Talk:(308635) 2005 YU55

C/2010 X1
Close approach between C/2010 X1 and 2005 YU55 will be on Sep. 13, minimal distance about 0.1688 AU.

Trajectory animation
Is there any chance that the animation can be slowed down (considerably!) so that it might be used as a means of gauging where the asteroid will appear on the night sky? In fact, even then it would be very crude, so could somebody please upload a sky map or provide a link to one? I will search for one myself, too. Thanks. nagualdesign (talk) 02:13, 7 November 2011 (UTC)


 * This is for GRAS telescopes in New Mexico, but it might help. (Ian Musgrave November 4, 2011) -- Kheider (talk) 02:28, 7 November 2011 (UTC)


 * Thanks for the speedy response. The page you linked to also uses the word 'embiggen', which I found quite amusing! I'll see if I can use the information to produce a copyright-free skymap myself, so that I might upload it for others to enjoy... nagualdesign (talk) 03:14, 7 November 2011 (UTC)


 * Okay, I've uploaded a PNG to File:2005-YU55-Trajectory-8th-Nov-2011.png. Please could you help me to fit this somewhere in the article, properly scaled and wotnot. nagualdesign (talk) 04:52, 7 November 2011 (UTC)


 * ...Or let me know if it's the wrong filetype or not suitable, etc. Thanks. nagualdesign (talk) 04:53, 7 November 2011 (UTC)


 * I have now added a thumbnail to the article page, so no help is required. Please let me know if I've made any mistakes though. I haven't done this before and only discovered the picture tutorial tonight. nagualdesign (talk) 06:01, 7 November 2011 (UTC)

Perhaps it's an oddity of my MSIE 9 under Vista, but the caption of the animation
 * is
 * showing
 * as
 * one
 * word
 * per
 * line

which very much upsets the layout. If I knew more about formatting or if the topic were not attracting much attention I might try adjusting the "width" parameter to something other than 1. Jim.henderson (talk) 12:58, 7 November 2011 (UTC)


 * Can't really help you there, Jim. Sorry. One thing I have noticed though is that the diagram assumes a moving coordinate system where the Earth is stationary and the Moon follows a circular (or eliptical) orbit, but the path followed by the asteroid does not drift to the right as it should. It's as if the Earth has stopped in its orbit. I don't suppose it matters, it's just a bit odd to those who understand celestial mechanics. nagualdesign (talk) 22:46, 7 November 2011 (UTC)


 * I've uploaded an alternate version of the trajectory diagram and boldly uploaded it to the article page. Compare the old version to the new version. Is that any better? Takes care of the caption problem at least. Regards, nagualdesign (talk) 07:03, 11 November 2011 (UTC)


 * I have mixed feelings on the new animation. The original animation does give a better idea of where the asteroid is coming from. -- Kheider (talk) 13:32, 11 November 2011 (UTC)
 * Maybe a combination of both? Add, for example, a dashed trajectory for the motion in the corotating frame? --JorisvS (talk) 14:17, 11 November 2011 (UTC)
 * I thought that the original animation gave the impression that the asteroid was coming almost straight from the Sun, when in fact it's in orbit around the Sun. Having said that I will alter the animation later tonight to show the apparent motion. Thanks for the feedback. nagualdesign (talk) 23:05, 11 November 2011 (UTC)
 * Given the asteroid has an orbital eccentricity of 0.42, the Earth has a near-zero eccentricity, and how zoomed in the animation is, I believe that that the asteroid would have the appearance of coming from the Sun direction. We are zoomed in almost tight enough to only encompass the orbit of the moon. -- Kheider (talk) 23:29, 11 November 2011 (UTC)
 * Yes, I can understand the mechanics. And the asteroid certainly appeared to approach from the direction of the Sun. However, the lines in the diagram represent the actual orbital paths of the Earth and Moon, yet the line traced by the asteroid represented its apparent motion. In the new version all of the lines represent orbital paths, and hopefully the motion of the diagram itself is clearer. When the roughly circular path of the Earth's orbit is overlayed with the eliptical path of the asteroid, the angle at which they intersect is that shown (albeit fleetingly) in the new diagram. nagualdesign (talk) 23:46, 11 November 2011 (UTC)

I've uploaded a new version of both images. I didn't add the dashed apparent trajectory as 2 lines only confused the issue. I've tried adding in moving grid lines to suggest the motion of the reference frame (at the cost of 114KB, and the lines are almost invisible on the thumbnail). Does that make things clearer? nagualdesign (talk) 08:56, 12 November 2011 (UTC)
 * There's a problem with the new animation in that there is a ghost image of the first frame on all subsequent frames. This problem isn't with the original (full size) image but with the thumbnail and other cached sizes, due to a software fault. I've mentioned it at the village pump and will try to fix it under advisement. nagualdesign (talk) 19:42, 13 November 2011 (UTC)
 * (For me) the grid does not have to wanted effect: Due to the large timestep, it looks like there is just a new grid for every frame, instead of creating the impression of motion. Can this be fixed? --JorisvS (talk) 22:04, 13 November 2011 (UTC)
 * I've upload 2 more images; the animation and the starmap. Hopefully they now work together better, to make things clearer. I've removed the gridlines as they're more trouble than they're worth, I suppose. There's not much suggestion of movement in the animation, if you ask me, but hey ho! Let me know what you think. :-) Regards, nagualdesign (talk) 06:30, 15 November 2011 (UTC)
 * Quite nice. Maybe it would be good to also show the part of the trajectory YU55 has not yet traversed, like is done for Earth and the Moon? --JorisvS (talk) 09:34, 15 November 2011 (UTC)
 * The Earth and Moon have stable orbits, so their paths 'swallow their own tails' so to speak. The orbit of an asteroid like YU55 is easily perturbed, so it's unlikely that it's following the same trajectory as it did on its previous orbit, hence I drew it in a 'trailblazing' fashion. Interestingly, when drawing the line of arrows I noticed that it wasn't straight, but had a kink of about 0.5°. I suppose this is likely to be the effect of YU55's close encounter with the Earth and Moon, rather than just an error in the original plot. It's small perurbations like this that make asteroids' orbits unstable. Thanks for the feedback. :-) Regards, nagualdesign (talk) 17:44, 15 November 2011 (UTC)
 * Yes, I realize that, that's why I worded it the way I did. I just thought it could possibly make it a bit more apparent how the Earth is moving through space. It probably doesn't matter much anyway. --JorisvS (talk) 19:09, 15 November 2011 (UTC)
 * Hopefully the description on the image file page clarifies things; "Orbital paths are shown from the Earth's reference frame. Over the course of the animation (27 hours) the Earth, Moon and asteroid each travel over 2.8 million kilometers (1.7 million miles; 7.4 lunar distances) through space." nagualdesign (talk) 20:25, 15 November 2011 (UTC)

