Quirks & Quarks

Solar wind and space dust may explain the presence of much of Earth's water

Researchers have found evidence that particles emitted by the sun may have combined with space dust on asteroids to contribute to our seas and oceans.

Study found asteroid rock could hold up to 20 litres of water per cubic meter

Solar winds are streams of hydrogen and helium ions flowing constantly out of the sun. When those hydrogen ions hit space dust or asteroids, they can break chemical bonds and interact with oxygen that's present in the rock to create water. (BRIAN BIELMANN/AFP via Getty Images)

Researchers have found evidence that particles emitted by the sun may have helped give Earth its seas and oceans.

The international team of researchers studied dust from an ancient asteroid, and found evidence that "solar wind" — charged hydrogen particles streaming out from the sun — may have combined with dust grains to create water, which would have then travelled to Earth after the planet's formation 4.6 billion years ago.

"Our results suggest that somewhere between 50 and 75 per cent by mass of the water [on Earth] needs to come from solar wind water, in order to match or reproduce what we see in the Earth's oceans," said Hope Ishii, one of the authors of the paper. 

"You can imagine that when you pour yourself a glass of water, about half of that is actually coming from sun plus rock."

In the new study, researchers studied samples from an asteroid called Itokawa, collected by the Japanese space probe Hayabusa in 2010. They used a high-tech imaging system called atom probe tomography to take a detailed look inside the asteroid dust, measuring the atomic structure one atom at a time. In these dust grains they found a significant amount of water.

Ishii is a research professor with the Hawaii Institute of Geophysics and Planetology at the University of Hawai'i at Mānoa. You can listen to her full conversation with Bob McDonald at the link above.

Produced by Amanda Buckiewicz


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