The 10,000 ton asteroid that exploded above the Russian city of Chelyabinsk in February produced such a powerful shockwave that it raced around the world twice, according to a new study published in the journal Geophysical Research Letters.
Researchers report that 20 world-wide monitoring stations, designed to detect ultra-low frequency sound waves emanating from nuclear-test explosions, managed to record the waves produced by the asteroid’s explosion for the first time ever.
The Russian meteor hit the atmosphere at 11.6 miles (18.6 kilometers) per second. The concussive blast was heard at monitoring stations as far away as Greenland and Antarctica.
Traveling at hypersonic speeds, near Mach 60, the meteor experienced increasing air pressure as it pierced the denser part of Earth’s atmosphere, finally imploding 14 miles (23 kilometers) above the Earth. Hundreds of fragments rained down, with the largest pieces weighing up to half a ton. (See pictures of the damage it caused.)
The research team also confirmed that the blast from this 56-feet-wide (17-meter-wide) space rock had an estimated force of 460 kilotons of TNT—equivalent to about 30 atomic bombs dropped on Hiroshima during World War II.
The February 2013 event now ranks as the second largest impact on Earth since the Tunguska fireball in 1908. The 1908 event released nearly ten megatons of TNT and scorched millions of trees over hundreds of square miles. (Related: “Russian Meteorite Spotlights History’s Other Crashes.”)
The last comparable meteoroid atmospheric detonation occurred above the skies of Sulawesi, Indonesia, back in 2009 and was measured at 50 kilotons.
Scientists estimate a Chelyabinsk-like airburst occurs about once a century, while a much bigger Tunguska-like event, thankfully, may only come around once every few centuries. (Related: “Russian Meteor a Surprise—But Many More Out There.”)