The Sun played a decisive role in the arrival of water on Earth

Our knowledge of the origin of water on Earth is still lacking, but a team of researchers seems to have found the missing piece of the puzzle.

The major peculiarity that makes our earth so unique and earned it its nickname of Blue Planet, it is obviously the water which covers nearly three quarters of its surface. But at present, the scientific community has no certainty about its origins. Astronomers have long suspected that it must have been deposited on Earth by meteorites, but there is still part of the equation missing; an international team of researchers now believes that solar winds could have played a decisive role.

The meteorite track has shown itself to be particularly promising and coherent from the first studies on the subject; astronomers soon realized that meteorites (or rather a particular type, carbonaceous chondrites) were surprisingly rich in water. But they quickly realized that everything didn’t fit perfectly; even if it was very close, the composition of this “extraterrestrial” water presented some differences compared to the chemical signature of the terrestrial water. However, these differences can only be explained by the existence of another source which therefore remained to be identified.

When the cosmic dust is sunbathing

In recent work spotted by Futura, Luke Daly’s team now thinks they’ve got their hands on one of the missing pieces of the puzzle. By studying a speck of dust brought back by the Japanese probe Hayabusa, they noticed an unexpected phenomenon; under the effect of the solar wind, about 2% of each speck of dust would have turned into water. This reaction would be due to the fact that the solar wind is largely composed of hydrogen ions. When that wind hits grains of rock dust in space, these ions react with oxygen it contains to form water. This would then have found itself trapped in the Earth’s atmosphere under the effect of gravity.

An explanation that apparently ticks all the boxes. According to all current models, before the formation of massive celestial bodies stabilized the entire system, this dust was exceptionally abundant in the universe; so there was enough to form a large amount of water. There is also another clue which makes this explanation particularly satisfactory. If we mix the water from carbonaceous chondrites with that which comes from the reaction between solar winds and dust, we obtain a chemical signature that perfectly matches that found on Earth.It is very impressive” Enthuses chemist Ashley King in an interview with New Scientist. “We can show that by mixing these two reservoirs, we obtain a very good correspondence with the oceans of the Earth ”.

A way to produce water far from the Earth?

For the researchers, the next step will be to analyze other samples. The objective will thus be to confirm their hypothesis with new observations. They have high hopes for the analysis of samples from the asteroid Ryugu, which the Hayabusa 2 probe brought back in 2020. And if these results support their theory, it could have far-reaching implications on many levels.

Because in addition to the implications in basic research, it could have much more concrete implications. This information could in particular change the way we view the exploitation of resources in our future colonies. “If we want to set up permanent dwellings in other worlds, we might be interested in producing water from dust.”, Concludes Daly.

The text of the study is available here.

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