NASA’s Moon monitoring program says they have recorded the brightest explosion in the history of their program. They caught it on video and say that it could have been seen without the aid of a telescope.
“On May 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium,” says Bill Cooke of NASA’s Meteoroid Environment Office. “It exploded in a flash nearly 10 times as bright as anything we’ve ever seen before.”
They estimate that the boulder was about a foot wide, 40 kg in weight, and was traveling at about 56,000 mph when it hit. This would amount to an explosion as large as 5 tons of TNT.
On the evening of the meteor strike, NASA and University of Western Ontario cameras caught meteors in the earth’s atmosphere, leading them to believe that the Earth and Moon were both bombarded by meteorites at the same time. Lucky for us, the Earth has an atmosphere to protect it, and most meteorites burn up before they strike the ground. The Moon does not have an atmosphere, so even small meteorites can strike with great force, causing large explosions like this one.
NASA says they will keep an eye on meteor storms like this. In future manned Moon missions it will be important to know when it might be dangerous for astronauts to be out and about on the lunar surface.
“We’ll be keeping an eye out for signs of a repeat performance next year when the Earth-Moon system passes through the same region of space,” says Cooke. “Meanwhile, our analysis of the May 17th event continues.”