The explosion from an asteroid over Russia was 30 times the force of the Hiroshima nuclear bomb, new studies have concluded.
They also revealed the chance of a repeat strike was maybe ten times greater than previously thought – leading to calls for early warning systems to be installed.
The explosion over Chelzabinsk in February injured more than 1,200 people.
The mass of the asteriod was as much as 13,000 metric tonnes – according to studies published in Nature and Science – , which is double what was initially thought.
The asteroid roared through Earth’s upper atmosphere at an initial speed of around 19 kilometres per second — more than 50 times the speed of sound.
It shone 30 times brighter than the sun and had an energy equivalent to more than 500 kilotons of TNT, 30 times the force of Hiroshima.
Professor Peter Brown, from the University of Western Ontario, Canada, lead author of one of the studies, told the BBC: “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.
“In the case of Chelyabinsk, a few days’ to a week’s warning would have been valuable.”“We were able to capture the occurrence rate you would expect of things like Chelyabinsk and smaller impacts. When you compare that to the numbers you get from telescopic [observations], our numbers are several times higher.
“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.”
“Chelyabinsk was an eye-opener, but we shouldn’t give it an excessive amount of importance as to what may come in the future,” said Bill Cooke, head of NASA’s Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama.
“A lot is going to depend on where an event occurs. The odds are an event will occur over the ocean rather than over a populated area.”