Minerals crucial to life found in asteroid samples from space
Samples brought back to Earth from asteroid “Bennu” in 2023 have been found to contain crucial building blocks for life—including amino acids and all five DNA and RNA nucleobases.
The findings, published in two papers in Nature and Nature Astronomy, also revealed that evaporated water once left behind a briny broth, where salts and minerals provided an environment for life’s basic elements to interact and form more complex structures.
Some of the mineral compounds found have never been observed in extraterrestrial materials before.
NASA/Goddard/University of Arizona
Why It Matters
The presence of brine-like environments and organic compounds on Bennu suggests that conditions necessary for the formation of organic compounds existed beyond Earth.
This supports theories that asteroids may have delivered the essential ingredients for life to our planet billions of years ago.
What to Know
Bennu, a carbon-rich asteroid formed as part of a parent body approximately 4.5 billion years ago, has long intrigued researchers due to its potential to harbor traces of water and organic molecules.
NASA’s OSIRIS-REx mission, launched in 2016, successfully collected 120 grams of samples from Bennu in 2020 and delivered them to Earth in September 2023.
Scientists have since been analyzing these samples to uncover their chemical composition.
One of the most surprising discoveries was the presence of sodium carbonate compounds, known as soda ash or trona, which have never been identified in previous asteroid or meteorite samples.
These minerals suggest that Bennu’s parent body, from which is formed, once had water-rich environments that evaporated, leaving brines resembling salty lakebeds here on Earth.
Rob Wardell, Tim Gooding and Tim McCoy, Smithsonian
Meanwhile, the Nature Astronomy study revealed that samples from the asteroid Bennu contain a vast array of organic molecules. Among them were 14 of the 20 amino acids used to build proteins in Earth’s life forms, as well as 19 non-protein amino acids that are uncommon or entirely absent in known biology.
the researchers also detected all five fundamental nucleobases—adenine, guanine, cytosine, thymine and uracil—crucial components of DNA and RNA.
What People Are Saying
Tim McCoy, curator of meteorites at the Smithsonian and co-lead author of the Nature study, said in a statement: “We now know from Bennu that the raw ingredients of life were combining in really interesting and complex ways on Bennu’s parent body. We have discovered that next step on a pathway to life.”
Sara Russell, a cosmic mineralogist at the Natural History Museum in London and another co-lead author, added: “It’s been an absolute joy to be involved in this amazing mission, and to collaborate with scientists from around the world to attempt to answer one of the biggest questions asked by humanity: how did life begin? Together we have made huge progress in understanding how asteroids like Bennu evolved, and how they may have helped make the Earth habitable.”
NASA
What Happens Next
The new findings set the stage for further research on how extraterrestrial environments might foster prebiotic chemistry.
“We found something we didn’t expect, and that’s the best reward for any kind of exploration,” McCoy said.
“We now know we have the basic building blocks to move along this pathway towards life, but we don’t know how far along that pathway this environment could allow things to progress.”
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