Earth is the bluest planet in our solar system, and yet no one knows where all our water came from.
Dust from a nearby asteroid has now revealed a potentially overlooked source: the Sun.
It seems that some of the water on our planet could have been created by a river of charged particles carried away from the upper layers of the Sun’s atmosphere billions of years ago.
When the solar wind interacts with tiny dust particles found on certain asteroids, it can create a small amount of water, and this may explain some of the liquid we find here on our planet.
Most modern models offer most H20 on Earth originally came from an extraterrestrial source, possibly from C-type asteroids in the Jupiter-Saturn region and beyond.
These distant asteroids are believed to be the parent bodies of carbonaceous chondritic meteorites that regularly crash into Earth, and this particular type of meteorite is known to contain significant amounts of water-containing minerals.
But carbonaceous chondrites are probably not the only way water gets to Earth. Other types of water-rich meteorites could also do the same, especially since carbonaceous chondrites cannot account for the entire water balance of the Earth.
There are other types of chondritic asteroids that may have retained water particles as well, albeit to a lesser extent. For example, the near-Earth asteroid Itokawa is a common chondritic asteroid, and analysis of samples taken from this silicate-rich rock in 2010 revealed signs of water, and the Sun may well be the source.
In the past, exposure to solar wind has been suggested as a possible way to form water on silicate-rich materials floating in space.
In the laboratory, volatile hydrogen ions have been shown to react with silicate minerals to produce water as a by-product, and electron microscopy and electron spectroscopy studies have found direct evidence for the presence of H20 in particles of extraterrestrial dust in the past.
In theory, if water gets trapped in these dust particles, the element will be protected from cosmic weathering and can then be transported via meteorites to other bodies in space.
“This phenomenon may explain why regoliths of airless worlds like the Moon, which were once thought to be waterless, contain several percent H20 “, – explain the authors of the new study.
To explore this hypothesis further and in a slightly different way, the researchers turned to the S-type asteroid Itokawa to see if the object contains a “volatile reservoir” of isotypes similar to that of the solar wind.
While most water isotypes on Earth correspond to carbonaceous chondrites, a small percentage do not, and the Sun or solar nebula have been suggested as possible sources.
Based on a thorough atomic analysis known as atomic probe tomography, scientists have now measured the amount of water found in the dust from the asteroid Itokawa, which was returned to Earth by the Japan Aerospace Exploration Agency (JAXA) in 2011.
By measuring everything around these particles, including parts hidden from the Sun, the team found hydroxide and water enriched with rims on all sides. This suggests that the Sun’s hydrogen ions have been “implanted” into the rock, keeping water where it cannot be touched.
The depth at which these life-giving elements were found was exactly what scientists expected from the penetration of hydrogen ions into silicate materials.
“Our research shows that the solar wind created water on the surface of tiny dust particles, and this isotopically lighter water probably provided the rest of the water on Earth,” says planetary scientist Phil Bland of Curtin University in Australia.
Based on how much water they found in these tiny dust particles, the team estimates that S-type asteroids may contain 20 liters of hydrogen.20 for every cubic meter of rock.
The findings suggest that isolated dust grains in space could represent an important source of water in our solar system that we could potentially collect in the future if we collect enough of them.
“How astronauts get enough water without carrying supplies is one of the obstacles to future space exploration,” says geologist Luke Daly, who worked on the analysis at Curtin University.
“Our research shows that the same process of cosmic weathering that created water on Itokawa probably happened on other airless planets, which means that astronauts can process fresh water directly from dust on the surface of a planet like the Moon.”
The sun could give us life in several ways.
Research published in Nature Astronomy…