Talk:99942 Apophis

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• Archive of discussions prior to 01.01.2006
• Archive of discussions prior to 01.01.2009

Misleading Lead-in

The lead-in section of this article is misleading

"that caused a brief period of concern in December 2004 because initial observations indicated a small probability (up to 2.7%) that it would strike the Earth in 2029."

It should say has continued to cause concern from December 2004 until recently and then you can use this article http://www.foxnews.com/scitech/2011/02/10/doomsday-determined-asteroid-apophis-strike-earth/ as evidence for example. Don't belittle the situation.212.219.231.1 (talk) 12:59, 11 August 2011 (UTC)

Russian plans

This article just popped up this morning. Anyone interested in editing this article may find it interesting and may be able to incorporate the information. http://news.yahoo.com/s/ap/eu_russia_asteroid_encounter 98.215.128.112 (talk) 17:55, 30 December 2009 (UTC)

My apologies. Apparently someone has already found and posted the article below. 98.215.128.112 (talk) 17:57, 30 December 2009 (UTC)

Somebody should add this to the article. http://news.yahoo.com/s/ap/20091230/ap_on_re_eu/eu_russia_asteroid_encounter I don't know how and don't want to mess it up. —Preceding unsigned comment added by 67.175.127.171 (talk) 15:35, 30 December 2009 (UTC)

Perminov's statements (in the linked interview) indicate that he was not aware of the low probability of impact, and do not reflect any official decisions by Roscomos - so there aren't really any 'Russian plans' yet. I recommend that we leave this out of the article for the moment. Also please remember that this is the talk page for editing the article about Apophis, not a forum for personal opinions (I removed those posts). Michaelbusch (talk) 19:20, 30 December 2009 (UTC)

I agree and have added it. The news story does not talk about Russian Plans, it merely talks about a statement to look into a possible mission, i.e. it may make plans and is considering that now. This is very relevant and worth reporting, as it comes from the official Russian Space Agency. Its not up to us to interpret that they "are not aware of the low probability." That is not relevant.76.14.42.191 (talk) 20:31, 30 December 2009 (UTC)

Since you insist, 76.14.42.191, I'll let it stay. But I have rephrased the text to be more accurate. Note: I do have a personal bias with this article. I am a member of the team that has been refining the impact probability estimates for the past several years. It is very relevant to me that Perminov has apparently been mis-informed about our work. Michaelbusch (talk) 20:39, 30 December 2009 (UTC)

My 2 cents. -- Kheider (talk) 20:54, 30 December 2009 (UTC)

Thanks for letting it stay and I have no problem with your re-wording of my addition. I can see you are close to the subject, and you are probably right that Perminov has been mis-informed about your work. However, we as editors here need to be careful to merely report and not interject our bias, even if that bias is well informed on the subject. Perhaps Perminov is aware of the probabilities but doesnt want to take any chances, or perhaps its PR reasons that they are talking about this. Lets wait to see if other respected and notable people speak about this latest development, but lets not fail to report on it.76.14.42.191 (talk) 20:56, 30 December 2009 (UTC)

Even if the impact is not very likely, this mission could make a lot of sense. This asteroid would offer a perfect opportunity to practice deflecting a body headed for Earth, so if in a few decades or centuries another body appears that will actually hit Earth, invaluable experience gained during the practice mission will make deflecting it that much easier and cheaper. In other words, since we practice responding to disasters all the time, we could do so here as well. Sourcelat0r (talk) 23:04, 30 December 2009 (UTC)

2013 Pass of Apophis

Novosti 2009-02-25 (http://en.rian.ru/analysis/20090225/120298367.html) says "In 2012, Apophis will pass close enough to Earth, enabling scientists to more accurately calculate its 2029 orbit." If so, ISTM worth giving date and distance of that pass, and of any other comparatively near passes before the important ones. 82.163.24.100 (talk) 18:59, 25 February 2009 (UTC)

See Talk:99942_Apophis/Archive_2#2016_Venus_encounter for more details.. -- Kheider (talk) 19:24, 25 February 2009 (UTC)

