Every year, dozens of asteroids come closer to our planet than the moon is, and yet catastrophic collisions are exceedingly rare. Now, a new study proposes that Earth has a built-in defense system — its intense gravitational forces — that it uses to tackle asteroid interlopers.
The enormous masses of planets and their moons mean they exert tremendous gravitational forces on nearby objects. The differences in gravity these objects experience, called tidal forces because astronomers used them to explain how the moon causes tides on Earth, can be so strong in some cases that the objects get ripped up ― a process called tidal disruption.
