The formula for volume is with the radius cubed, which you clearly used but didn't write above. A more realistic mass for an asteroid is probably around 1 gm/cm3, but the much bigger factor with kinetic energy is the speed, of course. In this case it can range from a low of 11 km/s to a high of 72 km/s (much higher than the number you used). Taking the worst case situation for both speed and mass, we get a collision energy of around 1025 J, or 2 billion megatons of TNT. Not a good day to be around.Following the link to the Permian extinction, we are given asteroid “as big as Everest” estimates from 6 to 12 km diameter. This ( V = 4/3 x pi x r*2 ) which calculates from 112.8 to 902.5 cubic kilometers, a wide range. Supposing it to be of granite, density ~ 2.7 grams per cc, the mass ranges from 3.05 x 10*11 to 2.44 x 10*11 tonnes.
Asteroids striking the earth move from 13.5 to 17 km/sec. Kinetic energy is e = mv*2. So low mass x low velocity estimate is 5,56 x10*13 ; high mass x high velocity is 7.05 x 10*14. Units are tonne x km*2 / sec*2, and I don’t know what that is, much less what 7 million billion of them are. Megatons, based on the force of detonating a ton of TNT is a totally inadequate comparison.
However, there is a 500 km wide crater in Wilkes Land thought to be contemporaneous with the Permian extinction, ICMYI.
Statistics: Posted by Chris Peterson — Wed Aug 07, 2024 10:01 pm — Replies 7 — Views 302