The researchers investigated the consequences of impact basin formation on the two lunar hemispheres. Here, they are using conditions representative of the nearside hemisphere. This simulation shows the first two hours after an impact into the Procellarum KREEP Terrain onthe Moon, made by a 30-km asteroid impacting at 10 km/s ~4 billion years ago. This video relates to a paper that appeared in the 8 Nov., 2013, issue of Science, published by AAAS. The paper, by Katarina Miljković at Institut de Physique du Globe de Paris in Paris, France, and colleagues was titled, "Asymmetric Distribution of Lunar Impact Basins Caused by Variations in Target Properties."