The Moon is much more often by meteorite hit than before expected. Scientists have evaluated before and after images and found more than 200 fresh impact craters with a diameter between 3 and 43 meters. These are important information for future colonization of the moon.
So it looks like the footprints which have so far left astronauts on the Moon, will disappear faster than expected. American scientists have found 222 fresh impact craters that cause that the loose surface rocks of the Moon is churned out one hundred times faster and renewed as it has been so far.
“With this circulation rate of the Apollo will be gone the footprints astronauts in some ten thousand years ago and not only millions of years”, says Mark Robinson of Arizona State University in Tempe.
High resolution photos before and after meteor strikes on the lunar surface
Well, it was Mark Robinson and the team of scientists led by Emerson J. Speyer in their study, which was published in the weekly journal nature, not the footprints of the astronauts. Rather, they wanted to find out what the current rate of Lunar meteorites on the Moon is actually and what effect this has on the circulation of the regoliths of loose rock surface. For this, the team has evaluated 14.092 image pairs, Lunar Orbiter (LRO), reconnaissance from the NASA space probe. It’s before after pictures showing same snippet of the lunar surface in the space of several months. Since 2009, the orbiter circling the Moon, and provides high-resolution pictures of its surface.
When evaluating the recordings, the scientists discovered over 200 new craters with a diameter between 3 and 43 m. These are about 30% more than the previously common models, expect. The image analysis revealed further, sometimes unexpected, results. “Before the Lunar Orbiter to the Moon sent reconnaissance, it was generally assumed, that it would take a few million years for the meteorites had circulated the top two centimeters of the surface of the rock”, says Emerson Speyerer. “The new pictures show much faster that changed the surface.”
Entire surface of the Moon is circulated in 81,000 years once
In addition to the larger impact craters, scientists discovered also over 47,000 small changes in the regolith. You suspect that the top layer was churned by secondary impacts from rocks, which was in turn been pushed out by the primary impact. In their calculations, the team came to the surprising conclusion that almost the entire surface (99%) will be transferred to 81,000 years once to the frequency of these changes with its depth in the regolith. That is more than 100 times faster than assumed in earlier models calculated only the primary impacts.
“These much higher circulation rate of the surface rock will be important information for designers of future lunar bases,” Speyer says. “Building on the Moon must be designed to withstand impacts from small particles, which are traveling at a speed of up to 500 meters per second”. A concrete danger for a moon base would be less the direct impact of a meteorite, but intense smaller impacts by rock whirled-up.