[meteorite-list] Scientist Warns Massive Asteroid Could Hit Earth in 2182

From: Richard Kowalski <kowalski_at_meteoritecentral.com>
Date: Wed, 28 Jul 2010 20:15:45 -0700
Message-ID: <4C50F261.20900_at_lpl.arizona.edu>

Sterling K. Webb wrote:
> List, Greg, Richard,
>
> The study Fox News is citing may be a new
> one or it may be this one from a year ago,
> (one author of which is Sansaturio), which
> is downloadable at:
> http://arxiv.org/abs/0901.3631
>
> 101955 1999 RQ36 has a poorly determined
> composition and shape. It has been frequently
> considered for an asteroidal mission (including
> Osiris) as it is very easy to reach (low delta-v).
> We could go kick its tires...



Of course I'd like to see Osiris pass through the next round of proposals and
eventually fly. It is an LPL mission.


>
> As of observations through 2006, the odds of
> a 2182 impact are rated at 3570-to-1:
> http://neo.jpl.nasa.gov/risk/a101955.html
>
> While I am no defender of Fox News, please note
> that somebody, presumably Sansaturio, got
> FOX NEWS of all people, to not only mention
> but correctly define the Yarkovski Effect!


Maybe, or they picked it up from their sister tabloid Murdoch publication The Sun.
Even a blind squirrel finds a nut now and then.

>
> The end of the world may indeed be near...


Or not.


>
> Usually a change in odds means only that the
> ellipse of uncertainty has necessarily become
> larger. Paradoxically, while the odds of an impact
> go up, so does the uncertainty of any particular
> outcome.

Yes at first, but this isn't because the encounter ellipse grows. It usually
means that the ellipse become more constricted, but shifts to a more specific
part of the globe. Additional observations constrain the ellipse even more, but
shift it beyond one earth radius.


>
> It's not a party we'd want to miss the invitation
> to, as the impact energy is 2700 Megatons. As for
> waiting until the probability is 100%, Richard, you
> have to realize that to many people that means
> waiting until it's a week away. That's not the
> message we want to send, is it? (Keep that
> funding coming.)

Of course, and obviously the funding question is not missed on me. However, no
one is served by sensationalistic reporting. A realistic approach is to continue
optical and radar observations as the orbital mechanics allow, and then fund and
launch the OSIRIS-Rex sample return mission. In this case having a spacecraft
there will do more to confirm or exclude the impact threat. If it is confirmed
no later than 2022, we'd have 175 years to determine what to do to avert an
impact and then actually go and do it.


>
> NASA put 1999 RQ36 on the Sentry Risk page
> at #2, trailing long time favorite 1950DA: "The
> second object, (101955) 1999 RQ36, currently
> has non-zero impact probabilities on numerous
> occasions during the years after 2165. This is
> analyzed in a paper published by Milani et al.
> (Icarus, Vol. 203, pp. 460-471, 2009), which is
> available as here..." But that link is broken.
>
> Maybe it's at No. 2 with a bullet...
>
> As for cumulative probabilities, nothing in
> this kind of orbit persists for more than a few
> million years, maybe ten million years, so the
> probability that it hits either the planet whose
> orbit it crosses or, less likely, an object in a
> similar orbit is, in the long term, always 100%.
>
> We, however, are just going to hope that the
> folks up in 2150 have a better handle on it
> than we do, aren't we? (I include an exception
> to this last crack for Rob Matson and you,
> of course.)
>
> As for me, much as I'd like to, I do not think
> it's time to dig out that old DVD of "Armageddon"
> or order enough beer for the Impact Party.
>
>
> Sterling K. Webb



The main point of what I wrote was not to discount any and all threats,
including the minor threat that (101955) 1999 RQ36 potentially poses. Instead to
offer an opinion (common in the field) that the media makes much too much about
impact threats that almost always disappear rapidly. We've seen many times in
the past that even before the story makes the rounds in the media, the threat
has been excluded. My advice still holds; If you see something about an impact
threat in the general media and it is anything less than a 100% certain. Grabs
some drinks, snacks and pop Deep Impact in the DVD player. It is better than the
crap ball Armageddon, but not by much. Better still, forget both of them and go
have some adult fun with your partner. THAT is a much better way to spend the time!


More about OSIRIS-Rex can be found in this release when it was selected as a
finalist space mission last winter:

http://www.lpl.arizona.edu/spotlight.php?ID=61

-- 
Richard Kowalski
Catalina Sky Survey
Lunar and Planetary Laboratory
University of Arizona
http://www.lpl.arizona.edu/css/

Received on Wed 28 Jul 2010 11:15:45 PM PDT