Achievement

Research from our IGERT Astrobiology program was featured on a cover story for Nature magazine of 19 April 2012 (Vol. 484, pp. 359-62; commentary on pp. 322-4). Lead author was former IGERT Associate Sanjoy Som (now a postdoc at NASA Ames Research Center), along with Professors Roger Buick and David Catling of the Earth & Space Sciences Dept.; the research was part of Som’s thesis work in our Program. Som et al. made detailed measurements of the sizes of impressions made by raindrops in 2.7-billion-year-old rocks from South Africa. They concluded that the Earth’s atmosphere 2.7 billion years ago was no more dense than twice the present value, and probably even less. This result argues against the early Earth having a strong greenhouse effect, which has been invoked as a possible cause of the early Earth not being frozen despite the fact that the Sun was 20% dimmer at that time (the “Faint Young Sun Paradox”).