Craters Young and Old
This image from NASA’s Lunar Reconnaissance Orbiter Camera (LROC) shows two similarly-sized craters in the Oceanus Procellarum (“Sea of Storms”) region of the Moon – a large mare on the Earth-facing side, on the northwestern edge. One crater is surrounded and covered by boulders and debris, denoting its young age compared to the smooth, degraded features of its older neighbor.
The younger crater on the right is approximately 1,300 feet (400 meters) across.
Although the Moon does not have weather to wear down its surface features like Earth does, it does get constantly bombarded by tiny particles of space debris, called micrometeorites. This steady rain serves to gradually soften the sharp edges of surface features like craters and ridges over the course of many hundreds of millions of years.
As it’s said on the LROC site at Arizona State University, “visit the crater on the right in about a billion or two years and you will see it looking similar to the degraded crater on the left.” Mark that on your calendar!
If you are very patient, visit the crater on the right in about a billion or two years and you will see it looking similar to the degraded crater on the left. Be careful though – when you show up the crater on the left may no longer be around!
Click here to explore a larger, zoomable view of the entire region imaged.
Credit: NASA/GSFC/Arizona State University