Earth's water may have come from the Sun and space rocks

A team of researchers have analyzed samples from an asteroid and found evidence that suggests Earth's earliest water came from space rocks and the Sun.

The team of researchers published a paper in the journal Nature Astronomy, and it outlines an isotopic analysis of samples from the asteroid Itokawa. This asteroid orbits the Sun every eighteen months, and researchers were interested in its isotopic composition to answer the question about how Earth's surface became 70% water.

For some time, scientists have thought that carbon-rich asteroids brought water to Earth, but the chemical fingerprint of the asteroids didn't quite match Earth's, hence why researchers are looking into different asteroids. The researchers in the recently published study found that the interaction between solar wind that's constantly produced by the Sun and dust particles from the asteroid samples caused the earliest water to begin forming on Earth.

"[Our technique] lets us take an incredibly detailed look inside the first 50 nanometers [one inch has 24.5 million nanometers] or so of the surface of dust grains on Itokawa, which orbits the Sun in 18-month cycles. It allowed us to see that this fragment of space-weathered rim contained enough water that, if we scaled it up, would amount to about 20 liters [4.4 gallons] for every cubic meter [35 cubic feet] of rock.

That strongly suggests that fine-grained dust, buffeted by the solar wind and drawn into the forming Earth billions of years ago, could be the source of the missing reservoir of the planet's water, " said Phil Bland, the director of the Space Science and Technology Center at Curtin University in Australia and co-author of the study.

If these findings are proven true with additional studies, it will have overall bigger implications, as it will mean there are other planets out there beyond our solar system that have been beaten by the same kind of water-containing asteroids.

"One of the problems of future human space exploration is how astronauts will find enough water to keep them alive and accomplish their tasks without carrying it with them on their journey," said Hope Ishii, a geophysicist at the University of Hawai'i at Manoa and co-author on the study.