But if you break the tether halfway down the bottom half falls at 16,000 mph right? And then it’s burning and then it cracks like a whip. I don’t know about extinction, but not a fun time for anyone.
Aren’t they talking about a mess up on the asteroid trajectory? There is no way a space elevator cable snapping wipes out all life on earth, although I’m sure any populated areas it hits would be quite devastated.
A falling elevator would not wipe anyone out. They would place a protective balloon containing approximately 5 quadrillion tons of gas beneath it. The elevator would be paper thin and a couple of meters wide in the middle where it needs to be strongest. The parts that don’t burn will flutter and slowly fall to the ground.
might be a good idea to have it (explosively?) disconnect it's segments if it's found to be broken. You'll spread the impact but avoid something like a whip crack.