The chemistry of meteorites and planets allows us to link things together and understand more of our solar system’s history and help us maybe survive exploring that solar system.

One of the biggest mysteries of our solar system’s formation is how Earth ended up with so much water. There is a hypothesis that some if not all of the water came from asteroids that hit the Earth during a period known as the late heavy bombardment. You see, those asteroids formed out beyond the ice line, meaning that instead of dealing with gaseous or liquid forms of H20 and carbon dioxide, these bodies were infused with frozen forms. And when a bunch of them collided with the youngish Earth, all that ice was heated up and released in liquid form, or possibly gaseous form, and held onto by Earth’s gravity. That’s good for us, since we require said water to live.

And now, an analysis of the Sutter’s Mill meteorite has provided a bit more evidence for the “water and carbon dioxide came here from afar” hypothesis. The meteorite fell to Earth back in 2012, and due to witness accounts of the fireball and radar data, several pieces were found by my SETI Institute mentor, Peter Jenniskens. Now a team has analyzed some of the tiniest inclusions in the minerals of the meteorite — frozen bits that were trapped inside and are now liquid but still trapped — and they found carbon dioxide-rich water.

Per the press release: This would require the asteroid to have formed in a part of the solar system cold enough for water and carbon dioxide to freeze, and these conditions would place the site of formation far outside of Earth’s orbit, likely beyond even the orbit of Jupiter. The asteroid must then have been transported to the inner regions of the solar system where fragments could later collide with the planet Earth.

More Information

Ritsumeikan University press release

“Discovery of primitive CO2-bearing fluid in an aqueously altered carbonaceous chondrite,” Akira Tsuchiyama et al., 2021 April 21, Science Advances