A groundbreaking study suggests that ice on ancient asteroids like Ryugu played a crucial role in providing essential materials for life to early Earth.
The research, led by Dr. Matt Genge from Imperial’s Department of Earth Science and Engineering, analyzed samples from the Japanese space agency’s Hayabusa2 mission.
Scientists found evidence that freeze-thaw cycles fractured these asteroids, allowing water to interact with minerals and create organic matter.
The process may have been key to the emergence of life on our planet billions of years ago.
A groundbreaking study suggests that ice on ancient asteroids like Ryugu played a crucial role in providing essential materials for life to early EarthImperial/Getty
The research team – which includes collaborators at the Natural History Museum, the University of Kent and the Japan Aerospace Exploration Agency (JAXA) – discovered that rocks from the asteroid Ryugu showed evidence of fractures caused by ice.
These fissures were filled with clay and sulphide minerals, formed in the presence of water.
Dr. Genge explained: “Our calculations suggest that the pressure from the ice as it grows is sufficient to crack asteroids to their cores, allowing water to diffuse through them.”
This freeze-thaw process, where ice expands and contracts as it melts and refreezes, caused the rock to break apart.
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The specific shapes of the cracks on Ryugu could only have been formed by this process, rather than collisions with other asteroids.
The team conducted their research on a millimeter-sized piece of Ryugu brought back to Earth by JAXA. They used X-ray Computed Tomography (XCT), similar to a medical CT scan, to analyze the sample.
This technique allowed them to see the 3D shapes of the fractures on the asteroid. Researchers also found veins containing framboidal magnetite – small spherical crystals of magnetic iron oxide.
These discoveries provided further evidence for the presence of water on the asteroid. The characteristic curved shapes and points of the fractures and veins were crucial to understanding the role of the ice.
3D model of the mm-sized specimen of Ryugu, showing fractures in black and veins in blue
Imperial
Dr. Genge emphasized the importance of this process: “Our results suggest that the repeated melting and freezing of ice on asteroids may have helped form life on Earth.”
“The cosmic game of Rock, Scissors, Ice may well be a significant part of how life came to be,” concluded Dr. Gangs.
These results have been published in Nature Astronomy.