In the past two and a half years, the Moon has taken a real beating. NASA astronomers have observed over a hundred explosions on the Moon during this time, caused by meteoroids both large and small, slamming into the Moon at speeds of up to 160,000 miles per hour (257,495 kilometers per hour).
The Moon gets pelted constantly â€“ over a metric ton of material falls on the Moon every day! Most impacts are too dim to see with the naked eye because they are small micrometeorites. The rate of the flashes from larger impacts increases dramatically â€“ up to an impact every hour â€“ during meteor showers such as the Perseids and Quadrantids. The sporadic impacts account for twice as many observable events as compared to meteor shower impacts.
If you were standing on the Moon, you wouldn’t see these impacts as “shooting stars,” though, since there is no atmosphere in which they can burn up. The explosion is also not something like one would see here on Earth, as the absence of oxygen doesn’t allow for any combustion. The kinetic energy of the impact heats up the rocks on the surface to the point where they become molten, and glow for a short period after the impact.
Pictured left is the flash from a confirmed impact on March 13th, 2008, as captured by amateur astronomer George Varros. The small white point in the bottom right of the picture is where the impact occurred. He has an animation of the event on his site.
Monitoring the number of impacts on the Moon is important for future missions to visit our smaller neighbor, as well as for the eventual establishment of a Moon base. It will be important to know when astronauts should take cover from potential strikes during peak periods of impacts. After all, even a small meteoroid traveling between 4500 mph (7,242 kph) and 160,000 mph (257, 495) could do a lot of damage to a space suit or lunar base. A typical blast that can be seen with a backyard telescope from Earth is equivalent to a few hundred pounds of TNT. I know I wouldn’t want to go for a Moon walk during a meteor shower…
NASA has been observing lunar impacts with one 14-inch (36 cm) telescope and one 20-inch (51 cm) located at the Marshall Space Flight Center in Alabama, and one 14-inch telescope located in Georgia.
But it’s not just NASA that can see these lunar fireworks: NASA’s Meteoroid Environment Office has called for amateur astronomers to help in recording and confirming these flashes. If you have a lot of patience, a telescope and a way to record the flashes, check out their site to get started.