spacetoday.net: Curiosity provides evidence of loss of early Martian atmosphere

Posted: Tue, Jul 23, 2013, 6:53 AM ET (1053 GMT)
MSL self-portrait, November 2012 (NASA/JPL)

Data collected by NASA's Mars rover Curiosity have provided scientists with new evidence that Mars once had a thicker atmosphere that it lost relatively early in its history. A pair of papers published in the latest issue of the journal Science last week analyze ratios of carbon and oxygen isotopes in the carbon dioxide in the current Martian atmosphere. Heavier isotopes are present in the atmosphere in greater proportions than in the sun and elsewhere in the solar systems, suggesting that more lighter isotopes escaped. The results confirm previous studies that suggested the planet once had a thicker atmosphere, one that could support liquid water on the planet's surface, but that atmosphere was lost to space within the planet's first billion years.