Asteroid Bennu isn’t just another space rock drifting through the cosmos—it’s a relic from the early days of our Solar System. Scientists believe that this 500-meter-wide asteroid holds crucial clues about the origins of life on Earth and possibly beyond.
The OSIRIS-REx Mission
Artist’s conception of the OSIRIS-REx spacecraft at Bennu asteroid. NASA/GSFC, Public domain, via Wikimedia Commons
In 2016, NASA launched the OSIRIS-REx spacecraft on a daring mission to Bennu. After orbiting the asteroid for nearly two years, the spacecraft successfully collected samples in 2020 before returning them to Earth in 2023. The mission was a technological marvel, proving humanity’s ability to reach into deep space and bring back fragments of our cosmic past.
Why Bennu?
On Dec. 19, 2019, OSIRIS-REx used its NavCam 1 camera to capture this image of three familiar planetary bodies: asteroid Bennu, Earth, and the moon. Despite the spacecraft’s distance from home – about 71 million miles (114 million kilometers) – Earth and the Moon are visible in the lower left due to the long exposure time used for this image (five seconds). The spacecraft’s range to Bennu is only about 27 miles (43 kilometers), so the asteroid appears highly overexposed in the upper right. The head of the constellation Hydra is also visible in the lower right portion of the image. NavCam 1 is a black-and-white imager that is one of three cameras comprising TAGCAMS (the Touch-and-Go Camera System), which is part of OSIRIS-REx’s guidance, navigation, and control system. NASA/Goddard/University of Arizona/Lockheed Martin Space, Public domain, via Wikimedia Commons
NASA chose Bennu for several compelling reasons. Its carbon-rich composition makes it an ideal candidate for studying the early building blocks of life. Additionally, Bennu’s relatively close proximity to Earth and its well-documented orbital path made it a feasible target for the OSIRIS-REx mission. Scientists also believe that Bennu has remained largely unchanged since the Solar System’s formation, making it a pristine time capsule that can provide invaluable insights into our cosmic history.
A Treasure Trove of Organic Compounds
A top-down view of one of the containers holding rocks and dust from asteroid Bennu, with hardware scale marked in centimeters. NASA Johnson Space Center / Erika Blumenfeld & Joseph Aebersold, Public domain, via Wikimedia Commons
When scientists cracked open the sample container, they found something astonishing—thousands of organic molecules, including amino acids and nucleobases, the essential components of DNA and RNA. This discovery reinforces the theory that asteroids may have seeded Earth with the ingredients necessary for life billions of years ago.
Water Once Flowed on Bennu
The features on Asteroid Bennu have been given official names. Bennu’s own name was inspired by an ancient Egyptian deity, depicted as a bird, that was associated with the Sun, creation and rebirth. In keeping with this theme, the features have been given names related to mythological birds and bird-like creatures. NASA/OSIRIS-REx, CC BY 4.0, via Wikimedia Commons
The sample analysis didn’t just reveal organic compounds; it also showed signs of water. Scientists found minerals and salts indicative of past liquid water, suggesting that Bennu’s parent body once had a wet and possibly habitable environment. This finding raises intriguing questions about the role of asteroids in delivering water to planets across the Solar System.
Bennu’s Role in the Search for Alien Life
Oblique view of the Touch-And-Go (TAG) sample site with pre-post surface height change data represented by both a color map and by offsetting the original digital terrain model (DTM) to reveal the TAG crater. The DTM offset is only applied to the surface region within ~7.5 metres of impact. NASA’s Scientific Visualization Studio – USRA/Kel Elkins, KBR Wyle Services, LLC/Dan Gallagher, The University of Arizona/Dante Lauretta, JHUAPL/Olivier Barnouin, Public domain, via Wikimedia Commons
Could the same molecules that kickstarted life on Earth be scattered across the universe? The discovery of these building blocks on Bennu hints at the possibility that similar processes might have occurred on other planets and moons. If asteroids like Bennu carried these compounds across the Solar System, the odds of life elsewhere just skyrocketed.
A Hazard and an Opportunity
This trio of images acquired by NASA’s OSIRIS-REx spacecraft shows a wide shot and two close-ups of a region in asteroid Bennu’s northern hemisphere. The wide-angle image (left), obtained by the spacecraft’s MapCam camera, shows a 590-foot (180-meter) wide area with many rocks, including some large boulders, and a “pond” of regolith that is mostly devoid of large rocks. The two closer images, obtained by the high-resolution PolyCam camera, show details of areas in the MapCam image, specifically a 50-foot (15 meter) boulder (top) and the regolith pond (bottom). The PolyCam frames are 101 feet (31 meters) across and the boulder depicted is approximately the same size as a humpback whale. The images were taken on February 25 while the spacecraft was in orbit around Bennu, approximately 1.1 miles (1.8 km) from the asteroid’s surface. The observation plan for this day provided for one MapCam and two PolyCam images every 10 minutes, allowing for this combination of context and detail of Bennu’s surface. NASA/Goddard/University of Arizona, Public domain, через Викисклад
Bennu isn’t just scientifically fascinating—it’s also classified as a potentially hazardous asteroid. With a small but significant chance of colliding with Earth in 2182, Bennu remains an object of intense study. Understanding its composition could help scientists develop strategies to prevent future asteroid impacts.
A Glimpse Into the Future
This image was taken from the surface of Bennu by the OSIRIS-REx spacecraft just after it landed on the asteroid. Taken from the “Nightingale” landing site on asteroid Bennu 56°N 43°E. (20 October 2020). NASA/Goddard/University of Arizona, Public domain, via Wikimedia Commons
The samples collected from Bennu will fuel decades of research, helping scientists unravel the mysteries of the early Solar System. With upcoming missions to other asteroids and icy moons, humanity is on the brink of discovering whether we are truly alone in the universe.
The Final Word
Pictured here following the field recovery rehearsal is the entire OSIRIS-REx mission recovery and curation team, consisting of members from NASA’s Goddard Space Flight Center, NASA’s Johnson Space Center, the University of Arizona and Lockheed Martin. Credit: Dusty Volkel/Lockheed Martin Space. NASA’s Scientific Visualization Studio – Dusty Volkel, Dan Gallagher, Lauren Duda, Ned Barbee, Lauren Duda, Rani Gran, Public domain, via Wikimedia Commons
Bennu is more than just a floating pile of rubble—it’s a cosmic time capsule, carrying secrets of our past and clues to our future. As scientists continue to analyze its samples, we inch closer to answering one of the biggest questions in existence: How did life begin, and where else might it exist?
Jan loves Wildlife and Animals and is one of the founders of Animals Around The Globe. He holds an MSc in Finance & Economics and is a passionate PADI Open Water Diver. His favorite animals are Mountain Gorillas, Tigers, and Great White Sharks. He lived in South Africa, Germany, the USA, Ireland, Italy, China, and Australia. Before AATG, Jan worked for Google, Axel Springer, BMW and others.
