[math-fun] ancient earth allegedly had thin atmosphere

Sanjoy M. Som, Roger Buick, James W. Hagadorn, Tim S. Blake, John M. Perreault, Jelte P. Harnmeijer & David C. Catling: Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels, Nature Geoscience March 2016 http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2713.html claims air bubbles in lava show the Earth's atmosphere at sea level 2.7 Gyr ago, was roughly comparable in pressure to today's top of Mt.Everest. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)