Since 2005, a team at NASA has been monitoring meteoroid explosions on the surface of the moon. In March, they announced yesterday, they observed an explosion so bright it would have been visible from Earth without a telescope. "For about one second," NASA said in a statement, "the impact site was glowing like a 4th magnitude star." It was nearly ten times as bright as any other previously recorded impact.
Unlike our safely cocooned planet, the moon has no atmosphere to protect it, and meteoroids do not burn up as they approach the surface. Over the past eight years, NASA scientists have observed more than 300 impacts, some of which are mapped below, with the March strike denoted by the red square.
What does it mean for something to "explode" in an environment with no oxygen? What are you actually seeing in the video above? NASA explains:
Lunar meteors don't require oxygen or combustion to make themselves visible. They hit the ground with so much kinetic energy that even a pebble can make a crater several feet wide. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.
In the case of this major explosion -- which occurred on March 17th, during a period of increased meteor activity in Earth's atmosphere as well -- the rock struck the lunar surface at a speed of 56,000 miles per hour. The next time NASA's Lunar Reconnaissance Orbiter is in the vicinity, it will have its sights set on the Mare Imbrium region where the explosion occurred, searching for a new crater that could be as many as 20 meters wide.