "jpldata" since this little addition opens up the "Close-Approach Data"-section. Do you agree with that? Best, Rfassbind– talk04:39, 3 February 2018 (UTC)[reply]
1. As far as <"jpl-close" /> is concerned, when dealing with more notable asteroids, it might be better to have a second reference with a direct link to say https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=99942;cad=1#cad to skip over the Orbital Elements and Physical Parameter tables. Many readers will simply not know about JPL's Close-Approach Data for objects.
2. Is there a reason we do NOT directly link to a real asteroids name? ie, why 2007482 instead of the shorter and MPC correct asteroid number 7482?
Agreed. A separate "jpl-close"-citation for more notable objects such as 99942 Apophis is helpful and should be kept. (I propose to define "more notable", as: any article rated above "start-class" and/or above "low-importance").
The SPK-id is a unique identifier for all objects on JPL's SBDB. Currently any MP-number seems to perfectly match with its corresponding object page, so using SPK is purely optional for numbered minor planets. (This may change when the 1-million mark is crossed. Due to LSST-discoveries, his day may arrive sooner than we think!). Actual "names" should never be used (as we both agree). For unnumbered minor planets, the principal prov. designation may change while the ID doesn't (which is only a minor, "cosmetic" issue). SPK-id is also appropriate for comets. For example, comet C/1949 K1 can be easily referenced by the unique identifier. SPK also works with template {{JPL}} as just demonstrated.
Good catch. A "close-approach"-item is missing indeed. It seems to be uncontroversial, as ;cad=1#cad does not throw an error, even if there is no such section in the object page.
So I assume #1 and #2 is fine with you (otherwise you would have let me know). Here's a related question I came across today: Do you know what is "Amphi" in the body-column of the CAD section of 10476 Los Molinos? Thx, Rfassbind– talk22:02, 20 February 2018 (UTC)[reply]
Over in the Talk:Messier 58, you said of Deep Sky Videos that "Random people on youtube are generally unreliable sources/non-notable.". This is not a criticism of your removal of what were in fact throwaway remarks, but of your notion that the scientists on Deep Sky Videos are random people, and are "generally unreliable sources/non-notable" Deep Sky Videos is one of a number of video channels run by video journalist Brady Haran who was awarded an honorary doctorate for his work on YouTube with the University of Nottingham. Primary contributers to Deep Sky Videos are Professor Mike Merrifield, the head of astronomy at the University of Nottingham and an expert on galaxy evolution; Paul Crowther is a professor of astrophysics at the University of Sheffield, whose interests include massive stars; Dr Meghan Gray, STFC advanced fellow and lecturer at the University of Nottingham, her research combines galaxy evolution and a long-standing interest in gravitational lensing; and more recently, Dr Rebecca Smethurst, Sixty Symbols Ogden Fellow at the University of Nottingham, who does research into the co-evolution of galaxies and black holes. These are videos presented by professional astronomers, and made by a professional video journalist who, before he started working with the University of Nottingham, worked at the BBC. Their work across all the channels is highly respected, some of it award winning within the science community, and funded in part by the scientific community. Everlong Day (talk) 17:23, 7 February 2018 (UTC)[reply]
I watched the youtube video in question. At no point did I expect them to think their nickname would be taken seriously. Unless their name for M58 catches on, the name itself has zero notability. -- Kheider (talk) 18:04, 7 February 2018 (UTC)[reply]
I noticed you reverted my edit on linking to A106fgF. I wanted to mention that I intended on creating an article on it (and still do) primarily because while impact is not necessarily certain (or even probable) we haven't had any other objects with a 'reasonable' chance of impact in a while. I talked to one of the ATLAS PIs and he said that the odds of it having impacted earth are about 9%. I'm currently reviewing the discovery images, and may possibly be doing a thorough review paper on the subject. At any rate, I just wanted to let you know that I consider an article on the object would be notable, whether or not it did end up impacting. exoplanetaryscience (talk) 04:48, 24 February 2018 (UTC)[reply]
