A new Curtin University study solves the long-standing mystery of Earth’s water source.
Curtin University researchers have contributed to unraveling the ongoing mystery of the Earth’s water origins, identifying the Sun as an unexpectedly likely source.
A research team led by the University of Glasgow and including members of Curtin’s Space Science and Technology Centre (SSTC) discovered that the solar wind, which is composed primarily of charged particles from the Sun, created water on the surface of dust grains carried by asteroids that collided with the Earth during the early days of the Solar System.
Distinguished SSTC Director, John Curtin Professor Phil Bland explained that the Earth was unusually water-rich in comparison to other rocky planets in the Solar System, with oceans covering more than 70% of its surface, and scientists had long debated the exact source of all that water.
“An existing theory is that water was carried to Earth in the final stages of its formation on C-type asteroids, however previous testing of the isotopic ‘fingerprint’ of these asteroids found they, on average, didn’t match with the water found on Earth meaning there was at least one other unaccounted for source,” says Professor Bland.
“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.
“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.
“Our world-class atom probe tomography system here at Curtin University allowed us to take an incredibly detailed look inside the first 50 nanometres or so of the surface of Itokawa dust grains, which we found contained enough water that, if scaled up, would amount to about 20 litres for every cubic metre of rock.”
Dr Luke Daly, a Curtin graduate currently at the University of Glasgow, said the research not only provides scientists with unprecedented insight into the ancient supply of Earth’s water, but also has the potential to benefit future space missions.
“How astronauts would get sufficient water, without carrying supplies, is one of the barriers of future space exploration,” says Dr Daly.
“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.”
Image Credit: iStock
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