Atmosphere of early Earth may have been half as thick as today

Bubbles in ancient Australian lava reveal that the early Earth's atmosphere might have been half as thick as it is today, scientists say.

The findings contradict the decades-long belief that Earth's early atmosphere was thick and, if confirmed, would expand the list of the types of planets capable of supporting life, the researchers said in a new study.

Even so, other Earth scientists say the claim is sure to be controversial.

"Here you have a young Earth with an atmosphere completely different than today, and yet was very much alive," lead study author Sanjoy Som, director of the Blue Marble Space Institute of Science, told Live Science in an email. At the time, some 2.7 billion years ago, the Earth was spinning faster, and its newly formed moon raised much higher tides than Earth experiences today, Som said. It also may have been exposed to more ultraviolet light, as there was not yet an ozone layer. "[That] makes the early Earth the closest thing we have to an inhabited exoplanet [a planet outside our solar system]," Som added.