You can write the article but there really are not any reliable sources to reference or suggest public interest. Even Bill Gray wrote that A106fgF was probably a near miss event and there is zero evidence of atmospheric entry. -- Kheider (talk) 14:45, 24 February 2018 (UTC)[reply]
Tom seems to like the idea. So go head and write A106fgF. I will see what I can add. But I am not sure there will be a lot of content. PS: The observation arc for 2010 GZ60 has been extended by 3 hours removing it from the list of virtual impactors.-- Kheider (talk) 18:33, 24 February 2018 (UTC)[reply]
Well like I said, there's quite a bit of research to be done before it becomes article-ready. It might even not, but that'll take some work to find out. Just to note, at the lower end of its size range, it could have released as little as 0.005 kt-equivalent energy, which is more than an order of magnitude below the detection limit of the detectors that CNEOS sources from. exoplanetaryscience (talk) 23:18, 24 February 2018 (UTC)[reply]
Kheider: source for Category:Cold Classical Kuiper belt objects is Mike Brown's How many dwarf planets are there in the outer solar system?, where the term "cold classical" currently applies to 341 TNOs. There are no TNOs labelled "hot classical". Currently, the category has been added to 18 TNOs on wikipedia, 16 of them are articles (including 2 unnumbered ones). As far as I see, to most of these articles a "(cold)" was added to the infobox in |mp_category=. However, this classification tag is neither linked nor does it appear in the body of the article.
Do you see a need for a basic discussion on how to deal with these TNO subclasses? First thing I see is:
to make sure that the article classical Kuiper belt object sufficiently defines these sub-classes by orbital parameters (if possible), and that these definitions are presented for feedback and consensus at WT:AST .
When this is done, minor-planet object articles (body and infobox) and categories (top) can properly link to the definitions and explanations provided in classical Kuiper belt object.
Based on our orbital classification conversation on ejected/extended centaurs and damocloids from February 2017, this may not be an easy thing to do. However, if we proceed on different/uncoordinated paths, we will potentially change each others edits several times. This post tries to avoid this situation. Hope we can cooperate, Rfassbind– talk12:57, 9 March 2018 (UTC)[reply]
PS: I think the category's name should be "Cold classical Kuiper belt objects", not "Cold Classical Kuiper belt objects". I also notice that it was created just a day after the redirect were created/implemented. Coincidence?
Yes, the terms cold and hot as well as inner classical Kuiper belt object are used in the peer reviewed literature. (All three subdivisions are mentioned here together). I've written my lengthy post above because of the problematic approach you have chosen: to create a category first (adding it to a small number of articles; plus an unlinked infobox-tag), seemingly without prior discussion and consideration for the overall project, while I have resisted to create "my" inner-classical category before things are sorted out.
This seems to me avoidable monkey stuff, where editors shoot first and ask questions later. More precisely:
What's the limit for the "cold" population? Shall the inclination be smaller than 5° (as I recently added), or ≤4° (as in the adjunct citation), or <10° (as in Kuiper belt § Classical belt)?
What criteria does Mike Brown's website use (see above)? Is it different?
Shouldn't the creation of a "cold" category be accompanied with a "hot" category? After all, this is an either/or division, isn't it?
More recently, the cold classical Kuiper belt objects have been divided further into a "kernel" and "stirred" sub-population. (Also see SETI-talk, OSSOS on YouTube at 24min.) This must be evaluated, otherwise "everything" needs to be redone.
