(USATODAY.com) - A boulder-sized meteor that slammed into the moon in March caused the biggest lunar explosion ever observed by NASA.
The strike, which packed as much punch as five tons of TNT, was so bright that anyone looking up at the moon at that moment could have spotted it -- no telescope required.
"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," said Bill Cooke, from NASA's Meteoroid Environment Office, in a statement on Friday. "It exploded in a flash nearly 10 times as bright as anything we've ever seen before."
NASA has been monitoring the moon for signs of explosions caused by meteoroids for the past eight years, detecting more than 300 strikes since the program began. One of the program's goals is to identify new streams of space debris that pose a potential threat to the Earth-Moon system.
A NASA satellite orbiting the moon is on the hunt for the newly formed crater, which scientists estimate could be as wide as 66 feet.