[ExI] Asteroid on track for possible Mars hit

[Gary Miller]

Eugene said: >> Much more interesting: when you nuke a rock in space with a
0.5 MT device, how much will you flash-vaporize, and just how much momentum
does that carry, assuming the stuff is 3-6 kK, and how much would that
deflect the impact, given few weeks until impact? Modeling the gravitation
well of the Earth for capture analytically sounds like quite a bitch. A
simulation is perhaps in order. >>

Wikipedia mentions:  >> Tsar Bomba device: 50 Mt - USSR, most powerful
explosive device ever, mass of 27 short tons (24 metric tons), in its "full"
form (i.e. with a depleted uranium tamper instead of one made of lead) it
would have been 100 Mt. >> 

If we have weapons that are 200 times more powerful, why would we limit
ourselves to a 0.5 MT device?

If a blast of this magnitude was to occur at surface level.  How much rock
mass would be converted directly to plasma.

Another possibility to further reduce the mass and force smaller
fragmentation would be to hit it from both sides at once with two
synchronized maximum blasts.

Would such a blast have any effect on the forward momentum of the remaining
mass?

The Mars asteroid is estimated to be moving 8 miles a second.

Assuming we had the same 2 week notice we had for Mars and it took us a week
to put in place our defense, deflection would probably not be option.

Would hitting it head on repeatedly (assuming it didn't break up) negate
enough of the mass and forward momentum to make it significantly less
dangerous.   

Also most websites simply state the size as similar to the one that hit
Russia (coliseum sized).  But is that considered a small asteroid, medium,
or large?

In short if we were to plan for a realistic planetary defense what quantity
of mass should we be able to vaporize?