Near Miss
Shooting a rifle from where to miss it by 6 kilometers? — Preceding unsigned comment added by 24.132.75.137 (talk) 13:08, 7 November 2011 (UTC)
 * To quote George Carlin, "It's not a 'near miss' – it's a 'near hit'!" Ihardlythinkso (talk) 18:49, 4 December 2011 (UTC)

Closest Approach?
"This is the closest known approach by an asteroid with an absolute magnitude this bright since 2010 XC15 (H = 21.4) approached within 0.5 lunar distances in 1976." NASA is just trying to show that they were worth the money, but in fact they missed the Asteroid previouly that came half as close as this one only two weeks ago. And/Or, someone was asleep on the job and then woke up and spotted this one, while the missed all the earlier ones. -- 24.79.40.48 20:12, 7 November 2011
 * has an abs mag (H) of 21.9. with (H = 21.4) is brighter!  An object with an abs mag (H) of 22 would be dimmer, not brighter! I have removed your incorrect edition to the article. -- Kheider (talk) 21:44, 7 November 2011 (UTC)
 * Closest approach and luminosity are not at all the same thing. And the addition was factual and referenced.24.79.40.48 (talk) 00:18, 8 November 2011 (UTC)
 * Do not confuse absolute magnitude (based on a fixed distance) with apparent magnitude (based on actual distance). They are different. -- Kheider (talk) 15:10, 8 November 2011 (UTC)
 * Not sure what the point of the above table is, or what the poster is trying to suggest. The higher the magnitude (the number) the dimmer the object. All of the NEOs mentioned are much dimmer than 2005 YU55, therefore the NASA statement is correct. I think the thrust of the statement was to say that 2005 YU55 will be visible (to keen amateurs), whereas previous incidents were virtually invisible. nagualdesign (talk) 21:50, 7 November 2011 (UTC)
 * What the table says is obvious, pretending not to understand it so you can delete it won't work. 2011 UX255 came half as far as 2005 YU55, so 2005 YU55 is not the closest approach, quite simple actually. 24.79.40.48 (talk) 00:18, 8 November 2011 (UTC)
 * [Edit] Kheider has just posted much the same thing above. There was an editing conflict, as well as the table and reference not being properly formatted, so I had to re-edit. nagualdesign (talk) 21:50, 7 November 2011 (UTC)
 * I have Removed the table since it makes adding new questions/comments difficult. -- Kheider (talk) 21:57, 7 November 2011 (UTC)
 * Yes, I nearly did the same myself. It took me about a dozen attempts to get my comment to show up. It was just a lack of ref close tag, a lack of template close brackets and the close table brackets not being on a new line that was holding things up. I had fixed it though. Kudos for deflecting all the bad edits today, Kheider! ;-) Hope you liked my skymap, which is slightly more art than science, to be fair. nagualdesign (talk) 22:08, 7 November 2011 (UTC)

♦ I think your personal interpretation of what NASA is saying is incorrect, everyone in the media is not hyping this as something they can see (very few people have that kind of equipment), it is the closeness of the approach that is being highlighted, as an impact danger. Please stop pretending to be ignorant of that fact so you can get your way. 24.79.40.48 (talk) 00:18, 8 November 2011 (UTC) ♦ Please don't change the topic I started so you can be right about deleting it.24.79.40.48 (talk) 00:18, 8 November 2011 (UTC) ♦ 0.0009 AU /0.0022 AU = 41% of the distance of 2005 YU55's pass. Can't say it any simpler than that. 24.79.40.48 (talk) 00:22, 8 November 2011 (UTC)


 * User 24.79.40.48, with all due respect please watch your mouth. It is a policy of Wikipedia that we all assume good faith. I do not have a vested interest in deleting other people's work, nor did I pretend to not understand what you were saying in order to get my own way. The statement by NASA did not place the emphasis on the bit in bold, as you have done. What they have said is, "This is the closest known approach by an asteroid with an absolute magnitude this bright..." Now, logic would suggest that any counter example that is closer but dimmer is not relevent to that statement. I honestly thought that you had misunderstood the concept of magnitude, as people often do. That would be a simple mistake and I certainly did not mean any offense by suggesting that. Perhaps my interpretation of NASA's intent is incorrect, but it is a fact that the objects in that table, despite approaching much more closely, are still not nearly as visible as 2005 YU55. And what 'everyone in the media' are or aren't 'hyping' something as has little to do with an encyclopedia. I am not 'pretending to be ignorant' of any facts, I am simply trying to help you stop conflating the issues that you have raised. May I also suggest that, in the name of readability, you post your comments/additions after those that preceded it, rather than slotting comments in between. nagualdesign (talk) 01:37, 8 November 2011 (UTC)


