The asteroid Bennu, sampled by NASA’s OSIRIS-REx mission, continues to yield surprising insights into the origins of life. Recent analyses of the returned material reveal not only the presence of amino acids – the building blocks of proteins – but also clues about how those amino acids formed, challenging long-held assumptions about the conditions necessary for life’s emergence. The findings, published in February 2026, suggest that these crucial molecules could have arisen in far more extreme environments than previously thought, specifically in icy, radiation-rich conditions rather than the warm, liquid water often considered essential.
The OSIRIS-REx mission successfully delivered approximately 122 grams of rock and dust from Bennu to Earth in . Since then, scientists have been meticulously analyzing the sample, uncovering a complex organic chemistry. Previous discoveries included all five nucleobases used in DNA and RNA, along with 14 of the 20 amino acids used to build proteins on Earth. The latest research adds to this growing list, identifying the amino acid tryptophan – a complex molecule essential for protein synthesis – and deepening the understanding of glycine formation.
Traditionally, the formation of amino acids in asteroids was thought to require liquid water. However, the new research, led by scientists at Penn State, points to a different pathway. By analyzing isotopes – slight variations in the mass of atoms – within the Bennu samples, the team discovered evidence that some amino acids likely formed in an icy-cold, radioactive environment present at the dawn of our solar system. “Our results flip the script on how we have typically thought amino acids formed in asteroids,” said Allison Baczynski, assistant research professor of geosciences at Penn State and co-lead author on the paper. “It now looks like You’ll see many conditions where these building blocks of life can form, not just when there’s warm liquid water. Our analysis showed that there’s much more diversity in the pathways and conditions in which these amino acids can be formed.”
This discovery is significant because it expands the range of potential locations where life’s building blocks could have originated. The early solar system was a chaotic place, with a variety of environments, including icy regions exposed to high levels of radiation. The presence of amino acids formed under these conditions suggests that the ingredients for life may be more widespread throughout the universe than previously imagined. The research doesn’t pinpoint a single origin story, but rather demonstrates the robustness of prebiotic chemistry – the chemical processes that could have led to the emergence of life.
Beyond amino acids, the Bennu samples have revealed other intriguing organic molecules. Researchers at Tohoku University in Japan identified sugars essential for biology, including ribose and, for the first time in an extraterrestrial sample, glucose. These sugars are key components of DNA and RNA, the molecules that carry genetic information. The detection of sugars, alongside amino acids and other organic compounds, reinforces the idea that the building blocks of life were prevalent throughout the early solar system. The samples also contain a gum-like substance not previously observed in astromaterials, and an unexpectedly high abundance of dust produced by supernova explosions.
The Bennu asteroid is a carbonaceous asteroid, meaning it’s rich in carbon. This composition makes it a time capsule, preserving materials from the early solar system with minimal alteration. The OSIRIS-REx mission specifically targeted Bennu because it is considered a relatively pristine relic from that era. The asteroid’s dark surface and carbon-rich composition indicated a high probability of containing organic molecules.
The implications of these findings extend beyond our understanding of Earth’s origins. They also inform the search for life elsewhere in the universe. If life’s building blocks can form in a variety of harsh environments, it increases the likelihood that life could exist on other planets or moons with conditions that were once considered uninhabitable. The discovery also highlights the importance of future missions to other asteroids and comets to further investigate the distribution of organic molecules in the solar system.
While the presence of these building blocks doesn’t equate to the presence of life itself, it provides crucial insights into the prebiotic chemistry that could have paved the way for life’s emergence. The ongoing analysis of the Bennu samples promises to continue reshaping our understanding of the origins of life, both on Earth and beyond. The research team emphasizes that the diversity of pathways for amino acid formation is a key takeaway, suggesting that the universe may be teeming with the potential for life, even in the most unexpected places.
