NASA’s OSIRIS-REx mission recently unraveled the complex history of the asteroid Bennu, linking it to the building blocks necessary for life. The findings, revealed after the mission’s samples returned to Earth, suggest asteroids like Bennu could have played a pivotal role as cosmic messengers, potentially seeding planets with the ingredients necessary for life.
Bennu, approximately 320 million kilometers from Earth, was targeted by OSIRIS-REx for its carbon-rich properties. Launched to explore and analyze this near-Earth asteroid, the spacecraft successfully collected around 122 grams of dust and small rocks from Bennu’s surface, landing the capsule safely back on Earth in September 2023.
According to Tim McCoy of the Smithsonian Institution, “That’s the kind of environment could have been essencial to the steps for life.” Organic material retrieved from Bennu includes amino acids and nucleobases—essential elements of DNA and RNA—indicating the presence of life-supporting conditions.
Scientists were astounded by the variety of organic compounds found within the samples. Dante Lauretta from the University of Arizona noted, “What we found exceeded expectations.” Among the findings were 14 of the 20 amino acids found on Earth, all five of the necessary nucleobases, as well as ammonia and nitrogen—key components for life.
The samples also contained evidence of sodium-rich minerals, reminiscent of salty environments similar to those on Earth’s lakebeds. These minerals suggest Bennu’s parent body harbored liquid water, shedding new light on the asteroid's potentially life-supporting chemistry.
“The clues we’re searching for are minuscule and easily destroyed,” remarked Danny Glavin, NASA Senior Sample Scientist, emphasizing the importance of the pristine condition of the Bennu samples. These findings align with previous theories positing asteroids as delivery systems for organic molecules throughout the solar system.
Despite the lack of evidence for direct life, Nicky Fox from NASA stated, “We’re likely seeing the beginnings of biochemistry on Bennu.” This notion opens the door to exciting possibilities of life existing elsewhere, as these minerological features are similar to those found on other celestial bodies, such as Ceres and Enceladus.
With the rich geological background presented by Bennu, future investigations are warranted. The continued analyses of the asteroid’s samples will likely provide more insight, as scientists endeavor to understand how these primordial ingredients came together to contribute to life on Earth.
“Are we alone?” McCoy queries, raising fundamental questions about humanity’s origins. The discoveries made through the OSIRIS-REx mission extend not only to our planet’s history but also suggest significant attention must be directed toward other distant worlds within our solar system.
Future missions targeting similar phenomena—such as planned sample-return missions from Ceres and studies of Europa and Enceladus—will undoubtedly advance our grasp of how life began and evolved. With each sample returned and analyzed, astronomers hope to bring humanity one step closer to unraveling the mysteries of our existence among the stars.