 * 2011 UX255 passed 0.0009AU (130,000 km; 84,000 mi) from the Earth on 2011-Oct-28. The object has an absolute magnitude (H) of only 27. That means at the same distance as YU55, UX255 would be fainter (and would be smaller). Many small asteroids have come closer than YU55 or UX255. This article is about a relatively large asteroid (~400 meters) passing near the Earth. It is not about the small 20 meter ones that pass all the time. -- Kheider (talk) 01:51, 8 November 2011 (UTC)


 * To help you understand what NASA were saying, consider that there are countless small objects at all times that not only come close to the Earth, but bounce off the upper atmosphere, or enter the atmosphere and burn up or even survive entry and land on the ground. Nobody 'hypes' these occurrences because they are both common and benign. Contrast that with a very large, usually bright, object passing through the night sky. They do make the news. As NASA stated, 2005 YU55 is the brightest NEO since 2010 XC15. I'm sure that there is some scaremongering going on in the media - that kind of thing sells papers, apparently - but the really interesting thing is that people, albeit those with advanced equipment (there are many), will be able to witness the event for themselves. To claim that NASA missed an asteroid that previously came half as close as 2005 YU55 only two weeks ago, and that they were perhaps 'asleep on the job', is to ignore the fact that very small or very dim objects are almost impossible to track until they are very close. They did in fact spot the objects in question, hence us having the data which you included in your table. If they had missed them completely we wouldn't even be able to talk about them because, for all intents and purposes, they may not have existed at all. I hope this helps. nagualdesign (talk) 02:11, 8 November 2011 (UTC) PS. I see that Kheider has converted your section title to lower-case, as per WP style guidelines. I had done the same thing myself, but Kheider and I keep trying to make edits at the same time! (Or I'm quite slow at typing!) Please do not take offence.

This JPLnews YouTube video explains things. (@1:10) "This is the closest approach by an asteroid that large that we have ever known about in advance." Does that clear things up? nagualdesign (talk) 19:37, 8 November 2011 (UTC)


 * I thought that perhaps I had been wrong about my interpretation of NASA's; that 2005 YU55 will be visible (to keen amateurs), whereas previous incidents were virtually invisible. Having done a few calculations I can confirm that I was correct. 2011 UX255's absolute magnitude is 5.5 'larger' than 2005 YU55's, which equates to a brightness difference of 158.49 (YU55 is 158x brighter). However, because UX255 passed much closer the brightness difference is actually only 26.52 (YU55 is still 27x brighter, even though it is more distant). I haven't completed the calculation for every NEO on the list but can see that none would have a brighter apparent magnitude than 2005 YU55. As has been reported in the media, anyone with a telescope 6 inches or larger will be able to watch the asteroid passing - if only they can keep up with its rapid movement! nagualdesign (talk) 20:58, 8 November 2011 (UTC)


 * 2011UX255 made it's closest approach at 2011-Oct-28 17:42UT. At that time UX255 peaked at about apparent magnitude 14.3. YU55 peaks at apparent magnitude 11.1. -- Kheider (talk) 21:43, 8 November 2011 (UTC)


 * Yes, those numbers equate to a brightness difference of 19.055x (not too dissimilar to my 26.52x), so that also confirms what I had thought. Hope you're enjoying the live feed, Kheider. :-) nagualdesign (talk) 22:06, 8 November 2011 (UTC)

Complaint
♦ First of all, I am taking the uncivil way you two have acted in this disussion page (deleting my topic and comments) to the administration of the site through proper channels. Secondly, a 20 meter wide asteroid is not nothing, and 2011 UX255 passing twice as close to the Earth as 2005 YU55 is also not nothing. It is a false statement to say 20 meter wide asteroids pass by the Earth all the time, NASAs list shows the frequencies are not as disparate as you want us to believe. It is important to note, contrary to media hype of the impact potential of 2005 YU55, that the impact potential of 2011 UX255 was much much greater. A 20 meter wide rock potentially slamming down on your front lawn is very notiable. This Impact Simulation tells a very different story, showing that the energy of the airburst would be 5.63 x 1020 Joules = 1.35 x 10^5 MegaTons. 24.79.40.48 (talk) 13:07, 8 November 2011 (UTC)

Your complaint is noted.
 * Pleas watch your language and tone.
 * Please do not insert OR into the article. 2011 UX255 (~20 meters across) has nothing to do with an article about a 400 meter asteroid passing inside the orbit of the moon. UX255 would be on par with a Tunguska event, and would not create a crater 4 miles in diameter. Many small asteroids have come much closer to the Earth than 2011 UX255 did.
 * Please do not needlessly insert a large table in the main article or the talk page. (I never removed your words just your poorly formatted table from the talk page.) -- Kheider (talk) 15:02, 8 November 2011 (UTC)


 * User 24.79.40.48, of course it is your prerogative to lodge a formal complaint, however I feel that you are again conflating several issues. Re. "Two editors acting like bullies", Kheider and I have never worked together before and acted individually on this occasion. I had made a total of 1 comment (21:50, 7 November) when you accused me first of 'pretending not to understand it so you can delete it' and then 'Please stop pretending to be ignorant of that fact so you can get your way'. I did not delete anything. In fact I had spent quite a while trying to fix the closing wiki-markup of your table so that it didn't have to be removed. When Kheider removed your table (from this talk page) he/she was perhaps unaware that I had corrected the problem. If you perceived this course of events as bullying then I gladly hold myself up to further scrutiny. Re. "Not sure this is worthy of an incident report, but would like a second opinion of the behavior of these two, deleting a valid topic on a discussion page and all the comments seems like vandalism to me personally." As far as I am aware only the section title was renamed (by Kheider) to something more appropriate, possibly less libelous, and no comments were deleted. I had tried to assume good faith myself, and had ernestly tried to help you understand the issues that you raised. It's unfortunate that you could not have the same courtesy. nagualdesign (talk) 19:14, 8 November 2011 (UTC)

Crater? Why?

