Image showing the position of the craters detected by the Lunar Reconnaissance Orbiter. Bottom left is the older crater, lying within the Slater Crater, while above right is the younger, lying within the Faustini Crater. Albedo map credit: NASA GSFC/SwRI. Topographic map credit: NASA GSFC/ASU Jmoon
A team of scientists have discovered two young lunar craters in the Moon’s darkest southern regions, using a new technique involving ultraviolet light.
The craters are relatively young in geological terms: one is 16 million and the other is between 75 and 420 million years old.
The younger was found within the Faustini Crater and the older in the Slater Crater, both near the Moon’s South Pole.
They were discovered using the Lyman-Alpha Mapping Project (LAMO) instrument on the Lunar Reconnaissance Orbiter (LRO).
The device uses ultraviolet light to image areas of the Moon that are in permanent darkness, and can detect changes in reflectivity that help scientists estimate the craters’ ages.
When an impact occurs, material is ejected and forms a blanket of material surrounding the crater.
If the impact occurred relatively recently, the crater will have a rough surface and contain condensed, bright dust.
Older craters show more signs of weathering over the years and are covered with darker dust.
Using this method, the team from the Southwest Research Institute estimated one crater to be about 16 million years old, as it had a brighter surrounding area than the rest of the lunar landscape.
The second, older crater was less bright and its age was estimated as at least 75 million years old, but the fact that its ejected material was still visible meant it could not be any older than 420 million years.
Discoveries such as these help scientists piece together information about the history of Solar System formation.
Craters are caused by collisions, and collisions have played a large part in the evolution of the Solar System, including the formation of the Moon.
“These ‘young’ impact craters are a really exciting discovery,” says SwRI Senior Research Scientist Dr. Kathleen Mandt, who authored the paper.
“Finding geologically young craters and honing in on their age helps us understand the collision history in the solar system.
“Discovering these two craters and a new way to detect young craters in the most mysterious regions of the Moon is particularly exciting.
This method will be useful not only on the Moon, but also on other interesting bodies, including Mercury, the dwarf planet Ceres, and the asteroid Vesta.”