Hits that big are as bad as a general nuclear conflagration. Very few humans survive, in the long run.
“Hits that big are as bad as a general nuclear conflagration. Very few humans survive, in the long run.”
Depends on the size. Barringer (Meteor Crater) was about 100M in diameter and would take out a county 100% and a state maybe 40%.
One the size of the recent Russian bolide would be a city-killer if it had come in at a steeper angle, but damage would be limited to a few miles.
So if you can be selective as to size and aim, it’s a weapon that is useful. A 5M rock at 31,000 mph would mess up Manhattan without much collateral. A 200 meter rock, even an ice core, would mess up most of the East Coast.
A 5 KM diameter impactor, like Chesapeake, would leave a 50 mile wide crater and would wipe half a continent, but it would be hard to steer here while retaining velocity.