4 ms·
Certainly a great deal of energy is released. However, on the time scale of an impact, heat doesn't diffuse in rock very far. Even on the time scale of reentry
by pfdietz 4mo ago
Certainly a great deal of energy is released. However, on the time scale of an impact, heat doesn't diffuse in rock very far. Even on the time scale of reentry to an atmosphere heat doesn't diffuse far. It's common for a meteorite that has fallen to Earth, despite the surface having been melted and ablated, to have an inside that is still freezing cold.
- stackghost 4mo agoAh, this was the piece I was missing. I assumed the heat of impact and/or re-entry would sterilize just about anything that wasn't an engineered heat shield.
- pfdietz 4mo agoThe concern in the impact is how much heat is produced in the material itself, by the shock wave. A shock wave is dissipative, producing entropy and heat as it propagates, but near the spalled surface it cancels itself out and the heating becomes small.
- pfdietz 4mo agoYou might also be interested in the story of Lew Allen's Balls (which is much less prurient than the name might suggest). These were pumpkin-sized steel spheres, coated in a thin layer of graphite, that were suspended as close as 10 meters from one of the Teapot nuclear explosions (22 kT) in Nevada. The explosion vaporized about 1 mm of graphite but otherwise didn't damage the spheres much at all. https://www.youtube.com/watch?v=by1xpy8ob8E https://www.youtube.com/watch?v=by1xpy8ob8E (starting around 5:50).