Sedimentary rock is comprised of sediment, as the name suggests. Over time, tiny minerals, sand, rocks, and debris layer on ...

China's Yutu 2 rover spotted an elongated 'milestone' rock sticking out from the surface on the far side of the moon. Experts say it formed after meteor impacts blew rocks away from the ground.

As the rock formations warm up, cracks and pockets opened up, releasing methane that had been trapped inside. The concentrations of methane were elevated by about 5 percent, Froitzheim said.