Asteroid dust collected by a Japanese space probe contains organic material that shows some of the building blocks of life on Earth may have formed in space, scientists said Friday.
Pristine material from the asteroid Ryugu was brought back to Earth in 2020 after a six-year mission to the celestial body some 300 million kilometers away, AFP said.
But scientists are only just beginning to uncover its secrets in early studies of small portions of the 5.4 grams (0.2 ounces) of dust and tiny dark rocks.
In a paper published on Friday, a group of researchers led by Okayama University in western Japan said they had discovered “amino acids and other organic matter that may give clues to the origin of life on Earth”.
“The discovery of protein-forming amino acids is significant because Ryugu has not been exposed to the Earth’s biosphere, such as meteorites, and as such their detection proves that at least some of the building blocks of life on Earth could have formed in outer space environments,” the study says.
The team said they found 23 different types of amino acids when examining the sample collected by Japan’s Hayabusa-2 probe in 2019.
Dust and rocks were stirred up as the fridge-sized spacecraft fired an “impactor” at the asteroid.
“The Ryugu sample has the most primitive characteristics of any natural sample available to mankind, including meteorites,” the Japan Aerospace Exploration Agency (JAXA) said in a statement.
Some of the material is thought to have been created around five million years after the birth of the solar system and was not heated above 100 degrees Celsius (210 degrees Fahrenheit).
Another study published in the American journal “Science” said the material has “a chemical composition that more closely resembles the Sun’s photosphere than other natural samples.”
Kensei Kobayashi, an expert in astrobiology and professor emeritus at Yokohama National University, hailed the discovery.
“Scientists wonder how organic matter – including amino acids – was created or where it came from, and the fact that amino acids were found in the sample offers reason to believe that the amino acids have been brought to Earth from outer space,” he told AFP.
Another common theory about the origin of amino acids is that they were created in Earth’s early atmosphere by lightning, for example, after the Earth cooled.