Tiny bubbles that formed inside volcanic rock 2.7 billion years ago are providing big insights into the conditions on primordial Earth.
Scientists said an analysis of gas bubbles trapped in ancient basalt rock that formed from ancient lava flows in western Australia showed the planet back then possessed a much thinner atmosphere, with air pressure half of what it is today.
That finding contradicts a long-held notion that Earth then had a thicker atmosphere to compensate for a fainter sun, with sunlight about 15 percent dimmer. The sun is slowly brightening over time, part of a star's natural evolution.