Asteroid dust collected by the Japanese space probe contains organic matter, suggesting that some of the building blocks of life on Earth may have formed in space, scientists say.
Pristine material from asteroid Ryugu is returned to Earth in 2020 after a six-year mission to the celestial body some 300 million kilometers away.
But scientists are just beginning to uncover its secrets in early studies of tiny fractions of 5.4 grams (0.2 ounces) of dust and small, dark rocks.
In a paper published Friday, a team of researchers led by Okayama University in western Japan say they have discovered “amino acids and other organic substances that may provide clues on the origin of life on Earth”.
“The discovery of protein-forming amino acids is important, because Ryugu has not yet been exposed to Earth’s biosphere, like meteorites, and as such their discovery demonstrates that at least some The building blocks of life on Earth may have formed in space, the study said.
The team says they found 23 different amino acids while examining samples collected by the Japanese Hayabusa-2 probe in 2019.
Dust and rock were stirred up when the refrigerator-sized spacecraft fired an “agent” at the asteroid.
“The Ryugu specimen has the most primitive features of any natural specimen available to mankind, including meteorites,” the Japan Aerospace Exploration Agency (JAXA) said in a statement.
It is believed that part of the matter was created about five million years after the birth of the solar system and has not been heated above 100 degrees Celsius (210 degrees Fahrenheit).
Another study published in the US-based journal “Science” says the material has “a chemical composition closer to that of the Sun’s photosphere than other natural samples”.
Kensei Kobayashi, an astrophysicist and emeritus professor at Yokohama National University, praised the discovery.
“Scientists have questioned how organic matter – including amino acids – is made or where it comes from, and the fact that amino acids were detected in the sample provides a rationale. do to think that amino acids were brought to Earth from space,” he told AFP.
Another dominant theory about the origin of amino acids is that they were created in the Earth’s primordial atmosphere through lightning strikes, such as after the Earth cooled.