We don't know where all our water came from because Earth is our Solar System's bluest planet.
The Sun is a potentially overlooked source, thanks to the dust of a nearby asteroid.
It seems that some water on our planet might have been created by a river of charged particles blowing from the upper atmosphere of the Sun billions of years ago.
Some of the liquid we find here on our planet could be explained by the small amount of water created by solar wind interacting with the tiny dust particles on certain asteroids.
Most modern models suggest the majority of H20 on Earth came from an extraterrestrial source.
The parent bodies of carbonaceous chondrite meteorites that crash into Earth are thought to be these far-away asteroids.
Water may have been delivered to Earth in other ways, such as carbonaceous chondrites. Since carbonaceous chondrites can't account for Earth's entire water budget, other types of water-rich meteorites could have also done the same.
There are other types of chondrite asteroids that could have held water. An analysis of samples taken from the Itokawa asteroid in 2010 found signs of water, and it is possible that the source is the Sun.
Water can be formed on silicate-rich materials floating in space by using solar wind irradiation.
In the lab, volatile hydrogen ion have been shown to react with silicate minerals, resulting in water as a byproduct, and in the past, direct evidence of H20 has been found within extraterrestrial dust particles.
Water can be delivered via meteorites to other bodies in space if it becomes trapped in the dust particles.
The authors of the new study say that the phenomenon could explain why the regoliths of airless worlds such as the Moon contain H20.
Researchers looked at the S-type asteroid, Itokawa, to see if it had a 'volatile reservoir' of isotypes similar to that of solar wind.
While most water isotypes on Earth match carbonaceous chondrites, a small percentage don't, and the Sun or the solar nebula have been proposed as possible sources.
Scientists have measured the amount of water found in the dust from the Itokawa asteroid using atom probe tomography, a method of analyzing atom-by-atom.
The team found water and hydroxide in the rims of the particles. This suggests that the Sun's hydrogen ion was put into the rock to store the water.
The depth at which these life-giving elements were found was exactly what scientists would expect from hydrogen ion penetrating silicate materials.
Phil Bland, a planetary scientist from Australia, says that the solar wind created water on the surface of tiny dust grains and that this water likely provided the rest of the Earth's water.
The team estimates S-type asteroids can hold 20 liters of H20 for every square meter of rock.
If we collect enough of the isolated grains of dust in space, we could potentially harvest them for water in the future, which would be an important source of water in our Solar System.
One of the barriers to future space exploration is how astronauts would get enough water.
The same space weathering process that created water on Itokawa may be the same one that created water on other airless planets, meaning astronauts may be able to process fresh supplies of water straight from the dust on a planet's surface, such as the Moon.
The Sun could be giving us more than one thing.
Nature Astronomy published the study.
