Building Blocks of Life Found on Samples Collected From an Asteroid

The find suggests that amino acids could land on Earth on meteorites

An image of the asteroid 162173 Ryugu  as it appears in space. The asteroid looks like a grey diamond shaped chunk.
The carbon-rich asteroid is of interest to researchers because the chunk of rock has remained unchanged since the formation of the solar system 4.5 billion years ago. ISAS/JAXA Hayabusa2 via Wikicommons under CC BY 4.0

Researchers say they have found more than ten types of amino acids, the building blocks of proteins, in samples collected from a diamond-shaped asteroid 200 million miles from Earth. The detection is the first time amino acids have been found to exist on asteroids in space and may have implications in understanding how organic molecules arrived on Earth, reports the Japan Times. The findings were presented at the Lunar and Planetary Conference in March 2022. 

The molecules were found in samples from the asteroid dubbed 162173 Ryugu. The Japan Aerospace Exploration Agency's (JAXA) Hayabusa2 asteroid explorer collected about 5.4 grams of gritty, ashy particles from the space rock's surface and returned them to Earth on December 6, 2020. A previous study looked at the mineral and chemical composition of samples taken from Ryugu on the same mission by Hayabusa2. This study is the first to go looking for amino acids in these samples.

The carbon-rich asteroid is of interest to researchers because it has remained unchanged since the formation of the solar system 4.5 billion years ago. Ryugu age, surface and rock composition can give researchers a look at the early period in time, reports Gizmodo's Isaac Schultz.

Amino acids are the building blocks of life because they string together to form proteins, which carry out most chemical processes in cellular life. The new find suggests that amino acids may have been delivered to Earth on asteroids like Ryugu, reports Stephen Luntz for IFL Science. Previous research supports this idea because molecules on Ryugu were also found on meteorites that landed on Earth 3.3-billion years ago, Gizmodo reports. However, since asteroids on Earth have interacted with life, climate and tectonic processes, researchers couldn’t say whether amino acids on material from space came from space or were contamination. Finding amino acids on Ryugu connects meteorites on Earth with amino acids in space. "Proving amino acids exist in the subsurface of asteroids increases the likelihood that the compounds arrived on Earth from space," Kensei Kobayashi, an astrobiologist at Yokohama National University, says to Kyodo News. 'It also means amino acids can likely be found on other planets and natural satellites, hinting that "life could have been born in more places in the universe than previously thought."

As researchers continue to analyze Ryugu's samples, more information about how the asteroid formed and its composition will come to light.

After Hayabusa2 dropped off the Ryugu samples, researchers sent the probe to embark on more missions to study asteroids. The space probe will fly by asteroid 2001 CC21—a near-Earth rock about the size of the Golden Gate Bridge—in 2026 and by asteroid 1998 KY26—a smaller mass about the size of a school bus—in 2031, according to the Planetary Society.