Follow-up: based on the Johnston's archive, this plot shows the TNO subclasses in the core region (a: 38–49 AU; i: <40°). This could be helpful for the discussion, I think. Rfassbind– talk12:59, 12 March 2018 (UTC)[reply]
Thank you for the plot and other links. I need to look into the semantics more, but a quick look seems to suggest "inner classic" objects would not be the same as "cold classical"? Mike Brown is defining a cold classical by the simple criteria of 41<a<47 and i<5. -- Kheider (talk) 14:23, 12 March 2018 (UTC)[reply]
Yes, inner/outer and hot/cold classical Kuiper belt objects are different classes. Apologies if my posts somehow implied that they were the same. No hurry as long as no one starts to populate your cold-object category (with 18 pages). As for Brown and his website (listed on top) there is no mention of the criteria "i<5", so that needs further clarification. Rfassbind– talk14:50, 13 March 2018 (UTC)[reply]
I prefer only moving objects to a category if there is a reliable source(s) specifically listing it in that category, as that seems to be the method for asteroids inside of Neptune. It just seems like a cleaner method and Wikipedia is suppose to go by the sources (in a perfect world). I am somewhat leary of Wikipedia cherry picking specific orbital parameters as that also depends on the sources used. Brown's method is overly simplistic, but robust methods require a 10 million year integration of the orbit and such lists can be hard to come by. It can be a slippery slope. Do you know what criteria Johnston uses for inner/outer classical? -- Kheider (talk) 15:44, 13 March 2018 (UTC)[reply]
Johnston's Archive classifies the inner/outer classicals according to Gladman et al. (2008) (implicitly stated), the same source as used in the corresponding section on Wikipedia. Unfortunately, I feel like my questions never get a direct answer from you, but I'll take your last slipery-slope-reply as a "No" to my question as to whether or not you acknowledge that with the creation of Category:Cold Classical Kuiper belt objects, you have taken the initiative, and the questions above now need to be resolved in order to avoid inconsistencies or even confusion. That's fine with me. No hard feelings. What interests me more is your support when I need it to get things done. Best, Rfassbind– talk22:37, 21 March 2018 (UTC)[reply]
PS: coincidentally, I just came across Megan Schwamb's thesis where she divides the cold/hot classicals at the 5-degree mark as well (p.3; bottom of the 20th PDF page), so with another source, I'm confident to go along the process I previously laid out.
Hi Kheider, you'll probably want to know this, although I don't think you could get away with posting it just yet: A/2018 F4 is weird. I performed a search for precovery images with DECaLS and was able to rule out any orbital solutions with e = 0.965 to 1.004 and 1.050 to 1.077. Either it's a typical halley-like or long period comet (e < 0.965), an unusually eccentric hyperbolic comet (1.004 < e < 1.050), or a bona fide interstellar object (e > 1.077). I'm not sure what this thing is exactly, but it's definitely not normal. exoplanetaryscience (talk) 14:49, 5 April 2018 (UTC)[reply]
I noticed that you added my paper on 2004 EW95 to the external links in its wikipedia article. Thanks very much! I was curious as to whether you have any intention to add the paper's findings to the body of the article? I'd be happy to make an edit to the article but I wanted to check first in case you were already working on something.
Hello @Tseccull: (Tom), thank you for the message which reminded me to add the link to the body of the article. I have done a basic clean-up of the article, but as one of the authors it would be great if you could add more. -- Kheider (talk) 14:27, 16 April 2018 (UTC)[reply]
Do you approve of an expansion/renaming of template {{JPL SBDB Jupiter Trojans}} with additional columns for mean-diameter estimates from Akari and IRAS (SIMPS)?
Also, most edits made to 18 large Jupiter trojans by an anon user during 3–13 March 2018 are hardly helpful (those with overly long edit comments). Since going through all these edited articles take a lot of time, and I don't want to get into a potential WP:EDITWAR with said anon user all by myself (wasting additional time better spent on other tasks), I need to know whether you approve of/ are in favor of such revision. Thx, Rfassbind– talk16:39, 27 May 2018 (UTC)[reply]
Thanks for uploading File:MinorPlanet-2007uk126-19970930.gif. The image description page currently specifies that the image is non-free and may only be used on Wikipedia under a claim of fair use. However, the image is currently not used in any articles on Wikipedia. If the image was previously in an article, please go to the article and see why it was removed. You may add it back if you think that that will be useful. However, please note that images for which a replacement could be created are not acceptable for use on Wikipedia (see our policy for non-free media).
