Billiard Ball Strikes Mr. Bloom [name is from Asimov's story]
As the outermost electron shells of the billiard ball come in contact
with outermost electron shells of Mr. Bloom, both are ripped from
their nuclei and scattered in all directions, their kinetic energy
spread roughly equally. Billiard ball's nuclei continue in their
forward momentum relatively unimpeded. As more of billiard ball's bulk
barrels into Mr. Bloom, same fate befalls more atoms. By the time the
billiard ball has travelled its own diameter into Mr. Bloom (1/5 of a
nanosecond), about 1/2000th of its mass (i.e. all electrons and
roughly equal amount of Mr. Bloom's electrons) are exploding outward
with kinetic energy... well, divide billiard ball's mass (typically
160 grams) by 2000 and pick your relativity factor. Certainly enough
to va****ize Mr. Bloom and everybody in the billiard room.
Meanwhile the billiard ball's nuclei keep on going, diverging now that
we have what amount's to 160 grams of fully ionized matter. Electric
repulsion alone would make it explode with enormous force -- and it
is, -- but nuclei are flying apart much more slowly than their forward
momentum, so you can think of them as a spreading cone of incredibly
dense ionizing radiation. Some of the billiard ball's nuclei collide
with Mr. Bloom's nuclei, adding (trivially, in comparison) to the
electron-cloud explosion, and creating a (far from trivial) shower of
secondary radiation. Remaining nuclei hit atoms in the air, the far
wall, the rest of the building, and the air outside -- creating a
spreading cone of blinding light, heat, and truly stupendous secondary
radiation. Since nucleus crossection is about 10^(-10) that of an
atom, all of billiard ball's nuclei will undergo collisions and
release their energy if their spreading cone intersects roughly 10^10
* 0.16 kg = 1.6 million tons of matter.
If the ball is aimed above horizon, this will not happen, and most of
the billiard ball's kinetic energy will escape into space. Still,
being anywhere within sight of the radiation cone will be extremely
unhealthy. If the ball is aimed downward, even at a slight angle, than
all or almost all of the billiard ball's kinetic energy will release
in a monstrous explosion.
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