Cosmic rays alter chemistry of lunar ice, may create building blocks of lifeSpace scientists report they have quantified levels of radiation on the moon's surface from galactic cosmic ray (GCR) bombardment that over time causes chemical changes in water ice and can create complex carbon chains similar to those that help form the foundations of biological structures. In addition, the radiation process causes the lunar soil, or regolith, to darken over time, which is important in understanding the geologic history of the moon.
Source: Cosmic rays alter chemistry of lunar ice, may create building blocks of life (http://www.sciencedaily.com/releases/2012/03/120319135245.htm)