Our planet is covered in water: 以上で 70 per cent of its surface made up of oceans, it is far more water-rich than other planets in our solar system. But scientists have long struggled to know where all of that has come from.
Now a new study has suggested that surprising possibility that it came to Earth from the Sun.
「既存の理論では、水はC型小惑星での形成の最終段階で地球に運ばれたというものです。, しかし、これらの小惑星の同位体「指紋」の以前のテストでは、それらが見つかりました, 平均して, 地球上で見つかった水と一致しませんでした。つまり、他に少なくとも1つの原因不明の水がありました。,フィル・ブランド, a professor at Curtin University and one of the scientists involved in the study, 声明で言った.
“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.”
The research could not only prove useful in telling the story of our Earth, but helping us leave it, 科学者は言う. We might be able to use the same technique in future space missions.
“How astronauts would get sufficient water, without carrying supplies, is one of the barriers of future space exploration,” said Luke Daly, another scientist who worked on the paper.
“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.”
調査結果を説明する論文, ‘Solar wind Contributions to the Earth’s Oceans’, で公開されています ネイチャーアストロノミー.