Some minor details in the naming section

The statement of Apophis being the most persistent Stargate villain, although in the article Goa'uld characters in Stargate is stated that Ba'al is the longest-running villain in Stargate show. 195.39.74.163 (talk) 17:21, 13 July 2009 (UTC)

The article cites a supporting source. Because of this, the article should be read as asserting that

Although the Greek name for the Egyptian god may be appropriate, Tholen and Tucker — two of the co-discovers of the asteroid — are reportedly fans of the TV series Stargate SG-1. The show's most persistent villain is an alien also named for the Egyptian god." (Supporting source: Bill Cooke (August 18, 2005). "Asteroid Apophis set for a makeover". Astronomy Magazine. http://www.astronomy.com/asy/default.aspx?c=a&id=3434. .)

As that cited supporting source does indeed support the assertion, the article should not be changed to make a contrary assertion; though information about contrary assertions made by other sources (with those sources being cited, of course) might be added to the article. Or, alternatively, perhaps this bit of trivia might be left out of the article. See WP:V, WP:CITE. Wtmitchell (talk) (earlier Boracay Bill) 23:38, 14 July 2009 (UTC)

Could be that at the time of the discovery, The show was still in production. Stargate SG1 ran 10 seasons, and Apophis was a major antagonist for at least the first 4 (possibly 5 or more), while Baal (spelling?) was introduced later on (5th season perhaps?) 24.235.198.91 (talk) 23:25, 2 January 2010 (UTC)

I'm opposed to mixing fiction as a source kinds of references into this article, as it will dilute the perceived quality to many readers. It is more-than-enough to state that the etymology traces to greek, and a rather annoying and irrational distraction to speculate that the discoverers are fans of a tv show; even if this were true, the name of the asteroid is irrelevant to its orbit and properties. The discussion doesn't belong here, but belongs on the page about the tv show -- 99.233.186.4 (talk) 13:32, 16 April 2010 (UTC)

Aldrin Manned Mission Plan

During the lecture for the 40th Apollo 11 Anniversary, Buzz Aldrin proposed a manned mission, here's a powerpoint slide of his which shows it, if someone wants to add something to the missions section: http://www.nasawatch.com/archives/2009/07/buzz_aldrins_on.html —Preceding unsigned comment added by Jafafa Hots (talk • contribs) 10:43, 20 July 2009 (UTC)

Which is it?

"Apophis’s brightness will peak at magnitude 3.3, with a maximum angular speed of 42° per hour. The maximum apparent angular diameter will be ~2 arcseconds, so that it will be barely resolved by telescopes not equipped with adaptive optics."

"On that date, it will become as bright as magnitude 3.3 (visible to the naked eye from rural and some darker suburban areas, visible with binoculars from most locations"

According to the Apparent_magnitude page, the second quote would appear to be the correct one. Does someone want to take a shot at fixing this? —Preceding unsigned comment added by 76.21.3.245 (talk) 12:53, 14 August 2009 (UTC)

The resolving power of a telescope has nothing to do with the limiting apparent magnitude. These are separate characteristics. It is the difference between seeing an object (magnitude) and resolving it as a disc. -- Kheider (talk) 15:08, 14 August 2009 (UTC)

1 in 233,000 chance

I rv'ed an edit showing a 1 in 250,000 chance of a collision. The auto generated link at NEO does show the odds as only 1 in 233,000 (2036-04-13.37; 4.3e-06), but since it is an auto generated page I think it is better if we stay with a human created reference. Besides there have been no new observations of the asteroid since 2008-01-09. -- Kheider (talk) 18:31, 7 October 2009 (UTC)

As per an October 7, 2009 NASA Release, chances of impact in 2036 have been recalculated to be 1 in 250,000. So, I undid your edit and added the reference. Darry2385 (talk) 19:04, 7 October 2009 (UTC)

Ah good. Nice to know the automated program is accurate. :) -- Kheider (talk) 19:28, 7 October 2009 (UTC)

Still better odds than winning the lottery —Preceding unsigned comment added by 98.231.242.193 (talk) 21:28, 24 February 2010 (UTC)

Easter Sunday

The event of 2036 will occur on Gregorian Easter Sunday (Orthodox Easter Sunday will be a week later) - that seems worth mentioning.

