外媒：地球外首次确认“生命之源”，日本从小行星样本中发现20多种氨基酸

CD君 CHINADAILY

导读

据外媒当地时间6月6日报道，日本宇宙航空研究开发机构的小行星探测器“隼鸟2号”从小行星“龙宫”带回地球的沙子样本中，发现了“生命之源”——氨基酸，这是首次在地球以外确认氨基酸的存在。

▲ The first results from the initial description of the sample from asteroid Ryugu returned by the Hayabusa 2 spacecraft published in the British online journal, Nature Astronomy, December 21, 2021. /JAXA

The Japan Aerospace Exploration Agency (JAXA) probe Hayabusa 2 discovered "amino acids", the source of life, in sand samples brought back to Earth from the Ryugu asteroid, the Japanese financial newspaper The Nikkei reported on Monday, marking the first time that human beings have discovered amino acids, substances that make proteins, outside Earth.

More than 20 types of amino acids have been detected in samples Hayabusa 2 brought back to Earth from the Ryugu asteroid in late 2020, the newspaper quoted a Japanese education ministry official as saying. The official noted that amino acids, one of the first organic molecules to appear on Earth, are very important substances for living things and could hold clues to understanding the origins of life.

With amino acids essential for all living things to make proteins, the discovery could hold clues to understanding the origins of life, the Japan education ministry said.

▲ Japan's Hayabusa 2 space probe brought samples to Earth from the Ryugu asteroid in late 2020. /JAXA

Probe on origin of life

Hayabusa 2 left Earth in 2014 and reached its stationary position above the Ryugu asteroid in June 2018 after traveling 3.2 billion kilometers on an elliptical orbit around the sun for more than three years. It finally touched down on the asteroid twice the following year and collected its first-ever subsurface samples from an asteroid.

In December 2020, a capsule that had been carried on a six-year mission by Hayabusa 2 delivered more than 5.4 grams of surface material to Earth from the Ryugu asteroid 300 million kilometers away.

Launched in 2021 with a full-fledged investigation of the sample, the probe of Ryugu was conducted jointly by the JAXA and Japanese research institutions, including the University of Tokyo and Hiroshima University.

Aiming at unraveling the mysteries of the origin of the solar system and life, the probe suggested the presence of water and organic matter with previous analysis of the samples.

Kensei Kobayashi, professor emeritus of astrobiology at Yokohama National University, said the unprecedented discovery of multiple types of amino acids on an extraterrestrial body could even hint at the existence of life outside of Earth.

"Proving amino acids exist in the subsurface of asteroids increases the likelihood that the compounds arrived on Earth from space," he said.

Although it is still unknown how amino acids arrived on Earth in ancient times, one theory says they were brought by meteorites with amino acids being detected in a meteorite found on Earth while another possibility is that they were attached on the ground.

This time, Hayabusa 2 delivered the subsurface materials without them being exposed to the outside air after collecting the samples that had not been weathered by sunlight or cosmic rays, showing for the first time that amino acids exist on an asteroid in space.

来源: CGTN 日本共同社