50,000 years ago a bit of wayward rock about 50m across met Earth and left this 1200m wide crater in Arizona.
Ponder the momentum of 50m bit of rock that left a hole over a kilometer wide and 200m deep.
If one was coming. Would we know?
Thanks to NASA and The Earth Observatory
UPDATE: JoeV in comments adds an interesting link to Tracking space junk at Satview.org. An old satellite is coming in right now. It’s over Alaska (moving fast) at 153km high and falling quickly. Cosmos 1220, a Soviet era military surveillance satellite. Eddie adds a different link which suggests Cosmos is expected to crash into the Pacific in hours. Amazing what you can find out on the Internet.