Fossil Raindrops: Reveal Early Atmosphere
One of the biggest unknown element of the environment of the ancient Earth, billions of years ago when life was first finding a foothold, is just how thick the atmosphere was. Geochemists can get some idea of the composition of different gases in the air at the time, but there’s no way of judging what the atmospheric pressure was. And this is crucial for understanding how much insulation our young planet received.
But now, David Catling at the University of Washington in Seattle has come up with an intriguing way for measuring the thickness of Earth’s primordial atmosphere: study the ancient raindrop impressions formed in some sediments before they turned to stone.