Re: Comet deflection capability

From: LukeCampbell (lwcampbe_at_uci.thetrash.edu)
Date: 06/11/04 

Date: Fri, 11 Jun 2004 16:35:55 -0700

David Dalton wrote:
> John Schilling wrote:
>
>
>>In real life, as opposed to Hollywood, the lasers that
>>are most effective at drilling into things are industrial,
>>not military. But this doesn't matter, because...
>
>
> Sorry, I saw an article downstairs in this Earth Sciences
> building on laser drilling and I think it was adapted
> from military lasers. Many things industrial were
> once developed by the military but their are other
> driving forces for research.

There have been tests on using high powered lasers to burn or blast
through rock. One of these used the military's MIRACL experimental
laser to provide the beam. However, this method of drilling is grossly
inefficient compared to mechanical means. If you need to drill a hole
in a comet or asteroid for any reason you'd send up a mechanical drill.
  If you are thinking of using a laser based on earth to drill the comet
or asteroid, forget about it. Laser beams cannot focus well enough at
long distances for that.

>>In real life, the most effective way to divert an asteroid
>>or comet is with a salvo of proximity-fuzed nuclear missiles
>>detonating nearby, not nuclear weapons buried deep inside.
>
>
> Wouldn't the ejecta from the hole act as a jet to
> push the body aside?

Yes, but a nuke detonating in close proximity would cause a layer of the
outer surface of the asteroid or comet to be blasted away at high speed
which would also push the asteroid or comet aside. This has the
advantage that you only have to get the warhead in the vicinity of the
body you are trying to deflect, you don't have to get the warhead inside
of the body.

> Also if there was fragmentation,
> many small impacts is better than one big impact.
> (If a comet was in a thousand pieces a higher percentage
> would burn up before impact, for one thing.)

It turns out, no. For one thing, your fragmented asteroid really isn't
in small peices - it is in several large chunks with a fair number of
medium sized bits. Multiple large chunks would do a better job of
distributing devastation globally than one huge chunk. Many medium
sized chunks would be even worse.

There is also a problem with stuff burning up in the atmosphere. You
see, when stuff burns up, it gets hot and radiates heat. Imagine the
sky so full of white hot streaks from the incandescent comet chunks that
you turn the entire sky into a broiler oven, cooking anything that
cannot take cover and igniting all flammables.

Luke 

-- 
To email me, take out the trash.

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