 * According to Jay Melosh, if an asteroid the size of 2005 YU55 (~400 m across) were to hit land, it would create a crater 6.3 km (4 miles) across, 518 m (1,700 ft) deep and generate a magnitude 7 earthquake.[11] If an asteroid such as (144898) 2004 VD17 (~580 m across) were to impact land, it would produce a crater about 10 km (6.2 miles) wide and an earthquake of 

71% of the Earth's surface is ocean; shouldn't we have an estimate of an ocean impact instead of one on land? Viriditas (talk) 07:41, 8 November 2011 (UTC)


 * I had thought about that, but when I was comparing an impact of YU55 to, only YU55 had a figure for the tsunami created by an water impact. At the time I did not want to get too wordy. -- Kheider (talk) 14:38, 8 November 2011 (UTC)

New images
NASA has new images here: I suggest we update from the suspiciously round, several-month-old image currently used. 75.41.110.200 (talk) 15:56, 8 November 2011 (UTC)

Live images!
I realise that I'm probably breaking several Wikipedia guidelines by posting this, but to all keen amateur astronomers without a 6" telescope who are interested in seeing where 2005 YU55 is right now, visit Slooh.com where you can watch a live feed from the half-meter telescope (and others) on the Canary Islands! (Sorry Jimbo, I couldn't help myself! ...I will remove this post after the event.) nagualdesign (talk) 21:11, 8 November 2011 (UTC)
 * Initial coverage has now ended and will return at 2am (GMT). nagualdesign (talk) 22:43, 8 November 2011 (UTC)
 * You can also check Live feeds on asteroid 2005 YU55 as it passes Earth (The Planetary Society Blog) and Clay Center Observatory -- Kheider (talk) 23:27, 8 November 2011 (UTC)
 * Cool. :-) At the risk of turning this section into a (temporary) forum, what are all the little coloured dots in the background? nagualdesign (talk) 23:56, 8 November 2011 (UTC)
 * Hot pixels in the camera. -- Kheider (talk) 00:04, 9 November 2011 (UTC)

Coverage has now returned on SLOOH.com and, although the images are not nearly as good as the Clay Center Observatory, it includes a live (audio) discussion of the event and phone-ins from experts and the public. (Refresh the page if the audio isn't forthcoming) nagualdesign (talk) 02:55, 9 November 2011 (UTC)
 * Aww! That was an anti-climax. The SLOOH feed ended rather abruptly at 3am (GMT). As the Clay Center Observatory is still going I will leave this section up until tomorrow, when I will remove it as per WP guidelines (unless others disagree). Again, sorry for bending the rules like that. ;-) nagualdesign (talk) 03:07, 9 November 2011 (UTC)
 * I would suggest moving this section to the bottom tomorrow. I doubt the Wikidragons will attack us on the talk page for leaving it here. :) -- Kheider (talk) 03:15, 9 November 2011 (UTC)
 * Okay, will do. There's no harm in preserving this discussion for future historians I suppose! Love the page on Wikidragons, by the way. Very amusing. :-D nagualdesign (talk) 03:43, 9 November 2011 (UTC)

Discrepancy between closest approach and greatest magnitude
At the moment the article, and in particular the trajectory diagram that I uploaded, has the closest approach occuring simultaneously with the greatest apparent magnitude. However this is not the case. Due to the illumination provided by the Sun, at closest approach the asteroid is only partially lit (from Earth's perspective) and does not become more fully illuminated until later, when the viewing angle is improved. Could somebody please tell me what the facts are and I will amend the diagram as necessary. Thanks. nagualdesign (talk) 00:17, 9 November 2011 (UTC)


 * Does your Sky Chart plot the magnitude? I thought it just plotted the position in the sky? -- Kheider (talk) 00:32, 9 November 2011 (UTC)


 * Well, I based my diagram on the GRAS diagrams that you provided a link to, where the brightest magnitudes seem to occur between 21:29 and 23:29 (or perhaps 00:29). The WP article stated that the closest approach would be at 23:32, if I remember correctly (it now states 23:28), so I opted to place the white arrow at that point. The diagram may well be correct, I'm just unsure as the discoverer himself explained on SLOOH.com that the brightest period would occur after closest approach, likening the 2 views to a half-moon and full-moon, and I assumed the difference would be more than just a few minutes. I'm really just trying to take responsibility for a diagram which I provided, as I have more expertise in Photoshop than astronomy. I hope that makes sense! nagualdesign (talk) 00:54, 9 November 2011 (UTC)


 * Yes, the asteroid is coming from the direction of the Sun. So the asteroid will be a little brighter after it passes the Earth and is fully lit. -- Kheider (talk) 02:07, 9 November 2011 (UTC)


 * I was really just wondering how much time would pass between minimum distance and maximum brightness. Having done a little more research I believe that the asteroid is at its brightest about now, so none of the article, including the diagram I provided, is incorrect. (Phew!) It does slightly conflict with the GRAS page, however the GRAS page currently has some rather glaring errors (eg, 'ticks are every 15 minutes'), so I think I'll just leave it as it is. I still have the Photoshop file, which uses layers, if anyone would like me to make any edits in the future. Thanks. nagualdesign (talk) 02:27, 9 November 2011 (UTC)

