Key Highlights:
- An international team of scientists led by the University of Glasgow has postulated that the Sun may be a key source of our planet’s H2O.
- One of the more prevalent hypotheses is that it arrived on Earth shortly after its formation in the form of a constant shower of C-type or carbonaceous meteorites.
- The findings indicate that the solar wind formed water on the surface of microscopic dust grains and that this isotopically lighter water likely provided the rest of the Earth’s water.
Sun may be responsible for some of Earth’s water
Accounting for where all of the Earth’s water originated from has long been a mystery, but an international team of scientists led by the University of Glasgow has postulated that the Sun, via hydrogen from the solar winds, may be a key source of our planet’s H2O.
The Earth is the solar system’s actual outlier. The Earth’s surface is three-quarters covered by massive oceans of liquid water, unlike all the other tiny, stony planets. Where did this water originate from is the question.
One of the more prevalent hypotheses is that it arrived on Earth shortly after its formation in the form of a constant shower of C-type or carbonaceous meteorites, which vary from regular meteorites in that they contain the hydrogen and oxygen required to generate water.
It’s a plausible idea that fits with what we know about such meteorites, but there’s a catch. Because the ratio of hydrogen isotopes in carbonaceous meteorites does not match those found in terrestrial water very well, what is the alternative?
Revelations made through findings
“An existing theory is that water was carried to Earth in the final stages of its formation on C-type asteroids,” says University of Curtin Professor Phil Bland, one of the Glasgow team. “However, the previous testing of the isotopic ‘fingerprint’ of these asteroids found they, on average, didn’t match with the water found on Earth, implying there was at least one other unaccounted for source.”
The findings indicate that the solar wind formed water on the surface of microscopic dust grains and that this isotopically lighter water likely provided the rest of the Earth’s water. This new solar wind idea is based on an atom-by-atom examination of microscopic shards of Itokawa, an S-type (stony) near-Earth asteroid retrieved by the Japanese space probe Hayabusa and returned to Earth in 2010.
“Our world-class atom probe tomography system here at Curtin University enabled us to take an incredibly detailed look inside the first 50 nanometers or so of the surface of Itokawa dust grains, which we discovered contained enough water to amount to about 20 liters (4.4 gals) for every cubic meter of rock if scaled up.”
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