Chelyabinsk-sized rocks may come to Earth every 30 years, on average
Courtesy of Science/AAAS
Meteor impacts such as February’s explosion over Chelyabinsk, Russia, the most powerful observed in a century, may occur more frequently than thought. An analysis of recorded impacts over the past two decades suggests that Chelyabinsk-sized objects strike the planet every few decades, on average, rather than once every century or two.
“There were inklings of this before, but this is the strongest statement that’s been made,” says Paul Chodas, a planetary scientist with NASA’s Near Earth Object Program at the Jet Propulsion Laboratory in Pasadena, Calif., who was not involved in the research. If confirmed, scientists will need to reassess the risk of impacts and come up with new strategies for spotting space rocks tens of meters in diameter, which can cause widespread damage and injuries.
It’s impossible to find and track each of the millions of objects that cross Earth’s path. Instead, astronomers maintain a census of objects