Re. binoculars and telescopes
I had altered the wording of the paragraph regarding viewing the event with binoculars and telescopes as I thought it implied that the asteroid was rendered invisible due to the glow of the Moon. I had not taken into account the wider FOV provided by binoculars which I can understand may well have made viewing impossible. The paragraph now reads much better (since Kheider's re-edits) but still seems to confuse the issue regarding experts and amateurs. Perhaps the use of terms regarding expertise should be removed entirely. I will leave this to someone else to do (that means you, Kheider!) Also, I still think the {conversion} of lunar distances is unneccessary, as it is already stated in the OP, and at the very least it needs re-working (too many parentheses). Kind regards, nagualdesign (talk) 02:17, 9 November 2011 (UTC)


 * Should we remove the comment about binoculars? I am 50/50 on the idea. -- Kheider (talk) 02:37, 9 November 2011 (UTC)


 * "The asteroid would have been visible to experienced observers using high-end binoculars with an objective lens of 80+ mm if it were not for bright moonlight preventing a true dark sky. Since the gibbous moon did interfere with the viewing, observers trying to visually locate the asteroid required a telescope with an aperture of 6 inches (15 centimeters) or larger." ..Much better. :-) I'd leave the binocular bit. Looks fine now that it isn't confused by experts/amateurs. Regards, nagualdesign (talk) 02:42, 9 November 2011 (UTC)

line in the animation
In the animation, what is the line going through the Earth, down at about a 45 degree angle? Is it the path of the Earth? If so, the asteroid crossed the Earth's path at nearly a 90 degree angle? Bubba73 You talkin' to me? 00:12, 10 November 2011 (UTC)


 * Yes, that is the path of the Earth. But the asteroid does not intersect the Earth's path in 3-D space. -- Kheider (talk) 03:11, 10 November 2011 (UTC)


 * As noted in the Trajectory animation section above, the apparent path of the asteroid (though it did not intersect with the Earth's path) was roughly perpendicular to to the Earth's orbital path. However, the reference frame of the animation follows the Earth, which is moving, therefore the proper path of the asteroid through space is actually closer (in angle) to the orbital path of the Earth - the asteroid orbits the Sun. I have altered the diagram to reflect this, as I thought it was confusing, too. It still is, I guess. nagualdesign (talk) 23:18, 11 November 2011 (UTC)

Swift satellite observed it in UV
Swift Satellite Captures Asteroid 2005 YU55′s Tumbling Flyby could add to the Study section. - Rod57 (talk) 11:14, 11 November 2011 (UTC)

Precise distances (LD)
With regards to mine and Kheider's recent edits (distances in LD), I had taken my information from JPL too (0.00217 AU and 0.00160 AU), although the article was from back in March, so hopefully Kheider's is more up-to-date. The conversion into LD (then kilometers and miles) was then done using Wolfram Alpha. Unfortunately there is some discrepancy between WA and WP which I raised at the talk page, where Frietjes arrived at a figure of 1 LD = 384,403 km. If you (Kheider) are certain that the LDs are now correct perhaps you'd like to deploy the convert template: 0.844 LD and 0.623 LD Kind regards, nagualdesign (talk) 21:00, 15 November 2011 (UTC)


 * Looking at JPL Solar System Dynamics data, closest approach to the Earth was 0.0021720 AU, and closest approach to the moon was 0.001601 AU. Since 0.845 LD will not convert to match NASA's NASA's as close as 324,600 kilometers, it might look funny to over-use a LD-conversion template that can not be quickly verified by the reference. -- Kheider (talk) 22:01, 15 November 2011 (UTC)


 * Hmmm.. Perhaps this has served to highlight a discrepency between the template's figures for AU and LD. I'll mention it to Frietjes, and if and when it can be remedied so that the figures do match up I'll insert the template. I don't think it's a problem if the number (325,000 km) is correct to 3 significant figures, but 148,800 km ≠ 202,000 km! nagualdesign (talk) 23:26, 15 November 2011 (UTC)
 * ..Ignore that last bit, I just spotted my mistake. nagualdesign (talk) 23:40, 15 November 2011 (UTC)


 * NASA have kindly amended their figure. :-) nagualdesign (talk) 18:40, 18 November 2011 (UTC)


 * That is the same reference. -- Kheider (talk) 19:48, 18 November 2011 (UTC)
 * Keep up Kheider! ;-) Yes, that is the same reference. The difference, in case you missed it, is that it used to say 324,600 km and now it says 324,900 km. I sent an email to NASA's Mr Agle (his email address is at the bottom of that page) pointing out the discrepancy and he has amended that page. I'm not sure what you're refering to about OR as the figures were derived from NASA too, remember? I agree that there's too many significant figures shown in the LD measurements, but that's an issue for the template which will hopefully be dealt with there. Please change the figures back and perhaps read this short discussion. Regards, nagualdesign (talk) 23:01, 18 November 2011 (UTC)

I suppose we can go back to 4 sig figs for the moon distance that are not directly quoted by JPL since JPL uses AU and NOT LD.
 * YU55 distances:
 * Earth MIN: 0.00217200419898454 AU
 * Earth MAX: 0.00217204624016578 AU
 * Moon MIN: 0.00160118357991052 AU
 * Moon MAX: 0.00160123773003473 AU -- Kheider (talk) 00:59, 19 November 2011 (UTC)
 * Good one. Glad you didn't feel like I was bullying you! :-P Of course interpreting or inferring from a reliable source is dubious, but a straightforward conversion is still factual. Even translating a quote from one language to another is normally acceptable. Provided that we aim for accuracy and help to make a better encyclopedia it's safe to ignore all rules. nagualdesign (talk) 03:47, 19 November 2011 (UTC)

Another dubious reference?
Hello Kheider! :-) I see that you have edited the Future trajectory section to accurately reflect the reference, which does indeed state:
 * "This asteroid also closely approaches Venus, most notably within 0.0019 AU (0.74 lunar distances) in 2029. The uncertainties will increase substantially afterward, so that by the time of the next potential encounter with Earth in 2041, the asteroid's minimum distance could be anywhere between 0.002 AU and 0.3 AU. Radar astrometry obtained in Nov. 2011 should clarify the Earth encounter situation in 2041 and beyond."

