NASA’s OSIRIS-REx mission has taken a giant leap for the sciences by delivering remarkable samples from the carbon-rich asteroid Bennu, offering insights related to the origins of life on Earth. Returned to Earth in late 2023, these samples have sparked excitement within the scientific community, as researchers analyze the potential for life beyond our planet.
According to findings published on January 29, 2025, by NASA and the Smithsonian, the asteroid Bennu contains all five of the nucleobases necessary for constructing DNA and RNA, as well as 14 of the 20 amino acids found on Earth. These molecules serve as the building blocks of life, which raises tantalizing questions about the conditions under which life might emerge.
Bennu, which travels close to Earth every six years, is believed to have originated from larger bodies located farther from the Sun. Its composition provides significant evidence for the notion of widespread conditions conducive to life throughout the early solar system.
Researchers report finding extraordinarily high amounts of ammonia and formaldehyde within the samples. Ammonia is pivotal to organic chemistry, as it can react with other compounds such as formaldehyde to form amino acids and other necessary molecules. This reaction is central to the biochemical processes seen on Earth.
Interestingly, the amino acids on Bennu exhibit chirality—a mirror-image structural property. While life on Earth predominantly uses left-handed amino acids, Bennu’s samples exhibit nearly equal proportions of both left- and right-handed varieties. Jason Dworkin, OSIRIS-REx project scientist at NASA, commented, “Data from OSIRIS-REx adds major brushstrokes to a picture of a solar system teeming with the potential for life.”
The discoveries also indicate the presence of liquid saline brines, hinting at Bennu's previously hospitable environment. Tim McCoy, curator of meteorites at the Smithsonian, led investigations identifying 11 evaporite minerals, which are typically formed through the evaporation of salt-laden water, leaving crystalline residues. “These papers really go hand in hand in trying to explain how life’s ingredients actually came together to make what we see on this aqueously altered asteroid,” stated McCoy, emphasizing the significance of their findings.
This newfound evidence suggests not only could Bennu have previously harbored the necessary conditions for life, but it also points toward the idea of our early solar system being replete with environments ripe for life’s emergence. Nicky Fox, associate administrator of NASA’s Science Mission Directorate, remarked, “Asteroids provide a time capsule of our home planet’s history, and Bennu’s samples are pivotal to our knowledge of what ingredients existed before life began on Earth.”
The monumental OSIRIS-REx mission stands as NASA’s “first” successful return of samples from an asteroid. With 121.6 grams of material retrieved, scientists are now poised to explore and analyze the makeup of asteroids to gain more insights about the broader cosmic narrative of life.
While these findings send ripples of excitement through the scientific community, they also beckon more questions. Why did life fail to emerge on Bennu, even though it harbored the necessary building blocks? Researchers suspect the harsh environmental conditions, such as extreme radiation and low temperatures, made it impossible for life to take root.
The questions don’t stop there—researchers are exploring how similar findings from other celestial bodies, like ocean moons such as Europa and Enceladus, may yield clues about life beyond Earth. If early Earth was influenced by materials from icy asteroids like Bennu, it piques curiosity about the possibility of life elsewhere where conditions may have been, and still could be, suitable for life.
Scientists continue to study how these amino acids and nucleotide bases interact with each other and how they might inform our comprehension of prebiotic chemistry—the processes leading to life. With the current findings from Bennu, the narrative expands to include the potential for various types of life existing elsewhere based on complex organic compounds discovered amid the cosmic dust.
Each new insight gained from this analysis brings scientists another step closer to unraveling the origins of life within the cosmos. The excitement of future discoveries remains palpable as we ponder the remaining questions—especially why Earth is so unique when compared with other celestial bodies brimming with necessary ingredients yet devoid of life.
The research surrounding the OSIRIS-REx mission is just the start. After all, with each facet unraveled from Bennu, we edge nearer to perhaps answering one of humanity’s most persistent questions: Are we alone in the universe? The findings spark enthusiasm for future missions and explorations, providing even more opportunities to understand our universe’s rich, complex intricacies.