SCIENCE

Asteroid Impacts 3.3 Billion Years Ago Caused Earth's Oceans To Boil

05/28/2015 05:43 am ET | Updated May 28, 2015
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Don't complain too much when temperatures rise this summer, because it used to be worse. A lot worse.

Some 3.3 billion years ago, monster asteroids -- in some cases bigger than Rhode Island -- repeatedly slammed into the Earth with impacts so violent that air temperatures soared to 932 degrees Fahrenheit for weeks at a time, according to a new study published in the journal Geology.

Temperatures rose to such extreme levels that the oceans literally boiled, causing sea levels to drop by about 330 feet.

Yet somehow, early life managed to survive.

These impacts would have a profound influence on any life trying to evolve into more complex, low-temperature organisms,” geologist Donald Lowe of Stanford University, who led the research, told Science News. “They’d keep getting whacked by these giant impactors and driven to extinction or near extinction.”

Lowe and study co-author Gary Byerly of Louisiana State University made the discovery while examining the Barberton Greenstone belt in South Africa, where ancient rock is exposed.

There they found evidence that the Earth was hit by eight monster asteroids ranging in size from about 12 miles wide to about 60 miles wide over the space of 250 million years, Ars Technica reports.

By comparison, the asteroid commonly blamed for the mass extinction that wiped out the dinosaurs was "only" about 6 miles wide.

The 932-degree temperatures and boiling oceans would support a theory that all modern life is descended from thermophiles (organisms that thrive in extreme heat), as anything that preferred the cold would have been wiped out, according to Science News.

“You can picture these asteroids as a crazed tree trimmer showing up and chopping branches off the tree of life," planetary scientist Kevin Zahnle of the NASA Ames Research Center told the website.

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