Asteroid Bennu Samples Reveal Rich supply of Amino Acids, Bolstering Theories on Life’s Origins
CAPE CANAVERAL, FL – November 29, 2025 – Initial analysis of samples returned from asteroid Bennu has revealed a significant abundance of organic compounds, including amino acids – the building blocks of proteins – offering compelling new evidence about the potential role asteroids played in seeding Earth with the ingredients for life. The findings, published today in Proceedings of the National Academy of Sciences, suggest Bennu underwent extensive aqueous alteration, a process involving water that facilitated the formation of these crucial molecules.
The finding marks a pivotal moment in astrobiology, potentially reshaping our understanding of how life arose on Earth. For decades, scientists have theorized that asteroids and comets delivered organic molecules to our planet during its early formation.The Bennu samples provide direct physical evidence supporting this hypothesis, demonstrating that carbon-rich asteroids can indeed harbor and preserve the essential components for life. This research impacts fields ranging from planetary science and chemistry to biology and the search for extraterrestrial life, and future studies of the samples promise even deeper insights into the prebiotic chemistry of the early solar system.
Researchers, led by Angel Mojarro, analyzed samples collected by NASA’s OSIRIS-REx spacecraft, which returned to Earth in September 2023 after a seven-year journey to Bennu. The analysis revealed a diverse suite of prebiotic organic compounds, indicating that the asteroid experienced prolonged interaction with liquid water. This aqueous alteration is believed to have created an environment conducive to the formation of amino acids and other complex organic molecules.
“These findings suggest that Bennu represents a time capsule of the early solar system, preserving materials from a period when Earth was still forming,” explained Mojarro. “The presence of amino acids, especially in this context, is incredibly exciting.”
Bennu, a carbonaceous asteroid approximately 500 meters in diameter, is considered a relic from the early solar system, dating back to its formation roughly 4.5 billion years ago. The OSIRIS-REx mission aimed to collect and return a sample from Bennu to Earth for detailed laboratory analysis, providing scientists with an unprecedented opportunity to study pristine asteroid material.
The research team utilized advanced analytical techniques to identify and quantify the organic compounds within the Bennu samples. Their findings indicate that the asteroid’s composition is heterogeneous, with variations in organic content across different regions. this suggests that the aqueous alteration process was not uniform throughout the asteroid, leading to localized concentrations of prebiotic molecules.
Further analysis of the Bennu samples is ongoing, with scientists planning to investigate the chirality (handedness) of the amino acids and search for other complex organic molecules. These investigations could provide further clues about the origin of life on Earth and the potential for life elsewhere in the universe.
© 2025 Science X Network. DOI: 10.1073/pnas.2512461122.
