An international team including researchers from the University of Glasgow, Scotland, and Curtin University, Australia, managed to unravel the enduring mystery of the origins of the Earth's water, finding the Sun to be a surprising likely source.
During the study, published in the journal Nature Astronomy on November 29, the team found the solar wind, comprised of charged particles from the Sun largely made of hydrogen ions, created water on the surface of dust grains carried on asteroids that smashed into the Earth during the early days of the Solar System.
Director of Curtin's Space Science and Technology Centre (SSTC) Professor Phil Bland said the Earth was very water-rich compared to other rocky planets in the Solar System, with oceans covering more than 70 percent of its surface, and scientists had long puzzled over the exact source of it all.
Our research suggests the solar wind created water on the surface of tiny dust grains and this isotopically lighter water likely provided the remainder of the Earth's water, he added.
This new solar wind theory is based on meticulous atom-by-atom analysis of miniscule fragments of an S-type near-Earth asteroid known as Itokawa, samples of which were collected by the Japanese space probe Hayabusa and returned to Earth in 2010.
The world-class atom probe tomography system at Curtin University allowed the researchers to take an incredibly detailed look inside the first 50 nanometers or so of the surface of Itokawa dust grains, which we found contained enough water that, if scaled up, would amount to about 20 liters for every cubic meter of rock.
Dr. Luke Daly, of the University of Glasgow, said “the research not only gives scientists a remarkable insight into the past source of Earth's water, but could also help future space missions.”
How astronauts would get sufficient water, without carrying supplies, is one of the barriers of future space exploration, Daly said.
"Our research shows that the same space weathering process which created water on Itokawa likely occurred on other airless planets, meaning astronauts may be able to process fresh supplies of water straight from the dust on a planet's surface, such as the Moon,” he added.
