NASA spots enormous meteor explosion only 16 miles from Earth's surface
The huge fireball was detected by a US military satellite and then referred to the space agency for investigation.
Monday 18 March 2019 10:01, UK
A meteor was the cause of an enormous explosion in the atmosphere last year, NASA has announced.
The blast was 10 times more powerful than the atomic bomb dropped on Hiroshima.
It was the second-largest such explosion in the last century, just behind the meteor which exploded over the Russian region of Chelyabinsk in 2013.
The most recent meteor exploded over the Bering Sea, also near Russia.
It was just 25.6km (16 miles) above the planet's surface and hurtling down at a steep angle of seven degrees when the friction of the atmosphere caused it to explode.
The explosion was detected by US military satellites last year, and subsequently referred to NASA.
According to NASA's planetary defence officer Lindley Johnson, the fireball exploded near to a common flight route, and so researchers are asking airlines if they saw any signs of it.
The explosion from the Bering Sea meteor from December 2018 was only 40% as powerful as the Chelyabinsk meteor strike in 2013, which injured hundreds of people when it exploded.
It briefly outshone the sun and inflicted severe burns on observers below, as well as smashing windows and rattling buildings.
But researchers say a more solid rock would have caused greater damage and casualties.
The Chelyabinsk meteor was at its brightest and hottest when it was 18 miles above the Earth. Its speed at this point has been calculated at 40,000mph, or 11.6 miles per second.
That means a rock that was initially the size of a double-decker bus was travelling at 20 times the speed of a bullet.
It was the largest object to hit Earth since the Tunguska event of 1908, when an exploding comet or asteroid destroyed 2,000 square kilometres of Siberian forest.