[ExI] Asteroid on track for possible (probability of 1:25) Marshit

[Kevin H]

On 12/31/07, Eugen Leitl <eugen at leitl.org> wrote:

>
> A global array of smallish instruments hooked up to
> the Internet would be cheap.


That's the other thing I was wondering: to what extent can the amateur
community play a role in the detection of NEOs.  I think, for one, they'd
have to be using the same online database, maybe NASA's NEO program can in
some way open up their database to include reports from amateurs (perhaps
with some sort of trust metric so that only reliable reporters are treated
seriously).  But, I guess my reservation with this approach is that many
asteroids which are significant from a planetary security perspective are
both relatively small (2007 WD5 is itself only 160 feet long) and dark*,
that is they don't reflect a lot of the sunlight that falls on them (I can't
vouch for other forms of radiation).  So the question is, to someone who
knows more about this than I do, what are the chances that a NEO would be of
a higher magnitude than earth bound "amateur" telescopes can detect?

Also, looking at the orbital diagram of 2007 WD5 (
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007WD5;orb=1, warning Java applet),
it has what I'd call a rather constrained orbit, it stays between the orbits
of Earth and Jupiter.  I suspect that most of the objects in the NEO
database are like this simply because of our location bias: brighter objects
that move quickly in our field of view are more likely to be detected and
orbits calculated than fainter objects that move slowly.  So this might
necessitate spacecraft sent even into the outer solar system.  But then, the
counterargument might be that when the objects get closer we'll detect them
and calculate their orbits soon enough to do something about it before there
is a planetary risk.  I don't know which it is but I thought I'd just throw
some arguments out there to be analyzed by others in the know.

And, of course, all of this needs to have a cost-benefit analysis.  Since
this is really just a chat list, we might want to keep the nitty-gritty
serious talk to the professionals :)

Anyway, thanks,

*Kevin*

* According to Wikipedia, "By the time it arrives at Mars it will have an
apparent magnitude of roughly +26 and will appear over 100x fainter than at
the time of discovery."  According to also Wikipedia (
http://en.wikipedia.org/wiki/Apparent_magnitude), the faintest objects that
even the Hubble space telescope can see is magnitude 30.  This is all just
quick research on the internet.  Given this, I do find it questionable what
earth-based optical telescopes can really do on this front.  Of course, I
haven't explored the possibilities with radio, x-ray, or infrared
telescopes.
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