[ExI] Asteroid on track for possible Mars hit

[ben]

"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.

ben zed