New research counters the assumption that Earth’s ancient atmosphere billion of years ago was thick to level out weak sunlight. But scientists from the University of Washington studied trapped bubbles inside old geological formations and discovered evidence that Earth’s atmosphere was thinner than Mount Everest’s is today, according to a Tech Times report.
Researchers also investigated remnants of gases and how the interplay of the shifting ancient climate and young biology affected our planet’s development. Roger Buick, University of Washington and space sciences professor and co-author of the study, said that trapped bubbles in cooling lava were used to measure the time-worn lava elevation. What’s known as a paleobarometer was used to record the weight of ancient air.
But the scientific team needed to source a location where ancient lava formed at sea level. Tim Blake from the University of Western Australia and co-author led them to the Beasley River hosting 2.7 billion-year-old basalt lava.
As lava settles from the top to bottom, trapped bubbles residing at the bottom become noticeably smaller than those at the top. The size variations relate to varying degrees of air pressure exerted on the lava’s layers as it cools. Researchers bore through geological layers to record the bubbles’ differing sizes.
On-site samples indicated that the primordial atmosphere was quite lightweight and later supported by more detailed x-ray scans from various lava flows. Specifically, the bubbles showed that pressure was half of what Earth’s is today. “We’re still coming to grips with the magnitude of this,” said Buick, and “It’s going to take us a while to digest all the possible consequences.”
The study’s results implicate the ancient climate in many ways. Previously, researchers verified the presence of liquid water meaning that the old atmosphere was comprised of many greenhouse gases like carbon dioxide and methane and only traces of nitrogen. Blue Marble Space CEO and lead author Sanjoy Som, said, “We are 95 percent sure that the pressure was between 0 and 0.5 atmospheres.” These measures correspond to Mount Everest’s elevation of 5,500 meters (3.4 miles).
Various samples of stromatolite suggest that single-celled microbes thrived in the harsh thin atmosphere when the sun had less penetration.