Given that the difference between 0.002 AU and 0.003 AU would itself represent a 'substantial' uncertainty, I would suggest that the quoted distance (0.3 AU) would represent a ludicrous level of uncertainty and is probably a typo - even NASA make mistakes. YU55 will only pass within 280,000 km of Venus (which may need correcting in the article, BTW), which is hardly enough to 'fling' the asteroid into such an unstable orbit as to move its next 'close' encounter with the Earth some 28 million miles more distant. Besides which, 0.3 AU would not even be classed as a 'potential encounter' at all. As with the previous error, it sometimes behooves us to apply common sense rather than sticking rigidly to the principle of verifiability, not truth. The last time I queried NASA they kindly (and silently) corrected their error. Far be it from me to correct NASA twice in one lifetime, so perhaps you would care to email Dr. Benner ([mailto:lance.benner@jpl.nasa.gov lance.benner@jpl.nasa.gov]) yourself and ask him for clarification? I hope that this suggestion is taken with the good intent with which it is given, and of course I may be wrong after all. Kind regards, nagualdesign (talk) 01:31, 26 November 2011 (UTC)
 * ..By the way, Lance Benner is a Trekkie (Check out the bottom of that page). Perhaps you'd like to soften the blow/bridge the divide with a little Star Trek humour. Just a thought. ;-) nagualdesign (talk) 01:48, 26 November 2011 (UTC)


 * I updated most of that data 7 November 2011 when the first radar observations were reported. I have now updated the wording to hopefully better reflect the current known trajectory. -- Kheider (talk) 23:55, 4 December 2011 (UTC)
 * I was a little more concerned about the figure of 0.3 AU to be honest. Considering that NASA have emphatically stated that YU55 won't hit the Earth for at least ~100 years, an 'uncertainty' of tens of millions of miles is surely a contradiction, no? I'll email Dr. Benner myself if you'd prefer not to. nagualdesign (talk) 00:04, 5 December 2011 (UTC)
 * The uncertainty in October was obviously larger than the uncertainty after the November radar observations. It is now known that the asteroid will pass between 0.1017AU and 0.1023AU from the Earth on 2041-Nov-12. -- Kheider (talk) 06:34, 5 December 2011 (UTC)

Hasn't it got to approach Venus in 2029 before we can be certain of anything? Well anyhow, there seems to be very little reason to include an overly complicated paragraph about old predictions which we now have a far better handle on. Better to just stick to what we know now, right? May I suggest this rewrite:


 * "On 19 January 2029, will pass about 0.0023 AU from Venus. This close approach to Venus will determine how close the asteroid will pass the Earth in the future. Radar astrometry in November 2011 suggests that  will pass about 0.102 AU of the Earth on 12 November 2041 and about 0.070 AU on 25 April 2045."

Neither of these would be classed as the next potential encounter with Earth anymore, but both are (similarly) as close as it gets between now and 2075 (when it will approach at 0.0013-0.0042 AU), and much could happen between now and then. nagualdesign (talk) 08:17, 5 December 2011 (UTC)


 * My 7 November 2011 update changed the 2029 Venus encounter from an uncertain 0.0019AU to a solid 0.0023AU. We should not confuse dated predictions with current predictions. I think it is important to keep the history of the old predictions in the article. -- Kheider (talk) 15:37, 5 December 2011 (UTC)

Strange/Puzzling structures
Thanks for your contribution to 2005 YU55. However, I've removed it because the source you were using, BBC, was quoting NASA less than accurately, and your addition made it seem like more than it was. The actual quote comes from radar astronomer Lance Benner at JPL:

"The movie shows the small subset of images obtained at Goldstone on November 7 that have finished processing. By animating a sequence of radar images, we can see more surface detail than is visible otherwise," said radar astronomer Lance Benner, the principal investigator for the 2005 YU55 observations, from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The animation reveals a number of puzzling structures on the surface that we don't yet understand. To date, we've seen less than one half of the surface, so we expect more surprises."

I have no objection if you wish to add similar material back using that source, but the BBC made this out to be something it wasn't. Viriditas (talk) 07:00, 6 December 2011 (UTC)


