Bennu is a small, near-Earth asteroid that was discovered on September 11, 1999, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey. It is a carbonaceous asteroid in the Apollo group and is classified as a near-Earth asteroid. Bennu is a B-type asteroid, which is a sub-category of carbonaceous asteroids, and is expected to have organic compounds and water-bearing minerals like clays. It is a primitive asteroid that has not significantly changed since it formed nearly 4.5 billion years ago. Bennu has a diameter of approximately 500 meters and completes an orbit around the Sun every 436.604 days (1.2 years) . It comes very close to Earth every six years, within 0.002 AU, and has a 1-in-2,700 chance of impacting the Earth. Bennus density is only about 30 percent more than water, suggesting that it is probably a loose collection of rocks, like a pile of rubble.
Bennu was studied by NASA's OSIRIS-REx mission from 2018 to 2021, which involved a dramatic sample collection. The goal of the mission is to collect a sample from an asteroid and bring it back to Earth. Scientists hope to find organic molecules on Bennu like those that may have led to the origin of life on Earth. Bennu is named after the ancient Egyptian deity linked with the Sun, creation, and rebirth.
