An international team of researchers led by the University of Glasgow suggests that much of the Earth's water could be formed by solar winds. A corresponding study was published in Nature Astronomy.
The Earth is a very water-rich planet compared to other rocky planets of our solar system – oceans cover over 70 percent of the Earth's surface. Scientists have long thought about the origin of water on our planet. The existing theory states that water was delivered to Earth on asteroids during the last stages of its formation.
However, this could not explain why there is so much water on the planet. Previous studies also showed that the isotopic composition of terrestrial and asteroid water was different, meaning that there could be at least one other water source, one of the study participants, Professor Phillip Bland, said.
A group of scientists analyzed fragments of the Itokawa asteroid, which was delivered to Earth by the Japanese Hayabusa spacecraft in 2010. The team unexpectedly found many water molecules among the dust that covered the asteroid, and this water's isotopic composition was very similar to that extracted from the Earth's mantle.
As it turned out, the upper layer of the cosmic dust particles that covered the asteroid's surface actively interacted with the solar wind, forming water. Therefore, scientists suggest that this water then hit the surface of the Earth with asteroids, which crashed into the planet in the early days of the solar system's existence.
Scientists suggest that this discovery could enable astronauts to extract water from dust on the surface of the Moon and other celestial bodies.