NASA’s OSIRIS-REx Mission Reveals Asteroid Bennu’s Potential for Life
In a groundbreaking discovery, NASA’s OSIRIS-REx mission has returned samples from asteroid Bennu, revealing chemical building blocks that could shed light on the origins of life. Jason Dworkin, the project scientist for OSIRIS-REx at NASA’s Goddard Space Flight Center, presented a vial containing part of the Bennu sample in a recent video frame. These materials, delivered to Earth in 2023, offer insights into the conditions that may have been crucial for life to form on Earth—and potentially on other planets and moons across the solar system.
While these samples don’t provide direct evidence of life, they do show that the ingredients necessary for life were likely widespread throughout the early solar system, suggesting that the emergence of life could have been possible on distant worlds.
As Nicky Fox, Associate Administrator for NASA’s Science Mission Directorate, puts it, “OSIRIS-REx is rewriting the textbook on the origins of our solar system. Asteroids like Bennu offer a glimpse into our planet’s early history and the raw materials that may have set the stage for life on Earth.”
The findings were published in two prominent scientific journals, Nature and Nature Astronomy. They describe the first detailed analyses of Bennu’s rocks and dust, offering an unprecedented look at the chemical composition of materials from beyond our planet.
Molecules of Life Found on Bennu
Among the most significant discoveries were the identification of 14 amino acids, which are the building blocks of proteins essential to life on Earth. Scientists also found all five nucleobases that form the foundation of DNA and RNA, molecules responsible for storing and transmitting genetic information. The presence of these molecules in the Bennu samples is important because they are critical to life’s processes on Earth.
Ammonia, which can play a key role in forming complex organic compounds, was also detected in the Bennu samples. Combined with formaldehyde, ammonia can produce amino acids—a crucial step in the formation of proteins, which power the biological functions of life.
This discovery of life’s basic building blocks in the pristine Bennu sample is exciting because it supports the theory that distant, cold objects like asteroids may have been key sources of these essential ingredients throughout the solar system.
Evidence of an Ancient Environment
In addition to finding life-related molecules, the team led by Tim McCoy at the Smithsonian’s National Museum of Natural History discovered evidence of an ancient environment on Bennu that could have been conducive to the chemical processes needed for life. The team identified traces of 11 minerals in the samples, many of which form when water evaporates, leaving behind salts. These minerals are similar to those found on other worlds, like Saturn’s moon Enceladus, suggesting that Bennu might have once hosted a salty, watery environment.
The discovery of these evaporates is significant because it points to a long-term, stable environment that could have provided the right conditions for chemical reactions to take place, potentially leading to life. Some minerals, like trona, were even identified for the first time in extraterrestrial samples.
The Mystery of Left-Handed Amino Acids
However, the findings also raise intriguing questions. On Earth, life exclusively uses left-handed amino acids to build proteins, but the Bennu samples contain a mixture of both left- and right-handed versions. This suggests that early Earth may have started with a similar mixture, but scientists are still puzzled about why life “chose” left-handed amino acids over their right-handed counterparts.
As Jason Dworkin explains, "OSIRIS-REx has provided a treasure trove of data, helping us paint a picture of a solar system rich with the potential for life. The real mystery is why we haven’t found life elsewhere—yet."
Conclusion
The OSIRIS-REx mission has already provided new insights into the early solar system, and these latest findings are adding important pieces to the puzzle of how life may have arisen on Earth. With more research to come, scientists continue to explore the potential for life in our solar system—and beyond.
NASA’s OSIRIS-REx mission was a collaboration involving NASA Goddard, the University of Arizona, Lockheed Martin, and various international partners, including the Canadian Space Agency (CSA) and Japan’s JAXA. The mission's success has been a crucial step in understanding the broader story of life's potential across the universe.
For more information on the OSIRIS-REx mission, visit: