Solar System Exploration Division (690) Featured Image
Ejecta Starburst
Small, Copernican-aged craters abound on the Moon and their ejecta blankets often look like miniature starbursts. For young craters like this one, located on the far side at 25.876°S, 136.081°E, the ejecta is high-reflectance because it was recently exposed by the impact process and is thus really fresh material.
When we observe the ejecta blanket in detail, there are variations in reflectance within the ejecta and it looks as though the ejecta swept out from the crater in sheets. During the impact event, material is ejected from the growing crater and is emplaced over a short period of time. However, the emplacement is not instantaneous and the ejecta is expelled from the growing crater at different speeds and angles depending on where within the impact cavity it originates. Some of the target rock is melted and is also sprayed out of the crater with the pulverized target material. The bright and dark fingers of ejecta seen in the image may represent granular and melt materials, respectively. Furthermore, the ejecta farthest away from the crater is thinner and less continuous than the ejecta closest to the crater.
Image Source: http://lroc.sese.asu.edu/news/index.php?/archives/529-Ejecta-Starburst.html
