A meteor strike like the one in Chelyabinsk, Russia, earlier this year might seem like a once in a lifetime event, but a new study in Nature says that isn't the case. Using data from sensors around the world, researchers found that big asteroids have hit Earth's atmosphere with "surprising frequency," the BBC reports—it's just that most explode over oceans or remote areas. "Something like Chelyabinsk, you would only expect every 150 years on the basis of the telescopic information. But when you look at our data and extrapolate from that, we see that these things seem to be happening every 30 years or so," says the lead author. The frequency of such hits might be up to seven times greater than previously thought, reports AP.
Ideally, scientists would have had a few days or weeks' notice of the strike, which is why "having some sort of system that scans the sky almost continuously and looks for these objects just before they hit the Earth, that probably is something worth doing." says the researcher. Meanwhile, a separate study in Nature has found the source of Russia's meteor strike. Researchers think the rock that hit Chelyabinsk broke off from a mile-wide asteroid known as 86039—resulting in an impact that created 30 times the explosive power of the Hiroshima bomb, the Independent reports. "If humanity does not want to go the way of the dinosaurs, we need to study an event like this in detail," says one professor.