Asteroid Bennu Yields Key Building Blocks of Life, Bolstering Theories of Extraterrestrial Origins
Samples collected from the asteroid Bennu by NASA’s OSIRIS-REx mission contain a diverse array of amino acids and components crucial to DNA, potentially strengthening the hypothesis that life on Earth originated in space. The findings, revealed on February 9, 2026, offer a new perspective on the chemical origins of life and the role asteroids may have played in seeding our planet.
The analysis of rocks and dust retrieved from Bennu, a carbonaceous asteroid approximately 200 million miles from Earth, revealed over 33 different amino acids. Notably, 14 of these amino acids are used in protein synthesis, even as the remaining 19 are rare or previously unknown. This discovery builds on previous findings of organic molecules in meteorites, but the Bennu samples offer a significant advantage: they haven’t been subjected to the heat of atmospheric entry or terrestrial contamination. As NASA scientists explained, the samples are “very pristine.”
Further analysis showed the presence of all five nucleobases – adenine, guanine, cytosine, thymine, and uracil – which form the building blocks of DNA and RNA. The samples were also rich in nitrogen and ammonia. These findings were published in the journal Nature Astronomy on January 30, 2025, by an international research team involving NASA’s Goddard Space Flight Center.
Bennu is estimated to have formed around 4.5 billion years ago, around the same time as our solar system. Unlike planets like Earth, which have undergone significant geological and atmospheric changes, smaller asteroids like Bennu have remained relatively unchanged, preserving a snapshot of the early solar system’s chemical composition. This makes Bennu a kind of “frozen time capsule,” according to researchers. The asteroid is also classified as a “near-Earth object,” meaning it has the potential to come close to our planet.
The discovery of ribose, a crucial component of RNA, within the Bennu samples further supports the theory of extraterrestrial delivery of organic molecules to early Earth. Scientists have long debated whether life arose spontaneously on Earth (“abiogenesis”) or if the necessary ingredients were delivered from elsewhere. This latest research lends increasing weight to the “panspermia” hypothesis – the idea that life exists throughout the universe and is distributed by asteroids, meteoroids, and other celestial bodies. The findings highlight the potential for asteroids to have acted as delivery vehicles for the building blocks of life, even in the harsh conditions of early Earth, which was a hot and barren landscape approximately 4 billion years ago.
The OSIRIS-REx mission successfully collected samples from Bennu in 2020, and the spacecraft returned to Earth in 2023. Ongoing analysis of the samples promises to reveal even more insights into the origins of life and the composition of the early solar system. This research underscores the importance of continued space exploration in unraveling the mysteries of our universe and our own existence.
