Solar ions could flow on Earth
Experts say the Sun may be a major source of water on Earth.
Earth is very water-rich compared to other planets in the Solar System, with oceans covering more than 70 per cent of its surface.
Curtin University researchers have helped unravel the enduring mystery of the origins of the Earth’s water, and found what might be a surprising source.
Researchers from Curtin’s Space Science and Technology Centre (SSTC) say solar wind - composed of charged particles from the Sun including hydrogen ions - creates water on the surface of dust grains.
These grains appear to have been carried on asteroids that smashed into the Earth during the early days of the Solar System.
“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,” SSTC Director Professor Phil Bland says.
“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.”
The SSTC team took a detailed look inside the first 50 nanometres of the surface of Itokawa dust grains.
They found the grains contained enough water that, if scaled up, would amount to about 20 litres for every cubic metre of rock.
Researcher Dr Luke Daly says the study 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,” Dr Daly says.
“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.”