NASA witnessed the biggest and the brightest explosion in the history of the moon caused by a meteor that crashed into it. The explosion was briefly visible to the naked eye, March 17, 2013.

A meteor crashed into the moon and created the biggest explosion in its history March 17, practically creating a new hole on its surface. NASA scientists describe this event as a landmark in moon's history since they started watching it for signs of "Lunar meteor showers" 8 years ago.

"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," said 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."

The explosion was visible to the naked eye for a brief second only. But the intensity of the massive explosion was like a "4th magnitude star," as described by the NASA officials. The historical event was not witnessed real time by any NASA officials until an analyst at the Marshall Space Flight Center, Ron Suggs, viewed a recorded video from one of his monitoring program's 14-inch telescopes.

"It jumped right out at me, it was so bright," he recalls.

The meteoroid impact was strong enough to leave a 20-meter crater on the surface of the moon. According to NASA's report, the meteoroid weighed 40kg and was 0.3 to 0.4 meters wide. The impact was powerful because of the speed of the meteoroid. The recorded speed of the meteoroid was 56,000mph. Such an explosion can be equivalent to setting off 5 tons of TNT.

NASA started the monitoring program to record lunar meteor showers in 2005. Since then, NASA officials have recorded more than 300 strikes but none were worth noting as the one which occurred March 17. The  NASA lunar impact team will be analyzing this event in detail and will also look out for any sign of recurrence when the Earth and Moon will pass through the same region of space next year.