But what about a rock on a direct path toward Earth? How would we stop it? Scientists say a nuclear bomb might be the best bet.
A year ago, scientists were taken by surprise when a small asteroid exploded over Russia, sending out shock waves that shattered windows and injured some 1,500 people.
It was a wakeup call, they say, a reminder of the damages an asteroid could wreak. "A couple of years ago, I had to use the dinosaur example to justify our research," Bong Wie, director of the Asteroid Research Deflection Center (ADRC) at Iowa State University, told Space.com. "Now, that's no more -- we had this major event."
Wie and his colleagues are working on developing a Hypervelocity Asteroid Intercept Vehicle (HAIV), a rocket-like vehicle that could deliver a nuclear bomb to an asteroid propelling toward Earth.
"We have the solution, using our baseline concept, to be able to mitigate the asteroid-impact threat, with any range of warning," Wie told attendees at a NASA Innovative Advanced Concepts meeting at Stanford University earlier this month.
Wie's team say they've conducted computer models to prove that -- with a roughly 30-day warning -- they could halt an asteroid as wide as 1,000 feet. A smaller meteor shower could result from the exploding debris -- one similar to the incident in Russia -- but nothing compared to what Earth would suffer in the even of a direct hit.
Wie says once his team develops its HAIV, it could be coupled with an asteroid tracking system to protect Earth.
The University of Hawaii has already developed a tracking systems called the Asteroid Terrestial-impact Last Alert System, or ATLAS. The system can predict the collision of 26-foot asteroids 24 hours in advance, 148-foot asteroids a week ahead of time, and 459-foot asteroids three weeks before expected impact.