Apophis chances to hit earth dramatically increased!

robnissen · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Just thinking would NASA really tell us anyway, A few people have asked me if they would really tell us if it was going to hit, to stop world panic, people would stop going to work, shops being raided, and theres nothing they would be able to do to bring peace back. I remember when it was all over the news even my family started to panic!  So maybe nasa only said it wasn't going to hit to stop world panic. And a smart 13 year old figured it out!  Just a thought, Please don't rip me apart   Posted by Jem</DIV>Perhaps "just a thought" but its a bad thought.  First, it is unlikely that 1 in 450 odds thirty years in the future would cause a panic.  Second, the calculations are not that hard, the data is out there numerous people can check the calcuations, as this 13 year old boy did (albeit he got it wrong).  Third, from a selfish perspective what better way for NASA to get a monstrous increase in funding, than if there was a legitimate chance that civilization could be threatened by a space rock.  Fourth, related to the third, with a 30 year head start, there are many things that could be done to attempt to lower the odds from 1 in 450.  If the odds were 1 in 450, once those odds were confirmed, it would be in NASA's interests, not to mention humanities, to scream that from the mountain tops.

Jem · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Perhaps "just a thought" but its a bad thought.  First, it is unlikely that 1 in 450 odds thirty years in the future would cause a panic.  Second, the calculations are not that hard, the data is out there numerous people can check the calcuations, as this 13 year old boy did (albeit he got it wrong).  Third, from a selfish perspective what better way for NASA to get a monstrous increase in funding, than if there was a legitimate chance that civilization could be threatened by a space rock.  Fourth, related to the third, with a 30 year head start, there are many things that could be done to attempt to lower the odds from 1 in 450.  If the odds were 1 in 450, once those odds were confirmed, it would be in NASA's interests, not to mention humanities, to scream that from the mountain tops. Posted by robnissen</DIV>Yea good point, but wouldn't it also be best to keep it quiet if they knew it was going to hit and are already working on something, but wouldn't tell the public incase it didn't work?  <div class="Discussion_UserSignature"> “That intelligent creatures exist in outerspace is proven by the fact that they have not contacted us.” </div>

MeteorWayne · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Yea good point, but wouldn't it also be best to keep it quiet if they knew it was going to hit and are already working on something, but wouldn't tell the public incase it didn't work?  Posted by Jem</DIV> You missed the point. Even if we assume for a minute that NASA would withhold f information, how do you stop all of the world's astronomers from speaking up. There's a lot of them out there. The same calculations are done by NEODyS, and many others.You can't hide an asteroid once it's been seen.  <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Jem · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>You missed the point. Even if we assume for a minute that NASA would withhold f information, how do you stop all of the world's astronomers from speaking up. There's a lot of them out there. The same calculations are done by NEODyS, and many others.You can't hide an asteroid once it's been seen.  Posted by MeteorWayne</DIV> good point didn't think of that   <div class="Discussion_UserSignature"> “That intelligent creatures exist in outerspace is proven by the fact that they have not contacted us.” </div>

MeteorWayne · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'> good point didn't think of that   Posted by Jem</DIV>One other thing, we are discovering near earth asteroids at a dizyying pace, and very small ones at that.During the first 2 weeks of April at least 250 were discovered including 4 in the 10 to 75 meter (pretty small) size range that came closer to earth than 10X the lunar distance.It's much harder for an asteroid to sneak up on us than it ever has been, especially a large one. That's not to say it can't happen, one coming from the helion (sunward) direction can still get real close before being spotted. But we've never been as safe as we are now. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Apr 17, 2008