Hello, Kheider. Voting in the 2018 Arbitration Committee elections is now open until 23.59 on Sunday, 3 December. All users who registered an account before Sunday, 28 October 2018, made at least 150 mainspace edits before Thursday, 1 November 2018 and are not currently blocked are eligible to vote. Users with alternate accounts may only vote once.
The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.
I read in an old blog that there's a HST image of 10 Hygiea that reveals its shape (though presubably at low res). The link was dead and I haven't been able to find it. If you can, I think it would be a worthwhile addition to the article, maybe replacing the 2MASS image I just added. — kwami (talk) 22:14, 13 April 2019 (UTC)[reply]
I saw an image of it on twitter during one of the conference IIRC from SPHERE on the VLT, it was round like it was in hydrostatic equilibrium. I haven't seen an official version yet though. Agmartin (talk) 02:32, 2 October 2019 (UTC)[reply]
FA Review for Ceres
I have nominated Ceres (dwarf planet) for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here. 20:18, 21 June 2019 (UTC)
I would suggest the shorter "Objects removed from the Sentry Risk Table". But keep in mind only two comets have ever been listed. -- Kheider (talk) 16:57, 7 July 2019 (UTC)[reply]
"Objects" is an unfortunate term which will be changed to "Astronomical objects" by the WP:CFD-folks (don't you think?). Also, the quantitative distribution of NEAs and NECs is irrelevant for naming the category. I'll go with the proposed Category:Near-Earth objects removed from the Sentry Risk Table and regroup the category's items into numbered, unnumbered and named objects. If you want to have things differently, you're welcome to make further amendments. Rfassbind– talk22:24, 7 July 2019 (UTC)[reply]
Hi Kheider. We normally use ±1σ, don't we? I ask because in the Pluto info box we copied ±2σ from the source. I halved it, but wanted to check. — kwami (talk) 04:08, 14 September 2019 (UTC)[reply]
I had an idea about calculating sigma a for the barycentric orbits using the vectors available from JPL to see which of the hyperbolic comets had semimajor axes > 0 when that was included. But when I compared the downloaded and calculated semimajor axes, some didn't match. It turned out that one day while collecting data I forgot to select @0 to get barycentric data so about 100 or so of them are heliocentric semimajor axes. So those numbers in that big comet file I posted are wrong. Next time I'm at the public library I will get the right data ( OCD ) and replace that backup file. Agmartin (talk) 02:21, 2 October 2019 (UTC)[reply]
I have made that type of mistake many times myself. Sometimes when switching from a NEA to a comet, I find myself looking at results for @399 instead of @sun and laughing when I get an eccentricity of 1E+08. -- Kheider (talk) 03:44, 2 October 2019 (UTC)[reply]
The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.
Finding your page is illuminating in the current environment, gotta trust the info by you regd 29 april, so is it surely missing now, guess thats why the lockdowns are receeding too, any risk of cyanogen from comet atlas tail? Thanks. Kbxads (talk) 17:24, 21 April 2020 (UTC)[reply]
The fragments of ATLAS will not get any closer than ~117 million km from Earth. A comet's tail is very thin and that is why the solar wind pushes it away from the nucleus so efficiently. There is no risk. -- Kheider (talk) 17:57, 21 April 2020 (UTC)[reply]
The article will be discussed at Wikipedia:Articles for deletion/2000 YH2 until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.
Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article. Sam-2727 (talk) 02:36, 1 May 2020 (UTC)[reply]
Hi! I just noted your addition to Limiting magnitude It seems reasonable, but do you have a source? I guess astronomy is big for you. (I just finished a pier with a deck for my 12" SCT. Unfortunately I am in the Atlanta area and will never have dark skies. If it does not work out, I can remove the scope and mount and replace it with a bird bath or table top.) — Neonorange (Phil) 22:54, 19 August 2020 (UTC)[reply]
I have added some sources. :) After adding Note C to 2020 QG, it is good to have some sources in the limiting magnitude article. You are obviously big into astronomy if you have a pier mounted 12". Enjoy using (imaging) with your scope. -- Kheider (talk) 01:24, 20 August 2020 (UTC)[reply]
2020 QG
The table you just added with the pre- and post-pertubation data is awesome. ONly problem, you did not provide a source for those data. Could you please add one? Thanks. N2e (talk) 04:11, 24 August 2020 (UTC)[reply]
Oh, my bad on that. I see now that there are two sources added; blame it on my bad eyes, or poor perception of the small print. ::However, while I can parse the data and confirm the first source (https://ssd.jpl.nasa.gov/) for the first row of that table, I'm having trouble verifiying the source at https://ssd.jpl.nasa.gov/horizons.cgi and figuring out how to find the numbers you've placed on the second row. Could you perhaps help me see how you got those numbers? Cheers. N2e (talk) 06:32, 24 August 2020 (UTC)[reply]
"Center" should already be set for "Sun (body center)" (aka @sun)
For "Time Span" I selected "2020-May-31" to match the current JPL SBDB numbers and "2020-Dec-01" with a step size of 6 months. -- Kheider (talk) 06:43, 24 August 2020 (UTC)[reply]
Thanks, that is very helpful. I can see how it is possible, from that source, to get those numbers that are shown in the table. Since that data is dynamic, and generated by subsequent data base queries from that URL page given at the source, I have no idea how an internet archive copy for the Wayback Machine would, later, show the correct data; as that Horizons DB and calculator had it figured on today's date, 23 Aug 2020. But I def agree that the source does support the data you've helpfully added to the second row of the table. N2e (talk) 07:02, 24 August 2020 (UTC)[reply]
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I totally take your point about "currently observable", as it excludes comets we technically "know" but are way off the scopes. However I think mentioning that we're talking about natural objects is also useful. One could argue that Voyager 1 is currently observable, as we routinely receive its radio transmissions (and in fact communicate bidirectionally with it). --johantheghost (talk) 10:20, 11 February 2021 (UTC)[reply]
The numerous known comets that are currently more than 150 AU from the Sun are natural objects. Voyager 1 is the only spacecraft. The causal reader is going to assume visually observable. In the lead, I am not sure we can be more specific without getting way too wordy. -- 14:40, 11 February 2021 (UTC)
JPL now has 11163±6 yr, but I can't tell if that's heliocentric or barycentric. Are we able to better constrain the period than the ≈ 11,400 yr we currently have in the article?
The JPL SBDB always lists the heliocentric value. Next to the bold yellow JPL 34 you will see (heliocentric ecliptic J2000). It is currently 11,163 years. In 6 months it will be 11,500 years. In Jan 2019 it was (PR= 3.8352E+06 days) "10,500 years" and in Jan 2025 will be (PR= 4.75E+06) "13,000 years". This is why the barycentric solution is much more reliable at different/random epochs. I have switched the Sedna reference to a Batch call. -- Kheider (talk) 14:35, 18 September 2021 (UTC)[reply]
Thanks. Do we have an estimate of the uncertainty? (The spread at horizons_batch.cgi is just 2 years.) If it's within a century, I wouldn't want to include the '≈', but it would be good to have an idea anyway.
