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An ancient relic of our solar system’s early days, Bennu has seen more than 4.5 billion years of history. Scientists think that within 10 million years of our solar system’s formation, Bennu’s present-day composition was already established.
Bennu likely broke off from a much larger carbon-rich asteroid about 700 million to 2 billion years ago. It likely formed in the Main Asteroid Belt between Mars and Jupiter, and has drifted much closer to Earth since then. Because its materials are so old, Bennu may contain organic molecules similar to those that could have been involved with the start of life on Earth.
Go farther. Explore Bennu In Depth ›
Ten Things to Know About 101995 Bennu
The asteroid was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey on September 11, 1999. Bennu’s original designation was 1999 RQ36. In 2013, a third-grade student named Michael Puzio won a contest to name the asteroid. Bennu has drifted into near-Earth space because of gravitational interactions with giant planets and the gentle push of heating from the Sun. Bennu's density is only about 30 percent more than water. This suggests the asteroid is probably a loose collection of rocks, like a pile of rubble. Bennu has a close approach to Earth every six years. Scientists estimate Bennu has a 1‐in‐2,700 chance of impacting the Earth during one of its close approaches to the Earth in the late 22nd century. Bennu may burn up in the Sun. Over millions of years, of all of the planets, Bennu is most likely to hit Venus The boulder that juts from Bennu's south pole is about 164 feet (50 meters) high and 180 feet (55 meters) wide. Although some asteroids have moons, Bennu does not. NASA’s OSIRIS-REx mission will reveal Bennu in unprecedented detail. It will collect a sample and return it to Earth in 2023.
10 Need-to-Know Things About Bennu
Found in 1999
Named by 9-year-old
Far from home
Low density
Wave every 6 years
Potentially hazardous
burn up or bolt?
Big Boulder
Moonless
More to come soon
FAQ: Why Bennu?
Bennu is close to Earth, it's really old and well-preserved. It might even help us in our search for clues to the origins of life—and learn how to preserve life by keeping near-Earth asteroids at bay. Read all 10 reasons scientists chose to go to Bennu ›
Resources
OSIRIS-REx mission homepage: https://www.asteroidmission.org/
NASA OSIRIS-REx page: https://www.nasa.gov/osiris-rex
More about OSIRIS-REx: https://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=2016-055A
