NASA scientists have been monitoring meteoroid impacts on the Moon for the last 8 years now. Meteors hitting the surface of the moon are a very normal phenomenon, since there is a lack of atmosphere, there is no resistance to the rocks falling from space. When a meteor hits the surface of the moon, its observed as a flash by the scientists here on earth.
Check out the Sciencecast (science@nasa) video
On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium. It exploded in a flash nearly 10 times as bright as anything we’ve ever seen before.
Anyone looking at the moon at the time of impact could have seen the explosion with the naked eye!
The meteoroid was 40 kgs, measuring 0.3 to 0.4 meters wide, and hit the moon while travelling at 56,000 miles per hour! The resulting explosion packed as much punch at 5 tons of TNT.
So, why do we see a bright flash on the moon?
Unlike earth that has an atmosphere, the moon doesn’t have one, to protect the surface from incoming meteors. When something travels as fast as a meteor in an atmosphere, the friction generates enough heat to cause the meteor to dissipate in the atmosphere itself.
You may be wondering, how come there is an explosion on Moon if there is no oxygen to cause the flame to burn in the first place?
Well, the Lunar meteors don’t require oxygen or combustion to make them visible. They hit the surface with so much kinetic energy, that the heat is enough to melt the rock. The light is the thermal glow of the molten rock and hot vapors rather than combustion.
If humans make a base on the moon
If humans ever decide to go and make a base on the moon, this is probably going to be one of our biggest concerns, apart from the fact that there is no atmosphere on the Moon. Our structures would have to be - either strong enough to withstand these kinds of explosions, which is very unlikely. Or, we must have a way to relocate bases at short intervals. There would have to be an early warning system for incoming meteors, of some sort. One way to overcome these problems would be to make an underground base on moon.