A 2,000-foot asteroid is expected to fly within 300,000 miles of Earth Saturday. That's pretty close.
Did you know smaller asteroids actually hit our planet 20 times a year? WGN's Larry Potash talked to an astronomer at the Adler Planetarium, who is watching space, to make sure asteroids don't kill us all.
Astronomer Mark Hammergren is an intergalactic hero, saving mankind from murderous space rocks. You can be a hero, too, and help Mark save the planet. Go to zooniverse.org, a website where you can chart asteroids, even with no training.