While the evidence for liquid water on early Mars is well established, researchers have been hard-pressed to explain how this might have happened, considering the sun was much fainter in the past than it is today. New research by alumnus Ty Robinson and several VPL collaborators now shows that in addition to carbon dioxide and water vapor, Mars’s ancient atmosphere could have also contained just enough hydrogen to create a strong greenhouse effect, raising temperatures enough to allow for liquid water on the planet’s surface. Read the UW News release here.