If stellar disturbances mean the period varies significantly, I think it would be fine to give our best measure for the current orbit, and mention how much it's likely to vary between orbits. — kwami (talk) 21:52, 18 September 2021 (UTC)[reply]
I do not know if Horizons accounts for stellar perturbations. Luckily stellar perturbations should not matter much for objects inside of 1500au. Looking at JPL 34, we can assume the 3-sigma uncertainty in the orbital period is around ±20 years. But I am not sure we should jump to that assumption in the article. This topic might make a good paper for someone that does stellar perturbation simulations. -- Kheider (talk) 23:39, 18 September 2021 (UTC)[reply]
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Hi, this topic may be too detailed for the Wikipedia:WikiProject Astronomy page so I am responding on your talk page instead. I suspect that the main benefit for OD accuracy of newly discovered comets long period comets would be from the parallax effect due to Earth's orbit around the sun. I would expect better improvement from a 3 month precovery than from a 2.0 year precovery that provides a smaller base for "triangulation". Annette Maon (talk) 07:59, 4 January 2022 (UTC)[reply]
Observing geometry for a 3 month precovery would be less important than a significant 2 year precovery. The comet would have physically moved much more over 2 years. -- Kheider (talk) 10:46, 4 January 2022 (UTC)[reply]
The comet would indeed travel a longer distance over 2 years. However, if it is on a highly elliptical orbit at a distance more than 5AU from the sun most of that movement would be in the radial direction. A 2.0 year precovery image would be taken from roughly the same place in Earth's orbit and would therefore show little movement on the celestial sphere. On the other hand a 3 month parallax would show several degrees of movement with respect to the celestial sphere even for a comet 10AU away that would not move much in those 3 month. Annette Maon (talk) 11:50, 4 January 2022 (UTC)[reply]
Astrometry would not care if it was 1-day, 3-months, or 2-years. A longer observation arc is almost always better because it shows long-term movement. And most precovery images occur near opposition when the comet will be closer, brighter, and up most of the night. Earth moves around the Sun at 30km/s. At 7au a comet like C/2017 K2 will be moving ~16 km/s. In 2 years the comet will move about 1 billion km. In 3 months it will move about 1/8 that. Without a reliable source there will never be more than a vague one or maybe two line footnote in Don't Look Up (2021 film). About all one could say is, "In the movie Comet Dibiasky is discovered with a short 5 hour observation arc with no mention of precovery images. In the real-world you would need precovery images extending the observation arc to many months to have a high confidence of an impact when announcing an Oort cloud comet impact 6 months away." But even that might be too much Original Research without a reliable source. -- Kheider (talk) 16:12, 4 January 2022 (UTC)[reply]
Imagine you need to determine the orbit of a comet with an ecliptic orbit moving almost straight toward the sun. Assume it is discovered at a distance of 5 AU. Would you rather have the last observation as well as 4 precovery images for a total 5yr arc but all at opposition, or one 3 month old precovery image? Annette Maon (talk) 18:32, 4 January 2022 (UTC)[reply]
Let's make life simple. Given 5 observations on the vernal equinox of each of 5 consecutive years all showing your comet exactly at the vernal equinox (at opposition), how would you even determine that the distance is 5AU? Would you be able to get any information about the radial velocity? How accurate would that determination be? MOID is obviously zero, but how can you tell if the Earth will be at the intersection if you can't know when the comet will reach that point? Are you sure you wouldn't rather have some parallax? Annette Maon (talk) 22:27, 4 January 2022 (UTC)[reply]
Most comets have inclined orbits that come to opposition at closer to 140-170 degrees. And as a general rule you will have 3 observations of each field on any given date in a survey archive. MOID only needs to be near-zero as the two-body orbit constantly changes as the comet passes through the inner Solar System. Though the observing geometry you describe is not ideal, there is zero reason to assume that the observations will be captured exactly 365 days apart as comets vary in brightness night-to-night. For an undetected impactor a larger parallax is important for automated software to pick it up. And if your 5 year arc (all imaged near opposition) shows zero movement in the comet, you probably already have the answer you need. -- Kheider (talk) 23:34, 4 January 2022 (UTC)[reply]
All your true statements only make it less believable that a real astronomer would pronounce a 100% probability that a newly discovered comet will hit Earth. I am still trying to find a conceivable scenario in which such a statement could be made with a straight face. This is why I chose an ecliptic orbit with perihelion below 1 AU - those are guaranteed to have a near-zero MOID whereas any significant velocity perpendicular to the ecliptic would create an extremely low probability for a near-zero MOID. A near-zero MOID may not guarantee a collision but a large MOID guarantees a 0% probability. If you want to make the example more realistic imagine that all the observations from your 5 year arc fit a straight line with a small and constant (angular) velocity on the celestial sphere and a gaussian distribution of measurement errors around that.
