What Happened To Mars’ Atmosphere? Flagstaff Scientist Says It Didn’t End Up In Rocks

Sep 9, 2015

A new study co-authored by a Flagstaff researcher deepens the mystery of what happened to Mars’ ancient atmosphere.

The Nil Fossae plains region contains the largest known carbonate-rich deposit on Mars. This color-coded composition was created from two instruments on board NASA’s Mars Reconnaissance Orbiter.
Credit NASA/JPL-Caltech/JHUAPL/Univ. of Arizona

Christopher Edwards of the U.S. Geological Survey is the lead author of the study. He examined the idea that Mars once had a thick atmosphere of carbon dioxide that eventually ended up buried, or “sequestered,” underground. His research shows that hypothesis is unlikely.

Edwards used data from three orbiting spacecraft to measure the size of Mars’ largest deposit of carbon-bearing rock. He found it didn’t contain enough carbon to support the sequestration idea.

Edwards says that might mean ancient Mars didn’t have a thick atmosphere after all. Another possibility is that Mars lost most of its atmosphere to space, blown off by solar wind. That’s one of the questions that NASA’s latest Mars orbiter, MAVEN, may answer.