Could there be a table of all nearest approaches this century, with brief details including miss distance, visible magnitude, GMT of pass, terrestrial nadir of pass, with uncertainties?

82.163.24.100 (talk) 09:57, 8 October 2009 (UTC)

NEODyS Close Approaches (ref #13) has the info you are looking for. -- Kheider (talk) 10:11, 8 October 2009 (UTC)

You miss the point. Such a table, in a more user-friendly form, should be in the Article. Moreover, the NEODyS table includes only some of the above, and gives later figures with what looks like unreasonable precision. 94.30.84.71 (talk) 10:02, 13 May 2011 (UTC)

The Article indicates a pass or impact at 2036-04-12 - but NEODyS has nothing that year. Why the discrepancy? 94.30.84.71 (talk) 10:22, 13 May 2011 (UTC)

Unless the asteroid passes through the unlikely 2029 gravitational keyhole, the nominal close approach of 2036 will be on 2036-Mar-26 at a distance of 0.324593 AU (48,558,400 km; 30,172,800 mi). -- Kheider (talk) 13:14, 13 May 2011 (UTC)

Effect

Article includes "An impact several thousand kilometres off the West Coast of the US would produce a devastating tsunami." True, no doubt; but why the parochiality? An impact off North Brazil would devastate the northern coast of South America, the Caribbean, the African coast, etc. Better to say something like "A [deep-]sea impact would devastate coasts up to thousands of kilometres away". 94.30.84.71 (talk) 10:22, 13 May 2011 (UTC)

The references says, "The most likely target, though, is several thousand miles off the West Coast". -- Kheider (talk) 13:24, 13 May 2011 (UTC)

Impact risk path

Path of risk where 99942 Apophis may impact Earth in 2036.

I have a question. According to the impact risk there is a path that covers a 20 hour earth turn rate. (I would think the curved path indicates this is a time lag due to how the earth is turned).

At the speed the earth is revolving around the sun how can predictions of the accuracy they are claiming be made? Just wondering. —Preceding unsigned comment added by 207.160.238.250 (talk) 16:08, 21 December 2009 (UTC)

Using Newtonian mechanics, the errors in the known trajectory of Apophis result in slightly different arrival times and impact points. If we knew the exact orbit of Apophis we would know when and where it would hit. When Apophis gets very close to the Earth there will be significant perturbations to the asteroid. -- Kheider (talk) 21:45, 21 December 2009 (UTC)

This seems to be based on this,particularly this and this cited there. Wtmitchell (talk) (earlier Boracay Bill) 01:18, 1 January 2010 (UTC)

It should be noted that this path prediction for a 2036 impact is based upon calculations with an estimated mass from a theoretical model which cannot be accurate without a much better understanding of the exact metalurlgical and geological make-up of Apophis. Further, the 2029 path may well lead to a gravitational deflection, and/or an increase or decrease in velocity, which cannot be accurately calculated without knowing the specific mass of Apophis, and which may completely alter the illustrated path and/or time of the 2036 encounter. I fail to see how this illustration holds any relevence whatsoever. There cannot be any significant degree of certainty until after 2029. The distance Apophis travels means that even slightest error in estimation could convert to a huge change in predicted orbital path.

There are predictions for both 2036 amd 2037 (for an estimated 7 year orbit?). The 2029 orbit is theorized to pass close to a "keyhole" with a 2000ft diameter, Apophis is estimated at 1300ft in diameter, the 2006 prediction has a 2000 mile margin of error...and has anyone considered loss of mass due to outgassing and such? More estimates equal greater margins of error, regardless of scientific method or the theories applied. There is any given number of stellar bodies along the Apophis orbit which could introduce variables that could never be predicted without actually trailing Apophis through it's entire orbit.

