[ExI] Asteroid on track for possible Mars hit
benboc at lineone.net
Sun Dec 23 23:04:45 UTC 2007
"J. Andrew Rogers" <andrew at ceruleansystems.com> wrote:
> On Dec 22, 2007, at 2:31 PM, Gary Miller wrote:
> > Also if the blast directly destroyed the asteroid and the resulting
> > small
> > debris burnt up on entry into our atmosphere.
> > Would the radioactivity created by the blast create a serious threat
> > when it
> > burnt up in the atmosphere?
> We did plenty of atmospheric nuke testing in the mid-20th century. If
> that was not a serious threat, the posited scenario certainly is not.
The radioactivity is not the problem, it's the "burnt up on entry" bit
that's the problem.
Breaking an asteroid up into small pieces, all still coming in at many
km/sec, would dump an enormous amount of heat into the atmosphere, very
quickly. I suppose you could say the sky would explode.
If we couldn't deflect a big asteriod, it would be far better to let it
hit intact, and take our chances. At least /some/ people might survive
that. I'm sure some of you maths-savvy folk could easily work out just
how toasted we'd be if a 100-km rocky asteroid going at say 10 km/sec
was turned into grapeshot and dumped all it's energy into the atmosphere
as heat and pressure.
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