Re: Earth-grazing asteroids as a military resource

On 3/5/2025 3:02 AM, Martin Brown wrote:

Timing is everything in orbital dynamics.
 The Earth is moving along it's orbit at 30km/s and the impactor is similar or possibly faster depending on its orbital parameters. IOW just a couple of minutes difference between a direct hit and a miss.
 Its actually better than that since glancing impacts will skim off the upper atmosphere like a stone does off off a pond. And only iron or stone ones coming in at relatively steep angles get to reach the ground. Many are loose aggregates of ice and pebbles that disintegrate on entry.
 Earth also spins at 1000 mph at the equator which further complicates timing if you want to hit an actual specific coordinate on the globe.

A more interesting approach would be to install a mass cannon on the Moon.
The math is considerably simpler and there appears to be plenty of
"surplus rock" to use as the source of mass!  :>