US detects huge meteor explosion
At about noon local time on 18 December, the asteroid barrelled through the atmosphere at a speed of 32km/s, on a steep trajectory of seven degrees. Measuring several metres in size, the space rock exploded 25.6km above the Earth’s surface, with an impact energy of 173 kilotons 10 times the energy released by the Hiroshima atomic bomb.
The blast was the second largest of its kind in 30 years, and the biggest since the fireball over Chelyabinsk in Russia six years ago. It was 40% the energy release of Chelyabinsk, but it was over the Bering Sea so it didn’t have the same type of effect or show up in the news.
A fireball this big is only expected about two or three times every 100 years.