Full title: Ancient bubbles in Australian rocks show early Earth's air weighed less than half today's atmosphere Air bubbles trapped in 2.7 billion-year-old Australian rock suggest the Earth's atmosphere weighed less than half of today and was much thinner than previously thought. Researchers analysed the size of air bubbles that formed at the top and bottom of lava flows along the Beasley River in Western Australia's Pilbara region almost three billion years ago and used the data to calculate the atmospheric pressure at the time. The results suggest that the air at the time exerted at most half the pressure...