 * Instead of removing the material and the reference, why not change the wording and insert your reference? Here's another reference. http://www.washingtonpost.com/national/health-science/asteroid-2055-yu55-passes-close-by-earth-how-close-did-it-get/2011/11/09/gIQAdQpw5M_story.html Now we've got the BBC, the Washington Post and NASA all saying the same thing: strange/puzzling structures on the surface. Ghostofnemo (talk) 07:27, 6 December 2011 (UTC)
 * Sorry, I thought I explained why I removed it. I personally don't find it notable to include.  We find "puzzling" things all the time.  It's called "discovery". Viriditas (talk) 07:46, 6 December 2011 (UTC)
 * I've made the modification you suggested, however this might be a problem because we aren't supposed to use primary sources (in this case NASA): "Wikipedia articles should be based on reliable, published secondary sources and, to a lesser extent, on tertiary sources. Secondary or tertiary sources are needed to establish the topic's notability and to avoid novel interpretations of primary sources, though primary sources are permitted if used carefully. Material based purely on primary sources should be avoided. All interpretive claims, analyses, or synthetic claims about primary sources must be referenced to a secondary source, rather than original analysis of the primary-source material by Wikipedia editors." (see WP:PRIMARY) Regarding notability, NASA, the BBC and the Washington Post all found it notable. Ghostofnemo (talk) 07:48, 6 December 2011 (UTC)
 * There's no problem here at all. Lance Benner at JPL is the source for the original quote.  This quote was originally released in a NASA press release and covered by multiple sources.  However, whenever possible, we quote as close to the original science source and avoid misrepresentations which are common in the popular media.  This is standard practice on Wikipedia.  Some projects have put together guidelines to help editors like yourself use scientific sources in the most accurate way possible.  Along these lines, Identifying reliable sources (medicine) and Identifying reliable sources (natural sciences) may help provide some guidance for you in the future.  Although it may seem like "strange" and "puzzling" are synonyms, the way it was used by the popular media and in the context you originally added it, made it seem like NASA found alien artifacts on 2005 YU55 and was covering them up. Viriditas (talk) 08:00, 6 December 2011 (UTC)
 * NASA is a much better source than Space.com, BBC, or the Washington Post. The newspress often gets the details wrong. What was noticed on YU55 were bright features that were most likely boulders on the surface. I will try locating a better source later. -- Kheider (talk) 08:22, 6 December 2011 (UTC)
 * That may be so, but according to Wikipedia, primary sources should be avoided. The BBC and the Washington Post are not tabloids. Ghostofnemo (talk) 04:57, 11 December 2011 (UTC)
 * You were already corrected on this point and provided with links explaining your mistake. Please don't engage in IDHT.  A press release from NASA highlighting and attributing an accurate, direct quote from a scientist never takes a backseat to a newspaper source that sensationalized and misrepresents the original quote.  It you wish to take this to a noticeboard for further discussion let me know. Viriditas (talk) 06:36, 11 December 2011 (UTC)
 * From Identifying reliable sources (natural sciences): "Scientific information should be based on reliable published sources and should accurately reflect the current state of knowledge. Ideal sources for these articles include comprehensive reviews in independent, reliable published sources, such as reputable scientific journals, statements and reports from reputable expert bodies, widely recognized standard textbooks written by experts in a field, or standard handbooks and reference guides, and high-quality non-specialist publications. Although news reports are sometimes inappropriate as reliable sources for the technical aspects of scientific results or theories, they may be useful when discussing the non-technical context or impact of science topics, particularly controversial ones." NASA is a primary source, not a scientific journal or recognized academic body. Ghostofnemo (talk) 03:11, 13 December 2011 (UTC)
 * I'm afraid you haven't understood what you've read nor have you made use of common sense skills needed to understand how to use these sources. The first thing you need to understand, is that NASA is the primary source for the information in question.  Any other secondary source used here is only relying on NASA.  Is that clear so far?  Second, WP:SCIRS is very clear on how we use secondary sources here:
 * "...news articles should be used with caution when describing scientific results, studies, or hypotheses. Science news articles may fail to discuss important issues such as the certainty of a conclusion, how a result has been received by experts in the field, the context of related results and theories, and barriers to widespread adoption or realization of an idea....Articles in newspapers and popular magazines generally lack the context to judge experimental results; be particularly wary of any result reported as surprising or revolutionary, which may be an indication of exaggeration or worse...A news article should therefore not be used as a sole source for a scientific fact or figure, nor should they be considered when describing what aspects of a field the relevant experts consider interesting, surprising, or controversial. Editors are encouraged to seek out the scholarly research behind the news story; good quality science news articles will indicate their sources."


