March 17, 2013 Lunar Impact Forms a New Crater

After simulating the distant view of a new impact, the camera zooms up to the surface to show actual before/after images of a new 12-meter crater taken by the Lunar Reconnaissance Orbiter narrow-angle camera. (The impact that formed this crater wasn't seen from Earth, but a different one was.) No, not that kind of gardening. In this case, gardening refers to the mixing and disturbance of the top layers of lunar regolith that happens when impacts form new craters. The material excavated from the crater site is sprayed in all directions, creating secondary craters and splats of lighter and darker dust on the surface.The narrow-angle camera (LROC NAC) aboard Lunar Reconnaissance Orbiter (LRO) has photographed a large percentage of the Moon's surface multiple times. By looking for differences between earlier and later images, the LROC team has found over 200 new craters large enough for the camera to see (at least 5 meters in diameter), as well as thousands of what they call splotches, many of which are likely caused by smaller craters.In a paper in the October 13, 2016 Nature, Emerson Speyerer and his coauthors divide the crater ejecta into four zones that differ in brightness and distance from the crater, and they explain the processes involved in the formation of each zone. They also use the number of craters and splotches to infer the gardening rate, the rate at which the top few centimeters of regolith is churned and replaced by impacts. Their conclusion is that this is happening over 100 times faster than previously thought.The visualization simulates the formation of one of the craters featured in the paper. We first see a flash, then zoom all the way to the surface, where the animation blinks between the actual before and after LROC NAC images (M1105837846R and M1121160416R) that were used to detect this new 12-meter crater. Finally, we see the ratio of the two images, which very clearly shows both the new crater and the radial pattern of ejecta. Related pages

Explore how a NASA orbiter searches for new craters on the moon. Learn about the techniques scientists use to investigate the formation of new lunar impact craters in this video. LRO takes high-resolution images of the moon’s surface that scientists can zoom into and pinpoint the location of new craters. Before and after images taken by LRO show the location of a new 60-foot in diameter crater (right) that formed on March 17, 2013. The March 17 crash flung material nearly 100,000 feet from the impact site (red circle). Yellow lines and circles above show the debris pattern. For More InformationSee [NASA.gov](http://www.nasa.gov/content/goddard/nasas-lro-spacecraft-finds-march-17-2013-impact-crater-and-more) Related pages

The Lunar Reconnaissance Orbiter's powerful cameras are enabling scientists to find present-day impact craters on the Moon.Watch this video on the NASAexplorer YouTube channel.For complete transcript, click here. VISUALIZATION - Artist's concept of the bright lunar impact in Mare Imbrium on March 17, 2013. VIDEO RECORDING - Bright flash in Mare Imbrium on March 17, 2013. Video captured by NASA's Marshall Space Flight Center. IMAGE - Close up of the March 17 impact crater. Available in before and after versions. IMAGE - Close up of the March 17 crater with image processing. The outline indicates soil ejected during impact. IMAGE - LROC mosaic showing the location of the March 17 crater and the pattern of ejected material. Available in labeled and clean versions. VISUALIZATION - Map of present-day lunar impact craters Planetary scientists believe that small impacts regularly bombard the Moon, but until recently, they’ve had no way to distinguish new craters from the already pockmarked lunar surface. In 2009, NASA’s Lunar Reconnaissance Orbiter (LRO) arrived at the Moon and began taking high-resolution photographs. By comparing pictures taken early in the mission with more recent images, the LRO camera team has discovered more than two-dozen new impact craters – including an 18-meter-wide crater caused by a bright flash on March 17, 2013.Learn more about this finding. For More InformationSee [http://lroc.sese.asu.edu/posts/770](http://lroc.sese.asu.edu/posts/770) Related pages