There is no need to label this illustration as the prediction for a "Path of Risk" for a period of 20 hours on October 13, 2036, alarming people who may be near to this path for nothing... The illustration does however reflect the possible path of a non-geostationary sattelite traveling counter to the earth's rotation, and is an excellent example of exactly that. Wikipedia is not a soapbox for those looking to justify or finance a trip to space. 24.235.198.91 (talk) 22:10, 2 January 2010 (UTC)

The plot is the intersection of the uncertainty region (points where Apophis can be at that time given our current knowledge of its orbit and all possible perturbations) and the Earth. That is what a 'path of risk' is. 24.235.198.91, I don't have the time to explain all of the details of our trajectory prediction (see Jon Giorgini and Steve Chesley's papers for that), but please understand that this is simply a way to represent the potential impact and nothing more. Regardless of where the path of risk plots on the Earth, the trajectory prediction gives a 0.0004% chance that Apophis will actually be along that line at the time that the Earth is there. Michaelbusch (talk) 19:23, 5 January 2010 (UTC)

Risk path, 2036 or 2037?

This image is used on both elsewhere on this talk page and on the main article, as well as on a few other articles. The filename File:2037 Apophis Path of Risk.jpg indicates that it charts the path of risk in 2037, but the descripion always cites 2036. As 2036 is the greater risk, it seems likely that the file was misnamed. Can anyone confirm the correct year for this image and correct its name or usage? —Preceding unsigned comment added by Sparr (talk • contribs) 05:00, 31 December 2009 (UTC)

It is certainly meant to represent the 2036 keyhole risk (NEO at JPL). -- Kheider (talk) 05:41, 31 December 2009 (UTC)

Impact calculations: solid rock vs. rubble pile

I was wondering how the impact calculations would differ if the asteroid Apophis turns out to be a big rubble pile, its center of mass would change during close approach and rotation rate? Also if Apophis turns out to be a rubble pile that breaks apart on close aproach to Earth,How much more of a threat would it be to multible geostationary satellites? Jalanp2 (talk) 18:26, 8 November 2009 (UTC)

Apophis in popular culture

"In the soon to be released id Software game Rage, the game-play takes place on Earth years after an impact by Apophis.[29]"

Does anyone else think this section is utterly unnecessary (to be kind) in a serious article about Apophis?Rodney420 (talk) 18:37, 12 January 2010 (UTC)

These sections appear in tons of articles. Most of the time the content is rubbish. I think that's true for this particular section also. I've removed it based on the idea that we're trying to develop a quality encyclopedia and "gamevideospot.com" doesn't satisfy the requirements for using reliable sources. Good catch Rodney. Dawnseeker2000 20:31, 12 January 2010 (UTC)

How wide is the "path of risk"?

In the section Possible impact effects, the article says:

The result is a narrow corridor a few miles wide, called the path of risk, and it includes most of southern Russia, ...

This is incoherent. If the path of risk is only a few miles wide, it cannot possibly cover "most of southern Russia", and indeed not more than a few thousand square miles. Someone with better understanding should correct this. —Dominus (talk) 18:00, 6 April 2010 (UTC)

I reworded that bit. Wtmitchell (talk) (earlier Boracay Bill) 04:53, 7 April 2010 (UTC)

Thanks very much. —Dominus (talk) 15:04, 7 April 2010 (UTC)

Basic Data

Curious about the dimension info in the Basic Data section. 1) There's a historical statement that there was an estimate of 450 meters at an unspecified time. 2) In the same sentence, an estimate of 350 meters, without stating that this is the most recent and accurate estimate (is it?) 3) In the summary sidebar, an estimate of ~270 meters, with a References link to a JPL database and a suggestion that the most recent observation in the database is 2008.01.09. I was looking for a statement of highest confidence for the dimensions of Apophis relative to most-recent observations, and am not sure whether I found it. Mvsmith (talk) 14:01, 10 November 2010 (UTC)

Orbit Estimation Methodology

Is a Bayesian or some similar statistical method being used to estimate the object's orbit? Is a standardized method being used by all of the observers presenting estimates of the probability of an Earth impact? (What is the apples/oranges potential in the numbers presented?) Are all of the observations obtained to date used to form a population of observations or are the estimates based on the short arcs defined by each of the sets of observations listed in the article? It would be pertinent to mention the methodology used in each case or at least point the reader to a general discussion of orbit estimation methods used by astronomers. Virgil H. Soule (talk) 07:35, 9 February 2011 (UTC)

