Studying grains of material from an asteroid called 25143 Itokawa brought back to Earth by a Japanese robot probe, this group of scientists concluded that these grains support the hypothesis that our oceans came from outer space. Photograph:( Others )
Ice from comets and asteroids crashing on Earth would have made an equally substantial contribution. According to Lee, solar dust and icy comets provided us with the oceans in which life then evolved
We live on a planet 71 per cent of which is covered in water. It is the water that gives Earth its unique blue colour from space; but the origin of this liquid water, which sustains our seas and has nourished life for millennia, still remains a subject of intense debate.
Some researchers argue that water in one form or the other has been present in our world ever since it coalesced out of swirling clouds of dust and gas 4.5 billion years ago. Earth has always been provided with a reservoir, in short.
Yet, other scientists have a different and, frankly, much more interesting viewpoint.
According to them, Earth was once parched and almost waterless, and our oceans were merely the result of ice and water raining down from extraterrestrial sources.
Yes, aliens gave us water! The theory suggests that extraterrestrials may be responsible for most of the 332,500,000 cubic miles of water covering our planet today.
And...drumroll, please...now, British scientists are backing up the hypothesis that our seas are actually from "out of this world."
Studying grains of material from an asteroid called 25143 Itokawa brought back to Earth by a Japanese robot probe, this group of scientists concluded that these grains support the hypothesis that our oceans came from outer space.
Luke Daly, of the University of Glasgow, says that the dust they studied provides compelling evidence that our oceans were formed from water from other parts of the solar system. He says that there is strong evidence that at least half of the water on Earth has been filtered by interplanetary dust.
The scientists report in a paper published in Nature Astronomy that the grains brought back from the asteroid contained a significant amount of water. Daly and his colleagues examined grains of dust returned from Itokawa 25143 using atom-probe tomography. By using this technique, scientists can count atoms one by one in a sample.
As Daly explains, this water was most likely created by the solar wind, a stream of particles emanating from the Sun. In the clouds of dust that float throughout the solar system, these particles would have interacted with oxygen atoms to create water molecules which would have built up in the clouds over the solar system's history.
The dust grains, as well as their water, would have been mopped up by the Earth as it orbited the Sun. According to an argument, this would have allowed water, which Leonardo da Vinci once called "the driving force of all nature," to filter down from the skies onto the earth.
Professor Martin Lee of the University of Glasgow, who was part of the group, stressed that all the water that is found in our seas did not come from solar dust grains.
Ice from comets and asteroids crashing on Earth would have made an equally substantial contribution. According to Lee, solar dust and icy comets provided us with the oceans in which life then evolved.
This discovery is important not only for providing compelling evidence about the origins of water on Earth, but for several other reasons as well. It implies that there may be water on other worlds in our solar system, perhaps in the form of ice. This has profound implications for future exploration of space and the hunt for life across the universe.