If the 5 year arc shows zero movement of the comet, there would be no way to determine its distance or its radial velocity. It would therefore be impossible to know when the comet will reach the MOID and whether the Earth will be there at that time. Why would you think I have all the answer I need to pronounce a 100% probability that such a comet would hit Earth? Annette Maon (talk) 07:16, 5 January 2022 (UTC)[reply]
If you have just discovered said comet, you have already detected some movement in the three most recent photos even if your precovery images show none (precovery images maybe an older lower resolution camera even if on the same telescope). In the event of an Oort cloud comet impacting Earth in 6 months with high confidence, the observation arc (including precovery images) would need to be months/years, not hours/days. In the movie I see no mention of precovery images, only 5 photos (1h ago, 2h, 3h, 4h, 5h ago) with a 4 HOUR arc (What the Minor Planet Center would call a "single-nighter"). You can not expect serious science in a Hollywood movie as no one would want to watch the snorefest. This is why the less accurate Armageddon (1998 film) is a cult classic and Deep Impact (film) is more scientific. -- Kheider (talk) 14:14, 5 January 2022 (UTC)[reply]
90377 Sedna - featured article review
I have nominated 90377 Sedna for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here. Renerpho (talk) 05:45, 3 May 2022 (UTC)[reply]
319 Leona occultation
Hello Kevin! Thanks for your recent addition to 319 Leona. The occultation of this asteroid by Betelgeuse was the topic of the very first edit I ever made on Wikipedia (over on the German version) and on Wikimedia Commons, both in October 2012. So this brought back some nice memories! I was surprised to see that the English article didn't include any mention of the event. After creating the article SOLEX (software) today, I added the image [19] to the Leona article, to illustrate the occultation path. Maybe you can assist with including additional information? I marked the new 319_Leona#2023_occultation_of_Betelgeuse section as "needing expansion". Some info can be found here, but I am also looking for other sources, since this one is from 2004. Renerpho (talk) 05:55, 8 May 2022 (UTC)[reply]
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Linking to my talk page (as you have done) doesn't tag me, like {{u|Renerpho}} and {{re|Renerpho}} would have done. Your talk page is on my watchlist, otherwise I wouldn't have seen your question...
It's no secret that I wasn't happy with the state of that article when I nominated it for FARC last year. I was hoping that I'd find time to work on it; unfortunately that didn't happen, and in the end the result of the FARC was keep. I'm okay with that, even though it's probably not turning into my favourite article any time soon.
For something that's going to appear on the main page, the text of Wikipedia:Today's featured article/November 14, 2023 dumps a lot of numbers on the reader in the first few sentences. Compare this to the November 2010 nomination, which managed to convey the key information with almost no numbers (except the orbital period). Is there a reason why we shouldn't do something very similar again?
We have already discussed the second sentence (For the majority of its orbit it is the most distant known object in the Solar System other than long-period comets.) on the article talk page earlier today; that's no longer true. The rest of the 2010 text still seems to reflect the current state of the article.
By the way, could you please archive some of your talk page? I find it almost impossible to reply to your comment because the page is extremely large. Surely most of the 280 sections are no longer active. Renerpho (talk) 20:26, 31 October 2023 (UTC)[reply]
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![[19]](https://commons.wikimedia.org/wiki/File:Leona_Betelgeuse.png){kind=link}