[cleanair (OP)]

I recently noticed a news article that indicated that water on Earth could have originated from the Sun.

Sun is likely an unaccounted source of the Earth’s water
https://www.sciencedaily.com/releases/2021/11/211129122755.htm

Question: what percentage of water on Earth could have originated from the Sun?

[evan_au]

what percentage of water on Earth could have originated from the Sun?

Very little, as water.

Water is composed of hydrogen and oxygen - the Sun is mostly hydrogen, but a comparatively small amount of oxygen.
- What these researchers are suggesting is that the Sun contributed hydrogen, via the Solar wind
- And the asteroids contributed oxygen, via silicate minerals.

Some water would also have arrived from comets and icy asteroids.

[cleanair (OP)]

Thank you for the reply!

With regard the source of oxygen. A recent study discovered that rocks and minerals on Earth developed the first photosynthesis to produce oxygen.


mineral.jpg (134.77 kB . 896x898 - viewed 927 times)

(2021) Non-classical photosynthesis by earth's inorganic semiconducting minerals
Our work in this new research field on the mechanisms of interaction between light, minerals, and life reveals that minerals and organisms are inseparable. ... producing hydrogen and oxygen
https://phys.org/news/2021-01-non-classical-photosynthesis-earth-inorganic-semiconducting.html

The question: how much hydrogen that is part of the water on Earth could have originated from the Sun? Could it explain the oceans?

[chiralSPO]

That semiconducting minerals could (be) have been involved to some extent in light-driven chemical reactions is unsurprising. (physics is the same in the lab and the ground). But it's interesting to think of this process as a precursor to photosynthetic organisms.

But, it's not at all relevant to the initial question or evan_au's response. I think you may be confused by the double meaning of the word oxygen. Photosynthetic organisms produce the molecular form of oxygen, O₂, which is the primary form of "oxygen" in our atmosphere. But the oxygen atoms (also called "oxygen") were already in the environment, just not as O₂. Almost 1/2 of the mass of the crust is oxygen, but it's combined with other elements into compounds like water, silicates, aluminates, carbonates etc.

This oxygen did not come from the sun.

I would not be terribly surprised if a significant amount of the hydrogen atoms on Earth had come from the sun. Since atomic hydrogen and H₂ (the most common forms of hydrogen in the primordial solar system, as I understand it) are too light to have been gravitationally captured by earth (as it was forming, or since). The next most common forms, water (H₂O, ammonia (H₃N), and methane (H₄C), are all heavy enough to stick around, but I don't think would have given the right ratios of hydrogen to these other elements (someone can check me on this, my confidence on this point is not very high).