Asteroid discovery suggests ingredients for life on Earth came from
space
Send a link to a friend
[March 22, 2023]
By Will Dunham
(Reuters) - Two organic compounds essential for living organisms have
been found in samples retrieved from the asteroid Ryugu, buttressing the
notion that some ingredients crucial for the advent of life arrived on
Earth aboard rocks from space billions of years ago.
Scientists said on Tuesday they detected uracil and niacin in rocks
obtained by the Japanese Space Agency's Hayabusa2 spacecraft from two
sites on Ryugu in 2019. Uracil is one of the chemical building blocks
for RNA, a molecule carrying directions for building and operating
living organisms. Niacin, also called Vitamin B3 or nicotinic acid, is
vital for their metabolism.
The Ryugu samples, which looked like dark-gray rubble, were transported
155 million miles (250 million km) back to Earth and returned to our
planet's surface in a sealed capsule that landed in 2020 in Australia's
remote outback for analysis in Japan.
Scientists long have pondered about the conditions necessary for life to
arise after Earth formed about 4.5 billion years ago. The new findings
fit well with the hypothesis that bodies like comets, asteroids and
meteorites that bombarded early Earth seeded the young planet with
compounds that helped pave the way for the first microbes.
Scientists previously detected key organic molecules in carbon-rich
meteorites found on Earth. But there was the question of whether these
space rocks had been contaminated by exposure to the Earth's environment
after landing.
![](http://archives.lincolndailynews.com/2023/Mar/22/images/ads/current/llm_lda_ANIMAL_2023.png)
"Our key finding is that uracil and niacin, both of which are of
biological significance, are indeed present in extraterrestrial
environments and they may have been provided to the early Earth as a
component of asteroids and meteorites. We suspect they had a role in
prebiotic evolution on Earth and possibly for the emergence of first
life," said astrochemist Yasuhiro Oba of Hokkaido University in Japan,
lead author of the research published in the journal Nature
Communications.
"These molecules on Ryugu were recovered in a pristine extraterrestrial
setting," Oba said. "It was directly sampled on the asteroid Ryugu and
returned to Earth, and finally to laboratories without any contact with
terrestrial contaminants."
[to top of second column]
|
![](../images/032223PIX/news_i19.gif)
The carbonaceous asteroid Ryugu is seen
from a distance of about 12 miles (20 km) during the Japanese Space
Agency's Hayabusa2 mission on June 30, 2018. JAXA, University of
Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba
Institute of Technology, Meiji University, University of Aizu and
AIST/Handout via REUTERS
![](http://archives.lincolndailynews.com/2023/Mar/22/images/ads/current/debbies_lda_032222.png)
RNA, short for ribonucleic acid, would not be possible without
uracil. RNA, a molecule present in all living cells, is vital in
coding, regulation and activity of genes. RNA has structural
similarities to DNA, a molecule that carries an organism's genetic
blueprint.
Niacin is important in underpinning metabolism and can help produce
the "energy" that powers living organisms.
The researchers extracted uracil, niacin and some other organic
compounds in the Ryugu samples by soaking the material in hot water
and then performing analyses called liquid chromatography and
high-resolution mass spectrometry.
Organic astrochemist and study co-author Yoshinori Takano of the
Japan Agency for Marine-Earth Science and Technology (JAMSTEC) said
he is now looking forward to the results of analyses on samples
being returned to Earth in September from another asteroid. The U.S.
space agency NASA during its OSIRIS-REx mission collected samples in
2020 from the asteroid Bennu.
Oba said uracil and niacin were found at both landing sites on Ryugu,
which is about a half-mile (900 meters) in diameter and is
classified as a near-Earth asteroid. The concentrations of the
compounds were higher at one of the sites than the other.
The sample from the site with the lower concentrations was derived
from surface material more susceptible to degradation induced by
energetic particles darting through space, Oba said. The sample from
the other site was mainly derived from subsurface material more
protected from degradation, Oba added.
Asteroids are rocky primordial bodies that formed in the early solar
system. The researchers suggest that the organic compounds found on
Ryugu may have been formed with the help of chemical reactions
caused by starlight in icy materials residing in interstellar space.
(Reporting by Will Dunham in Washington; Editing by Rosalba O'Brien)
[© 2023 Thomson Reuters. All rights
reserved.]This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content. |