The building blocks of life came to Earth earlier than thought

When did water first form on Earth? Meteorites containing important elements brought the makings of water to a very early Earth, but there’s still some speculation as to when exactly that happened.

It was previously thought that the Earth was initially dry, as the volatile beginnings of the planet would have made it impossible for water to congregate and stay put.

However, a new study shows that water may have come to Earth much earlier than was thought, during the first two million years of the solar system.

Researchers from the Massachusetts Institute of Technology analyzed angrite meteorites to help create a more accurate picture of when the first life sustaining elements came to Earth.

Angrite meteorites are basaltic meteorites that formed in the inner solar system about four and a half billion years ago. The researchers analyzed the meteorites noting the volume of hydrogen and carbon inside the space rocks.

By studying the meteorites themselves, the researchers were able to create a better understanding of the parent body that the meteorites originated from.

The study was published in the journal Geochimica and Cosmochimica Acta.

“We’re looking at as many meteorite parent bodies as possible right now to figure out where they were in the early Solar System and how much water they had,” said Adam Sarafian, the leader of the study in an interview with Astrobiology Magazine. “We’re trying to build a map of the very early inner Solar System. Where was the water, where was it going and where did it come from?”

In this case, the angrite meteorites all came from one parent asteroid that had a high water content, roughly 20 percent of the Earth’s current water content.

This means that water could be found during the solar system’s early beginnings, and angrite meteorites coming from a water-rich parent body likely brought the necessary elements for water and life to Earth earlier than was previously theorized.  

“It’s a fairly simple assumption to say that Earth’s water at least started accreting to Earth extremely early, before the planet was even fully formed,” said Sarafian. “This means that when the planet cooled enough so that liquid water could be stable at the surface, there was already water here.”

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By Kay Vandette, Earth.com Staff Writer