NASA's lunar monitoring program has detected hundreds of meteoroid impacts. The brightest, detected on March 17, 2013, in Mare Imbrium, is marked by the red square. Credit: Science@NASA

NASA researchers have reported the biggest explosion on the lunar surface in the 8 year history of a Moon-monitoring program.

The object was about the size of a small boulder and struck in the Moon’s Mare Imbrium, creating a flash nearly 10 times as bright as anything specialists had recorded before.

The impact took place on March 17 with the meteoroid slamming into the Moon at 56,000 mph. The resulting explosion packed as much punch as 5 tons of TNT.

According to Bill Cooke of NASA’s Meteoroid Environment Office at the Marshall Space Flight Center, anyone looking at the Moon at the moment of impact could have seen the explosion…no telescope required.

Indeed, for about one second, the impact site was glowing like a 4th magnitude star. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.

Controllers of NASA’s Lunar Reconnaissance Orbiter have been notified of the strike. The crater could be as wide as 20 meters, which would make it an easy target for LRO the next time that Moon orbiting spacecraft passes over the impact site.

“Opportunities will appear later in the summer,” Mark Robinson at Arizona State University told this Coalition reporter. He runs the sharp-eyed camera system on LRO. “Hope we find it!”

Lunar meteors

Ron Suggs, an analyst at the Marshall Space Flight Center, was the first to notice the impact in a digital video recorded by one of the monitoring program’s 14-inch telescopes. “It jumped right out at me, it was so bright,” he recalls.

Cooke believes the lunar impact might have been part of a much larger event that night, as NASA and University of Western Ontario all-sky cameras picked up an unusual number of deep-penetrating meteors right here on Earth.

“These fireballs were traveling along nearly identical orbits between Earth and the asteroid belt,” Cooke says. This means Earth and the Moon were pelted by meteoroids at about the same time.

“Lunar meteors” crash into the ground with fair frequency. Since the monitoring program began in 2005, NASA’s lunar impact team has detected more than 300 strikes, most of them orders of magnitude fainter than the March 17th event.

For a special video report on this event, go to:

http://www.youtube.com/watch?v=IYloGuUZCFM

By Leonard David via Tony Phillips/Science@NASA