WATCH: NASA Spots Brightest Lunar Explosion Ever Recorded

NASA scientists say they witnessed an extremely bright lunar explosion this past March. In fact, it is the biggest explosion they've seen since they started keeping track of such events in 2005.
"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," 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."

What's cool is if you had been looking at the moon at just the right time, you would have seen a one-second flash caused by the impact of a nearly-90 pound meteoroid that was traveling at 56,000 mph. The impact was picked up by one of the Meteoroid Environment Office's 14-inch telescopes.
One intriguing question is how a meteoroid can cause an explosion on the Moon, which has no oxygen atmosphere.
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."

Since NASA started keeping tabs of lunar strikes, it has counted more than 300 of them. They hope keeping track of these events will help them make decisions during long-term lunar missions.
"Is it safe to go on a moonwalk, or not?," NASA asks. "The middle of March might be a good time to stay inside."
We'll leave you with a graphic that shows all of the strikes the NASA program has recorded. The red square marks the spot of the March 17 impact:

NASA's lunar monitoring program has detected . The brightest, detected on March 17, 2013, in Mare Imbrium, is marked by the red square.

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Lunar Transient Phenomena 

 

 

January 23, 2007: If you stare at the Moon long enough, you start seeing things. "82 things to be exact," says Bill Cooke, leader of NASA's Meteoroid Environment Group. That's how many "transient phenomena" the group has video-taped since they started monitoring the night side of the Moon in Nov. 2005.
"In 107 hours of observing, we've tallied 20 lunar meteors + at least 60 Earth-orbiting satellites + one airplane + one terrestrial meteor = 82 in all."

Right: The NASA Meteoroid Environment Group's lunar observatory at the Marshall Space Flight Center in Huntsville, Alabama. Inset is one of two 14-inch telescopes simultaneously trained on the Moon during the group's observing sessions. [larger image]

This is the first systematic count of lunar night-side phenomena. "It gives astronomers an idea of what to expect when they undertake a lunar monitoring program from Earth."
Cooke's prime target is lunar meteors--flashes of light that occur when meteoroids hit the Moon's surface: video. "Of the 20 lunar meteors we've seen so far, about half come from well-known meteor showers such as the Leonids and Geminids. The other half are random meteoroids that take us completely by surprise." NASA is preparing to send astronauts back to the Moon and the agency is understandably interested in how often this happens.
"Everything else we've seen is just a coincidence, something flying in front of the Moon while we happen to be watching." Leading this category are Earth-orbiting satellites and pieces of space debris. This Orbcomm A4 communications satellite is a typical example:

Above: An Orbcomm communication satellite passes in front of the Moon on Nov. 17, 2006: video.

NORAD tracks more than 10,000 Earth-orbiting objects wider than 10 cm. "Some of them are bound to cross in front of the Moon while we're watching," he says. Objects like Orbcomm are easy to identify as satellites. Tumbling space debris, on the other hand, can be trickier: "A sudden glint of sunlight from a flat surface looks an awful lot like a lunar meteor flash," he explains. "So we have to be very careful. When we see a flash of light on the Moon, we always double-check that there was no piece of space junk passing by at that exact moment."
Back in days of Apollo, astronomers who monitored the Moon didn't have this problem. "There were very few satellites in Earth orbit, and a lunar transit was rare," he says. "But now we see one or two every night."
Here's a mystery: "Can you identify this object?" laughs Cooke. "Airplanes are my favorite."
So far, they have detected only one terrestrial meteor—that is, a meteoroid disintegrating in Earth's atmosphere: video. This may seem puzzling. During a typical meteor shower, novice sky watchers see dozens of shooting stars. Why has NASA counted only one? "The telescope's field of view is too narrow," explains Cooke. The human eye is much better for terrestrial meteor watching.
He's more interested in the Moon, anyway. Exploding meteoroids, tumbling satellites and jet airplanes: "It's a great show." What's next? "We plan to keep watching, so stay tuned."

Author: Dr. Tony Phillips | Editor: Dr. Tony Phillips | Credit: Science@NASA

NASA's Lunar Impact Monitoring Program
Videos:an Orbcomm A4 communication satellite, lunar airplane, lunar meteor, terrestrial meteor. Credit: The NASA Meteoroid Environment Group, MSFC.
Farside vs. Nightside: This article tells what was seen during a survey of the lunar night side. The night side shouldn't be confused with the farside. "We can never see the farside of the Moon," Cooke says. "But we often see the night side. It's any lunar terrain not lit up by the Sun, like the dark half of a quarter Moon."
The Vision for Space Exploration