Board Thread:Wiki Management/@comment-27123758-20190314010201/@comment-25603146-20190413213015

"20 KM is usually the horizon considering clouds are visible from way further away since they're a bit off the ground"

...I definitely feel like I knew that at one point

More specifically, 19.6 km was the radius we assumed at one point, I think. Since nothing else about the equation would change, I can just multiply the r in πr^2 by (19.6/4.7) = ~4.17, and thus the other result by 4.17^2, to get 3.8617e+16 Joules, or ~9.23 Megatons of TNT.

That better, @Spinoirr, @DMUA?