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Asteroid samples could reveal how Earth was formed

Ryugu is a near-Earth asteroid, with a diameter of 900 meters, that was first discovered in 1999 and was named after the undersea palace of the Dragon God in Japanese mythology. In 2014, the Japan Aerospace Exploration Agency (JAXA) launched Hayabusa 2 – an asteroid sample-return mission – to collect material samples from the asteroid’s surface and sub-surface. The spacecraft returned to Earth in 2020, with a collection of samples that were distributed around the world for scientific study. 

Now, an international team of researchers used UK’s national synchrotron facility Diamond Light Source to map out the chemical states of the elements collected from the asteroid and examine its composition in fine detail. Their findings could shed more light on the evolution of our solar system and the formation of the Earth.

The analysis revealed that the surface of Ryugu is dehydrated, most likely due to space weathering. This discovery led the scientists conclude that asteroids which appear dry on the surface may in fact be water-rich, a finding potentially requiring a significant revision of our understanding of the abundances of various asteroid types and the formation history of the asteroid belt.

According to the researchers, the building blocks of Ryugu are remnants of past interactions between water, minerals, and organic substances in the early solar system, prior to the formation of the Earth. Better understanding the composition of asteroids could thus help explain how the early solar system developed, and how the Earth formed afterwards. Moreover, since asteroids are believed to have delivered much of our planet’s water and organic compounds such as amino acids (which provide the building blocks of life), investigating the chemical composition of asteroids such as Ryugu could even clarify the origins of life on Earth.

“It’s important to build up experience in studying samples returned from asteroids, as in the Hayabusa2 mission, because soon there will be new samples from other asteroid types, the Moon and within the next 10 years Mars, returned to Earth,” concluded study co-author John Bridges, a professor of Planetary Science at the University of Leicester.   

The study is published in the journal Nature Astronomy.

By Andrei Ionescu, Staff Writer

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