Orbit Guesswork

There is no orbit info that I can see in this article for the Apophis asteroid. The articles for Ceres and other larger asteroids show their orbits and also considerable eccentricity in their orbits. Although most Asteroids orbit the Sun in the "Asteroid belt", their paths are also affected by gravitation of Jupiter and Mars and other planets of the Solar system, the paths also affected by thousands of other asteroids gravitation and possible collisions. Although Astronomers track thousands of these objects, there is a margin of error in each track that is multiplied by gravity's positive coefficient (the path of a Apophis sized body is affected by Jupiter and Mars and Earth and Venus but Apophis also affects them and other Asteroids and their altered paths affect Apophis and so on). Other unknowns in Apophis' orbital path range from pressure of Solar wind (Solar flares) to Yarkovsky effect. Gravitation or collision can break up an object, close approach to Earth could fracture Apophis (Jupiter did that to an impacting Comet), sending smaller but still lethal pieces at us. Truth is we still plan on in course correction for our space flights. Radio beacons on the ten thousand objects we now track sounds good, not so when you consider the rate of air traffic control accidents with only a few planes in the sky. And wasn't that figure of a hundred thousand asteroids big enough to wipe us out? Shjacks45 (talk) 09:32, 9 February 2011 (UTC)

The orbit of Apophis is listed in the infobox. Apophis is largely only affected by the Sun+Earth+our Moon+Venus over a short 200 year simulation. The orbit of this asteroid is not known well enough to reliably calculate out beyond ~200 years. The affect Apophis' mass has on other bodies can be ignored in the simulations and Apophis can be treated as massless. If you are truly anal you may also need to consider Earth's exosphere for very close approach simulations. -- Kheider (talk) 11:36, 9 February 2011 (UTC)

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘ See the 99942 Apophis (2004 MN4) orbit simulation from JPL using a java applet at http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=99942;orb=1. Wtmitchell (talk) (earlier Boracay Bill) 04:27, 10 February 2011 (UTC)

Warning!: That is a 2-body (Sun+Asteroid) simulation and can not be used to reliably predict the trajectory of Apophis during/ after a close approach to a planet (3rd body). -- Kheider (talk) 18:20, 16 November 2011 (UTC)

A space test

Just have read the chance part here; of course it would go perfect, as if in its trajectory it will only pass earth, but there is so many more out there. Such an object hitting the moon might be wrong too, depending on it internal makeup. Why not enter this rock as soon as possible use solar sails, or bombs and get it out of our path ?. Seams to me better then visiting the Moon or Mars, so i think this is a nice space test at least rusia takes it serious. (but probaply lack funding). —Preceding unsigned comment added by 84.107.161.119 (talk) 13:12, 11 March 2011 (UTC)

There is no reason to worry about it until 2013 when we know the trajectory better. Guessing is never good science. -- Kheider (talk) 19:27, 11 March 2011 (UTC)

Redirect to make Earth impact

Why not - instead of trying to avoid an impact - redirect the asteroid orbit to make a trial Earth impact? The asteroid is relatively small and the consequences of hitting an uninhabited area would be limited. By doing this, we would test both: the methods of changing asteroid path (possibly many different methods) and the real phenomenon of the encounter. Land rather than sea destination would be selected to avoid tsunamis. We are still on time and all scenarios may be contemplated. Ads on live transmission and first row ticket prices would be skyrocketing, anyway.

That's a good one. What if we manage to slightly change its course and cannot correct it enough to have it impact non inhabited land? I think the cameramen for the live transmission on the first row ticket viewers won't be too happy if it turns out they are too close to the impact... =/

Xionbox^₪ 07:54, 19 April 2011 (UTC)

Stabilize Orbit for Luna II?

With a bit of calculations and some rockets out there they might be able to change the trajectory into a stable orbit around the earth, and close enough to be readily used as another Space Station. If it were to have viable resources within it, then the hollowed mining shafts can easily be used for living space when no longer being worked. Not only that, but the shell of the Asteroid itself would be a perfect shield against Micrometeorite impacts. I think it's a good idea, but I don't know if anyone is seriously considering the project. 207.216.58.59 (talk) 08:16, 2 September 2011 (UTC)