 * Which leads us to the present situation, and your misuse of a secondary source which in turn, misrepresents a quote from NASA. In this particular case, the primary source from NASA is acceptable and superior to the secondary sources.  In order to best apply our policies and guidelines, you need to be able to understand how we use sources and what we look for when choosing the appropriate source to cite.  In this example, a quote from NASA is best cited to the primary press release, since the secondary source has misrepresented the topic.  And, since this topic is notable, the primary source is acceptable. Viriditas (talk) 06:37, 13 December 2011 (UTC)
 * First of all, the BBC and Washington Post are NOT misrepresenting NASA's press release. They are both simply using a different word "strange" to paraphrase the press release which used "puzzling". These are clearly synonymous. Second, a press release is even lower on the reliable source hierarchy than news reports. Please see: http://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_%28natural_sciences%29#Other_sources Ghostofnemo (talk) 06:50, 13 December 2011 (UTC)
 * I'm sorry, but you are wrong. There is a dispute here about the accuracy of the secondary source reporting of a quote from a  JPL scientist.  When such a dispute arises, we go with the original quote; what we don't do, is duplicate the error or continue misrepresenting the source.  The words are not synonymous in this context, because you are attempting to promote and push a conspiracy theory by misusing and misrepresenting these sources.  When such a dispute arises, we go with the original quote to avoid this problem.  Finally, a press release from NASA is in this instance, the most reliable source for our purpose, as they are the original agency that provided the quote and the evidence to the secondary source.  If, for some reason, this was a notable topic, then we would require a secondary source to prove notability, but that is not the case here.  I'm afraid your continuing misuse of sources to push a fringe POV needs to stop. Viriditas (talk) 07:06, 13 December 2011 (UTC)
 * You must be accusing the BBC and the Washington Post of pushing conspiracy theories, because I have only been editing based on what they have reported, and these sources should be included based on my understanding of Wikipedia's guidelines regarding reliable sources. Ghostofnemo (talk) 07:17, 13 December 2011 (UTC)
 * And you have been informed, repeatedly, that those secondary sources do not override the primary quotes which they misrepresented. Please do not continue to push conspiracy theories here. Viriditas (talk) 07:19, 13 December 2011 (UTC)
 * I have gone to great length to explain why the BBC and Washington Post are reliable sources, that the article should be neutral in tone, and should not be based on government press releases. This is not promoting conspiracy theories. Ghostofnemo (talk) 07:30, 13 December 2011 (UTC)
 * You have gone to great lengths to promote a conspiracy theory. When a popular secondary news source misrepresents a quote from an official organization, we default to the official source.  This discussion is now over. Viriditas (talk) 07:33, 13 December 2011 (UTC)
 * And "boulders" on an asteroid? What is holding these "boulders" in place? Certainly not gravity. Ghostofnemo (talk) 05:02, 11 December 2011 (UTC)
 * Ghostofnemo, gravity will keep boulders attached to the surface of the asteroid, esp. if it is a rubble pile built from rocks and boulders. See 25143 Itokawa as an example. Please do not use a writing style that could suggest a fear mongering agenda on Wikipedia. The BBC and Washington Post are not qualified to interpret radar images. -- Kheider (talk) 13:43, 11 December 2011 (UTC)
 * Can you see any of this in the images? For some reason, they are EXTREMELY low resolution when I try to view them, even the supposedly "better" images that were released later, and all I see are blurred pixels. And it's not "fear mongering" - I watched a science program about how astronauts would have difficulty mining asteroids because of the absence of gravity. So if there is not enough gravity to hold an astronaut, how are these boulders being held in place? A rubble pile is not a solid object, and neither NASA nor the news media have describe YU55 as a rubble pile.Ghostofnemo (talk) 03:15, 13 December 2011 (UTC)
 * Last time I checked, boulders did not have legs with muscles that could cause them to push off of the asteroid by accident. The bright spots on the asteroids surface could very well be boulders. (Do you have a reliable source that says otherwise?) There is an infinite number of combinations between a solid rock and a highly porous rubble pile. -- Kheider (talk) 08:27, 13 December 2011 (UTC)
 * The BBC and Washington Post were not interpreting the images, they were reporting what NASA told them while exercising their function as reporters, editors and publishers to determine newsworthiness and accuracy of the story. NASA can release whatever it likes, but those are its own findings, making it a primary source reporting its own original research. Ghostofnemo (talk) 03:21, 13 December 2011 (UTC)
 * I see that all the secondary sources have been deleted once again. Please restore the deleted reliable references. Ghostofnemo (talk) 03:27, 13 December 2011 (UTC)
 * And what is the rationale for this deletion? http://en.wikipedia.org/w/index.php?title=2005_YU55&diff=465593569&oldid=465592596 Ghostofnemo (talk) 06:34, 13 December 2011 (UTC) Please see WP:NPOV. Ghostofnemo (talk) 06:59, 13 December 2011 (UTC)

I think the BBC and Washington Post would not have made exactly the same "mistake", considering their reputations as reliable news sources. They are simply paraphrasing. Besides, we used your wording, precisely the same as the NASA press release, but simply had the BBC and WP as supporting references, but they've been deleted as "low quality" references http://en.wikipedia.org/w/index.php?title=2005_YU55&diff=465285428&oldid=465241886 which seems extremely odd since these are both secondary sources normally held in high regard. Ghostofnemo (talk) 07:45, 13 December 2011 (UTC)
 * As I wrote before NASA worked with Goldstone to do the research science. The BBC nor Washington Post did any scientific research, they just parroted the NASA Nov 8 press release. There is no reason to have 3 referencing saying the same basic thing. You do seem to be trying to push an agenda by downplaying the Nov 11 NASA press release. -- Kheider (talk) 08:17, 13 December 2011 (UTC)
 * You see, that's how Wikipedia is supposed to work. Reliable secondary sources are preferable to primary sources. It's a basic premise. As far as I know, the second press release has not been mentioned by a reliable secondary source. Ghostofnemo (talk) 00:20, 14 December 2011 (UTC)
 * Please take your concerns to the appropriate noticeboard and stop disrupting this talk page. NASA is a reliable source for this topic. End of discussion. Viriditas (talk) 00:19, 14 December 2011 (UTC)
 * I have done so, at: http://en.wikipedia.org/wiki/Wikipedia:Reliable_sources/Noticeboard#Use_of_reliable_media_reports_as_secondary_sources_to_support_primary_sources Ghostofnemo (talk) 00:42, 14 December 2011 (UTC)
 * Oh dear. It's another case of IDHT if you ask me. Paraphrasing isn't appropriate in this situation. nagualdesign (talk) 02:35, 14 December 2011 (UTC)
 * Please see WP:PARAPHRASE. And guess what? Journalists do this too! BTW, the NASA astronomer who was quoted used the words "puzzling structures", Not "puzzling features", "puzzling formations", or "puzzling landmarks". "Puzzling structures" is not a paraphrase, it's a direct quote. Ghostofnemo (talk) 02:07, 20 December 2011 (UTC)

Additions to the article
I have just added a bunch of material to the article, based on work that will be presented at the 2012 Asteroids, Comets, and Meteors meeting in Niigata next month. I've referenced three out of five YU55-related abstracts currently available through the meeting's online schedule. One of those is my own abstract, describing the results of our analysis of the radar data obtained during the flyby. I hope that this does not constitute a conflict of interest. Michaelbusch (talk) 22:09, 9 April 2012 (UTC)

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