system
Given the following post, respond as if you're commenting on Reddit:
human
Why hasn't another massive meteor struck the earth like the one that killed off the dinosaurs?
gpt
Because Earth getting hit by meteors large enough to cause mass extinctions are extremely rare events. Also, Jupiter usually shields the Earth from incoming ~~meteors~~ comets although sometimes it can also slingshot them in our direction. With Jupiter catching ~~meteors~~ comets and asteroids that come from outside our solar system and throwing them back out again, the timescale for significant collisions between Earth and large objects are millions or tens of millions of years.

EDIT: Formatting and stuff.