The next object on the JPL risk page with any chance of hitting earth is 2006 CD. It has a 6 in a billion chance of impacting earth about 0 UT July 12, 2008. It's over 200 meters in diameter.The orbit is VERY poorly known, only 12 observations over 2 days in early February 2006.The uncertainty is so large, that based on the most likely orbit, it will be on the other side of the solar system on that date, but due to the very short observational period, it could be almost anywhere. In fact, it would not be surprising at all that one of the several thousand asteroids discovered this year is actually the same object. It's in a highly eccentric, ~ 2 year orbit with perihelion just outside earths orbit, and aphelion well outside Mars' orbit.If it is rediscovered, I'll be sure to post an update. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Jem · Apr 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The next object on the JPL risk page with any chance of hitting earth is 2006 CD.It has a 6 in a billion chance of impacting earth about 0 UT July 12, 2008. It's over 200 meters in diameter.The orbit is VERY poorly known, only 12 observations over 2 days in early February 2006.The uncertainty is so large, that based on the most likely orbit, it will be on the other side of the solar system on that date, but due to the very short observational period, it could be almost anywhere. In fact, it would not be surprising at all that one of the several thousand asteroids discovered this year is actually the same object. It's in a highly eccentric, ~ 2 year orbit with perihelion just outside earths orbit, and aphelion well outside Mars' orbit.If it is rediscovered, I'll be sure to post an update. Posted by MeteorWayne</DIV> This is my worst fear the human population wiped out by one of these things. I have been to NASA 4 time I saw the space shuttle atlantis take off, I always used to have the same dream am stood on a hill looking down at the town and the <span style="border-collapse:collapse;font-family:'LucidaGrande';font-size:11px;white-space

re;-webkit-border-horizontal-spacing:2px;-webkit-border-vertical-spacing:2px" class="Apple-style-span">asteroid hits the city centre, And I see the impact and the wave of debris heading towards me then I wake up before it hits scares the life outta me everytime!  <div class="Discussion_UserSignature"> “That intelligent creatures exist in outerspace is proven by the fact that they have not contacted us.” </div>

MeteorWayne · Apr 22, 2008

This should not be your worst fear.It is far more likely we will destroy our environmentbefore an asteroid whacks us.It's hard (but not impossible) for one to sneak up on us.Worry about water shortages, flooding, heat waves, famine.If an asteroid sneaks up, we won't suffer as much.  <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

DrRocket · Apr 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The JPL impact risk page info on Apophis has not changed as of now....It is the second most likely impactor in this century. The odds are  1 in 45,454.I''ll keep an eye out to see if there's any change.I'll keep an eye out for any update. To me, the odds of impact with a satellte affecting the trajectory significantly seem far fetched. ...Posted by MeteorWayne</DIV>Do you know the methodology by which they quote "odds" of impact.  I assume that this is some sort of error analysis based on uncertainties in the orbital parameters of Apophis, and perhaps in the multi-body dynamical model for the solar system.  My question is whether they have any real knowledge of the distribution of the random variable representing those parameters and whether that knowledge is used in some sort of Monte Carlo simulation in the analysis of the orbital trajectories.  Do they simply assume the distribution is normal (if so how do they come up with the variance) ? Uniform ?  Is a Monte Carlo simulation used or even practical ?  <div class="Discussion_UserSignature"> </div>

MeteorWayne · Apr 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Do you know the methodology by which they quote "odds" of impact.  I assume that this is some sort of error analysis based on uncertainties in the orbital parameters of Apophis, and perhaps in the multi-body dynamical model for the solar system.  My question is whether they have any real knowledge of the distribution of the random variable representing those parameters and whether that knowledge is used in some sort of Monte Carlo simulation in the analysis of the orbital trajectories.  Do they simply assume the distribution is normal (if so how do they come up with the variance) ? Uniform ?  Is a Monte Carlo simulation used or even practical ?  Posted by DrRocket</DIV>THey use various methods depending on the uncertainty of the orbital parameters.Here's the JPL explanation, lots to read, I'm sure you'll like it

http://neo.jpl.nasa.gov/risk/doc/sentry.html <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Saiph · Apr 27, 2008

