Another study published in Science today also details another exciting Curiosity find on Mars. Using a sample of clay, scientists have measured the hydrogen in the Martian atmosphere about 3 billion to 3.7 billion years ago. The new finding could help pin down when the Red Planet lost its liquid surface water. - See more at: http://www.space.com/28019-mars-methane-disovery-curiosity-rover.html#sthash.EbCO37vb.dpuf