New molecules found on a nearby asteroid can reveal the origin of life

New molecules found on a nearby asteroid can reveal the origin of life

In 2014, the Japan Aerospace Exploration Agency (JAXA) sent his Hayabusa2 spaceships to meet with 162173 Ryugu, a Near-Earth Asteroid (NEA) that periodically passes near Earth. In 2018, this test-return mission reached Ryugu and spent the next year and a half studying its surface and taking samples from its surface and below the surface. In 2020, these samples returned to Earth, where scientists began analyzing them in hopes of learning more about the early history of the solar system and answering key questions about the origin of life.

Earlier this year has first results of the analysis showed that Ryugu (as expected) is rich in carbon, organic molecules and volatiles (such as water) and suggested the possibility that it was once a comet. Based on a recent analysis, eight teams of Japanese researchers (including one from JAXA) recently announced that Ryugu carries strains of no less than 20 different amino acids – the building blocks of DNA and life itself! These findings could provide new insight into how life is distributed throughout the cosmos and may mean that it is more common than previously thought.

This study was launched in 2021 by JAXA and many Japanese research institutes, including the University of Tokyo and Hiroshima University. Originally, the analysis found evidence for 10 types of amino acids, but that number has since grown to 20. Since C-type asteroids are composed of materials left over from the formation of the solar system, the study of these ancient bodies can reveal things. about their early history. While samples of asteroids have been found on Earth that contained organic molecules, it is uncertain whether this was the result of contamination of the Earth’s biosphere.

One of Hayabusa2 The main objective of the mission was to determine whether there is a link between C-type asteroids and carbonaceous chondritic (CC) meteorites. This refers to meteorites that have been altered by water, which is indicated by the presence of clay minerals and salts inside them. For some time, scientists have suspected that these meteorites come from C-type asteroids that originate at the far end of the outer solar system. These asteroids, which are largely composed of volatile substances such as water ice, are believed to have introduced water into the inner solar system billions of years ago.

NASA took a sample from the Ryugu asteroid in June 2021.NASA

Regarding the Ryugu samples, researchers have been looking for an answer to a long-standing question: are C-type asteroids responsible for distributing water? and the building blocks of life in the entire solar system via CC meteorites? Per den Nebulosity hypotheses, the planets fused together approx. 4.5 billion years ago from a disk of gas and dust that settled around the newborn sun. One theory suggests that after The earth was collected from this disk, the planet’s surface was in a molten state that would have destroyed all amino acids. Gradually, meteorites reintroduced them to Earth after the surface cooled.

If this theory is correct, life arose on Earth thanks to organic material that does not originate here but was introduced by asteroids from the outer solar system (aka. Lithopanspermia). Hiroshi Naraoka, a planetary scientist at Kyushu University and the leader of the team, explained at Lunar and Planetary Science Conference in March:

“We detected various prebiotic organic compounds in the samples, including proteinogenic amino acids, polycyclic aromatic hydrocarbons similar to ground petroleum and various nitrogen compounds. These prebiotic organic molecules can spread throughout the solar system, potentially as interplanetary dust from the Ruygu surface through shocks or other” shocks. “

Hayabusa2 was groundbreaking in that it collected samples of subterranean materials that were not weathered by sunlight or cosmic rays. Kensei Kobayashi, Professor Emeritus of Astrobiology at Yokohama National University, also explained how these findings have significant implications for astrobiology. “Proving that amino acids are found in the lower surface of asteroids increases the likelihood that the compounds arrived on Earth from space,” he said, adding that this is a possible indication of how “life could have been born in more places in the universe than previously thought.” ”

Hayabusa2 is one of a handful of existing or proposed test-return missions dedicated to investigating the origin of life in the solar system. Between 2018 and 2021, NASA’S OSIRIS-REx also collected samples from NEA Bennu, which will be returned to Earth in September 2023. China also plans to launch its own sample return mission, known as Zhenghewhich will be launched in 2024 and meet with NEA Kamo’oalewa 2032.

This article originally appeared in Knowledgeable newspaper, an independent journalistic endeavor from Annual Reviews. sign up for newsletter.

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