The Sun and asteroids that have passed close to Earth may be responsible: water on Earth, now we know where it comes from
Why is our planet habitable and others - perhaps - not? It is a combination of elements that depend on the distance from the Sun, the size and the speed of rotation around its axis. But it also depends on the presence of certain elements on Earth: nitrogen, oxygen, carbon dioxide and, above all, water in a liquid state.
But how did water form on our planet, 4 billion years ago? One hypothesis is that something brought it to us: according to scientists, the solar wind. We mentioned it when we talked about the fascinating theory on the origin of everything, below we go to deepen.
The arrival of water on Earth
Over the years there have been many theories about how water appeared - or arrived - on our planet, billions of years ago. According to one of these theories, it was brought by carbonaceous asteroids, but their isotopes don't exactly match those of our water.
There is, however, a new, very recent theory. Our flagship star, the Sun, emits some very important chemicals into the atmosphere surrounding it - which are not only responsible for potential damage. Among them is hydrogen, or rather hydrogen ions.
These ions have settled, over millennia, on the dust grains of the asteroids that have passed close to Earth. There they met silicates, a class of minerals, along with which they precipitated onto our planet.
The Scientists' Study
An international team of astrophysicists has just published the discovery in the scientific journal Nature Astronomy, after conducting a study of the stony, S-type silicate-rich asteroid Itokawa. Samples of this celestial body were brought ashore by the Japanese probe Hyabusa, and were analyzed atom by atom.
A state-of-the-art tomography system was used, which allowed the samples to be analyzed layer by layer. In this way they were observed in detail 50 nanometers of the surface of Itokawa: "we found that contained an amount of water that, proportionally, could amount to about 20 liters per cubic meter of rock," said Philip Bland, one of the researchers who worked on the project.
The study could have important implications for the supply of water for space missions in the future. It also shows that just as water formed on the asteroid Itokawa, which has no atmosphere, it could happen on other celestial bodies without an atmosphere. That means astronauts could get water from surface dust, even on the Moon - one of the goals that scientists around the world are most focused on, and making strides toward.