Asteroid Bennu Sample Unlocks Secrets of Water and Organic Chemistry in the Early Solar System
A team of US astronomers has carried out one of the deepest analyses to date of a sample from the asteroid Bennu, revealing new details about how water and organic material interacted during the earliest stages of the solar system.
Scientists have completed one of the most detailed analyses ever conducted on a sample from the asteroid Bennu, shedding new light on how water and organic material interacted during the solar system's earliest days.
The study, led by a team of US astronomers, examined material returned to Earth by NASA's OSIRIS-REx spacecraft, which successfully delivered its precious cargo in September 2023 after a years-long journey to the near-Earth asteroid and back.
Researchers found compelling evidence that liquid water once flowed through the porous rocky body of Bennu when the asteroid was still in its formative stages, billions of years ago. The findings suggest that water played a far more dynamic and transformative role in shaping primitive asteroids than previously understood.
The interaction between water and minerals inside Bennu appears to have created conditions that allowed complex organic molecules to form and persist. This has significant implications for theories about how life's chemical building blocks may have been distributed across the early solar system.
Mineralogical analysis of the sample revealed hydrated silicates and carbonate minerals, both of which are strong indicators of aqueous alteration — a process in which liquid water chemically reacts with rock over extended periods. The presence of these minerals points to a wet history that predates the formation of the planets themselves.
The team noted that Bennu likely originated from a much larger parent body that was rich in water ice. As that body warmed — possibly due to radioactive decay — the ice melted, allowing water to percolate through cracks and pores in the rock before the asteroid eventually broke apart and reformed into what we know as Bennu today.
These findings add to a growing body of evidence suggesting that carbon-rich asteroids like Bennu may have delivered both water and organic compounds to the early Earth, potentially playing a crucial role in setting the stage for life. Further analysis of the Bennu sample is expected to yield additional discoveries in the coming years.