I'm suprised anybody took the initial article seriously.  It's one thing to claim a kid re-did the math and came up with a different answer, (and to claim he's correct).  That I might buy.But to claim the reason is the object might collide with one of 40,000 other objects....okay.  Now I'm scratching my head.  Then to claim that after such a collision the odds drop down to 1/450...Frankly, once you throw in the collision, the odds become basically incalculable as you've no idea how the collision worked out and changed the orbit.  <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

derekmcd · Apr 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm suprised anybody took the initial article seriously.  It's one thing to claim a kid re-did the math and came up with a different answer, (and to claim he's correct).  That I might buy.But to claim the reason is the object might collide with one of 40,000 other objects....okay.  Now I'm scratching my head.  Then to claim that after such a collision the odds drop down to 1/450...Frankly, once you throw in the collision, the odds become basically incalculable as you've no idea how the collision worked out and changed the orbit.  Posted by Saiph</DIV>I think the reasoning behind this (and I'm only guessing here) is that due to the sheer speed of Apophis, any collision would, likely, be head on versus a satelite impacting Apophis from the side.  Any head on collision could slow it down enough to allow Earth's gravitational pull more time to affect it creating a trajectory we would like to avoid.  <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

Saiph · Apr 28, 2008

That might work but a) you don't know the mass of the other object...which  can make a big difference.b) The article said it "might" impact with one of 40,000 objects... we're not sure its going to hit the earth let alone any smaller object.  To say that such a collision increases the odds are...well, hard to swallow without a lot of extra explaination. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

DrRocket · Apr 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm suprised anybody took the initial article seriously.  It's one thing to claim a kid re-did the math and came up with a different answer, (and to claim he's correct).  That I might buy.But to claim the reason is the object might collide with one of 40,000 other objects....okay.  Now I'm scratching my head.  Then to claim that after such a collision the odds drop down to 1/450...Frankly, once you throw in the collision, the odds become basically incalculable as you've no idea how the collision worked out and changed the orbit.  Posted by Saiph</DIV>I took a look at the site suggested by Wayne -- thanks Wayne.  What I take away from that is the probability of impact collisions are based on a parametric study of variability in observed orbital parameters with a sophisticated solar system model that includes the sun, all of the planets and a few major asteroids.  They do an initial linearized calculation and then if things get serious follow up with a full non-linear Monte Carlo simulation.  This is about what I expected to see.Now if some kid did that calculation, it would have to be one hell of a smart kid with a monster computer and a very sophisticated and detailed mechanics model.  I don't think so -- not outside of the movies.I also tend to agree with you on the effect of a collision.  The uncertainties in orbital parameters after a collision, any collision, ought to dwarf the uncertainties prior to the collision.  I would take any post-collisions probability of impact assessments with a grain of salt -- a train car load of salt. <div class="Discussion_UserSignature"> </div>

DengarReturns · Apr 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>NASA debunks it officially:  http://www.nasa.gov/home/hqnews/2008/apr/HQ_08103_student_asteroid_calculations.htmlNASA Statement on Student Asteroid Calculations WASHINGTON -- The Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., has not changed its current estimates for the very low probability (1 in 45,000) of an Earth impact by the asteroid Apophis in 2036.Contrary to recent press reports, NASA offices involved in near-Earth object research were not contacted and have had no correspondence with a young German student, who claims the Apophis impact probability is far higher than the current estimate.This student's conclusion reportedly is based on the possibility of a collision with an artificial satellite during the asteroid's close approach in April 2029. However, the asteroid will not pass near the main belt of geosynchronous satellites in 2029, and the chance of a collision with a satellite is exceedingly remote. Therefore, consideration of this satellite collision scenario does not affect the current impact probability estimate for Apophis, which remains at 1 in 45,000.    Posted by Philotas</DIV> That's all well and good.  But its also completely beside the point.  In my original post, I clearly stated that NASA had already debunked the kid.  But what interests me (and MeteorWayne seems to agree) are NASA's own statistics about it on their Near-Earth-Object page which seems to say that truth be told, we really don't know yet.  Is that correct?  *updated* Also, even if Apophis only passes extremely close to Earth in 2036, what affects (if any) would that have on us?-Just so you know, I am going to keep asking this, either until I get a satisfactory answer, or I die.  And in the case of the latter, if its at all possible I will do my best to haunt Space.com.  <div class="Discussion_UserSignature"> </div>

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Apophis chances to hit earth dramatically increased!

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