We knew when Japan’s Hayabusa2 spacecraft arrived at the asteroid, Ryugu, 4 years ago - after a journey of nearly 2 billion miles (3.2bn km) - there’d be some amazing findings forthcoming. That arrived with a paper published a week ago Friday , which supported a theory that a class of solar-system rocks (called asteroids) impacting on Earth helped jump-start primordial life-forms. The amazing aspect is that a sample (5.4 grams) was actually recovered from the asteroid and sent back to Earth to be deposited in the Australian Outback in December, 2020.
The paper - published in The Proceedings of the Japan Academy- described the initial analyses of the asteroid dust and pebbles - materials - the first significant-sized samples from an asteroid after an earlier Japanese probe collected only tiny grains The sequence of the collection process in the recent mission is depicted in the graphic above - below the image of Ryugu.
The objective of the Hayabusa-2 sample return mission was to visit and explore the C-type asteroid 1999 JU3(aka 'Ryugu'), a space body of about 920 m in length and of particular interest to researchers, because it consists of 4.5 billion-year-old material that has been altered very little. As I noted in a December, 2019 post C-type asteroids are expected to contain organic and hydrated minerals.
In the case of Ryugu we have a 'bonus' in the form of amino acids found in the collected materials. (Amino acids are the building blocks of proteins, which are used by living things to speed up chemical reactions and build more complex structures.) There was no danger of terrestrial contamination of the sample given the materials were directly extracted from Ryugu and brought back untouched to Earth. As the paper points out:
"This is proof that Ryugu and thus other extraterrestrial materials can provide organic molecules essential for the origin of life on Earth.”
The finding definitely secures support for an earlier theory of panspermia - proposed by some astronomers (e.g, Chandra Wickramasinghe, Sir Fred Hoyle) that life on Earth was incepted from an outside or extraterrestrial impact. This as opposed to the usually accepted theory of abiogenesis, e.g.
In the words of researcher Hisamitsu Awaki of Ehime University, quoted in a WSJ (June 10) account: "I think this will be a catalyst to push ahead in a big way with research into extraterrestrial origins.”
A separate group led by scientists at Hokkaido University and elsewhere also analyzed samples from Ryugu and the results of their analysis were described in a paper published by the journal Science. The Science paper said the Ryugu samples “are more chemically pristine than other solar-system materials analyzed in laboratories,” including meteorites. In the lowest image above one of the Hokkaido research exploration team is shown retrieving the asteroid sample from the Australian Outback in 2020.
The biggest surprise from their analysis is that the bits recovered are a close match to a 1.5-pound meteorite that landed in Tanzania in 1938. The Ivuna meteorite, named after the region it fell in, was of a very rare type. known as a C.I. chondrite.
Both groups concluded that Ryugu samples represented a snapshot of what the solar system was like in its earliest days after it first coalesced from a cloud of gas and dust 4.6 billion years ago. They said the asteroid formed a few million years after the origin of the solar system.
More samples from extraterrestrial bodies are likely
to reach Earth this decade. The National Aeronautics and Space
Administration’s Osiris-Rex mission is set to return a sample of
at least 2.1 ounces from the asteroid Bennu to Earth next year. Japan is
planning a 2024 launch for a mission to the moons of Mars that
aims to bring back material from the Martian moon Phobos by around 2029.
We look forward to these further exciting missions and the potential scientific discoveries they promise. However, don't expect the issue of origin of life on Earth to be settled anytime soon. More likely a 'hybrid' theory or hypothesis will emerge to try to explain facets one proposal alone can't accommodate.
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