Moon explosion: NASA Reveals Bright explosion on the moon visible from Earth. A meteoroid struck the surface of the moon recently, causing an explosion that was visible on Earth without the aid of a telescope, NASA reported Friday. But don't be alarmed if you didn't see it; it only lasted about a second. "It exploded in a flash nearly 10 times as bright as anything we've ever seen before," said Bill Cooke, of NASA's Meteoroid Environment Office. NASA astronomers have been monitoring the moon for the past eight years, looking for explosions caused by meteoroids hitting the lunar surface. It's part of a program to find new fields of space debris that could hit Earth. NASA says it sees hundreds of detectable lunar meteoroid impacts a year. None however can match the size of the explosion they say they saw March 17. NASA says the meteoroid was about 40 kilograms and less than a meter wide, and it hit the moon's surface at 56,000 mph. It glowed lik