May 17, 2013: For the past 8 years, NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface. "Lunar meteor showers" have turned out to be more common than anyone expected, with hundreds of detectable impacts occurring every year.

A boulder-sized meteor slammed into the moon in March, causing an explosion so bright anyone looking up at the right moment would have spotted it, NASA said. NASA’s Meteoroid Environment Office is reporting the discovery of the brightest impact seen on the Moon in the eight years the monitoring program has run the National Geographic reports. About 300 lunar impacts have been logged over the years but this latest impact, from March 17, is considered much, much brighter than anything else observed. It is understood the space rock left a 20m-wide crater after it slammed into the Moon's surface at 90,000km/h.

“We have seen a couple of others in the ‘wow’ category but not this bright,” said Robert Suggs, manager of NASA’s Lunar Impact Monitoring Program at Marshall Spaceflight Center in Huntsville, Alabama. The blast lasted only about a single second and shone like a 4th magnitude star—making it bright enough to see with just the unaided eye.

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