Manicouagan Crater in Québec, Canada

An impactful day

We'll be the ones to drop the news on you: It's Asteroid Day! Today you're invited to explore a realm of science usually encountered only through white-knuckle action flicks: asteroid impact avoidance, or the study of what the heck we do if we spot a big chunk of space junk hurtling right at Earth. That's right, don't worry: People somewhere are coming up with plans for this.

Good thing, because as our photo shows, asteroid impacts do happen. Manicouagan Crater, aka the 'eye of Québec,' was formed by a 3-mile-wide meteorite that hit Earth about 215 million years ago. Much more recently, an explosive meteorite leveled 800 square miles of Siberian forest in what's called the Tunguska event. It was 113 years ago today, and Asteroid Day's date was chosen in recognition.

So if you find yourself casting paranoid glances at the sky today, maybe do a little searching on how scientists are learning to prevent potential impacts. Proposed plans involve everything from altering an asteroid's course via a gravitational field, to delaying its approach by attaching rocket thrusters, to good old-fashioned blowing it up. Yay science!