Hollywood has given asteroids a bad name. When one goes against the Earth it is only expected that some NASA luminary avoid the orgy of death and destruction. It is likely that dinosaurs attested to the justice of this reputation, but there is growing evidence that without these objects there would have been no life to destroy on Earth.
The most accepted theories suggest that 3,900 million years ago the Earth suffered an intense bombardment of asteroids or comets. Only 400 million years later, a sigh in geological terms, the first living beings appeared. The basic ingredients for life, particularly large amounts of water, but also nitrogen, carbon and other organic materials, would have traveled aboard a type of meteorite known as carbonaceous chondrites.
To reach these conclusions about such remote events, scientists have accumulated evidence scattered throughout the cosmos, as the similarities between the atmosphere of our planet and Titan, the distant moon of Saturn where the seas are methane. But to complete the story about this fundamental stage of the history of terrestrial life, information was missing on-site. That information was obtained 14 years ago, in the asteroid Itokawa, but it has taken time to know that it was there.
The exploration trip, which like many projects of this type is a time machine, began in 2003 when the Japanese space agency (JAXA) launched the probe Hayabusa, a mission that brushed the disaster on several occasions. It arrived in Itokawa in 2005 and landed on its surface twice to take samples of its soil. Then, it took off again to return to Earth with its valuable cargo.
At the time, the dust collected by Hayabusa It confirmed that Itokawa was an S-type asteroid, the main source of the meteorites that most frequently reach Earth. Now, in a study recently published in the journal Science Advances, Ziliang Jin and Maitrayee Bose, two researchers from the Arizona State University (USA), have used a few particles of the collected by Hayabusa to conclude that Itokawa and the asteroids in its category contain large amounts of water. According to them, half of the water in Earth's oceans arrived in this type of celestial objects billions of years ago.
The mission of Hayabusa He tried to analyze the asteroid because it is believed that these objects are loose remains that remained of the formation of the solar system. In a way, they are fossils from that primordial time and can help us understand what our environment was like billions of years ago. Despite its aspect of desert rock, the information extracted from its surface indicates that it contains more water than usual for the bodies that orbit the inner part of our planetary system.
The samples analyzed had a thickness less than half of a human hair
The task of Jin and Bose required extreme precision. JAXA only gave them five tiny samples, less than half the size of a human hair. To analyze them, they used a type of nanometric mass spectrometer that allows analyzing the composition of tiny mineral grains with great sensitivity. In a statement from his institution, Jin said that "although the samples were collected from the surface, we do not know where they were in the original object (Itokawa was detached from a larger asteroid), but our best estimate is that he was buried 100 meters deep. Now, the asteroid, which orbits between Earth and Mars, circling the Sun every 18 months, has a diameter of just over 300 meters and a length of 500 meters.
The presence of water in the solar system has been confirmed with observations through telescopes and with the collection of samples by probes in recent years. The Moon or Mars harbor large amounts of water, mainly in the form of ice, but also liquid. The first time water was found in an asteroid was in 2010, when a team of researchers using NASA's Infrared Telescope in Hawaii identified signs of ice and organic material. In December of last year, the OSIRIS-REx mission found hydrated minerals in the asteroid Bennu and the scientific consensus indicates that water is common in this type of objects.
The most striking thing about the water found in Itokawa is that its isotopic mark is identical to that of the Earth, a further indication that our oceans could be nourished by the bombardment of asteroids rich in the essential liquid for life.
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