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Japanese scientists have discovered new evidence on the asteroid Ryugu that could help better understand the history of water in the solar system and the possibility of life beyond Earth.
Dust samples from asteroid 162173 Ryugu obtained by the spacecraft Hayabusa2 in 2018, revealed the fascinating chemical history of this celestial body. Several types of salt crystals were found among the collected particles, including sodium carbonate, halite, and sodium sulfates, suggesting that Ryugu was once part of a larger object that contained warm salt water. Using advanced analysis techniques such as X-ray tomography and scanning electron microscopy, the researchers were able to identify these salt minerals, providing new insights into the asteroid's past.
Ryugu, now a 900-meter asteroid in the Apollo Belt, contains no water today, but research suggests it was once part of a parent body that existed about 4,5 billion years ago. This body likely contained liquid salt water, which could have been preserved by radioactive decay and high temperatures in the interior. But later, as the body cooled, the water could have evaporated, frozen, or escaped into space through cracks in the body.
"The salt minerals we found are the crystallized remains of that water," "These results confirm that Ryugu once had some amount of liquid that was saturated with salt, and this could help in understanding how other celestial bodies like Ceres, Europa, Ganymede and Enceladus could have had water in the past," explains Toru Matsumoto of Kyoto University.
Comparing the salt minerals found on Ryugu with other astronomical objects could shed light on the role of water in the formation of life beyond Earth, as well as expand our knowledge of the conditions that could support the development of life in the far reaches of the solar system.
