Scientists thought asteroid Bennu's surface would be like a sandy beach, abundant in fine sand and pebbles, which would have been perfect for collecting samples. Past telescope observations from Earth's orbit had suggested the presence of large swaths of fine-grain material called fine regolith that's smaller than a few centimeters.

But when the spacecraft of NASA's University of Arizona-led OSIRIS-REx asteroid sample return mission arrived at Bennu in late 2018, the mission team saw a surface covered in boulders.

Two NAU astronomers presented groundbreaking research at the annual meeting of the Division for Planetary Sciences, a branch of the American Academy of Sciences.

Where does Earth's water come from?

A Northern Arizona University researcher who studies active asteroids, which are rare asteroids with comet-like tails, presented groundbreaking research today at the annual meeting of the Division for Planetary Sciences, a branch of the American Academy of Sciences.

Colin Chandler, a doctoral student in the Department of Astronomy and Planetary Science at Northern Arizona University and recipient of the NSF Graduate Research Fellowship, presented "Recurrent activity from a Main Belt Comet."

Active asteroids hold clues about the origins of water on Earth and where water can be found today in the solar system. Fewer than 30 of these objects have been discovered since 1949. Most recently, asteroid (248370), also known as 2005 QN173, was found to be active on July 7. Chandler began digging into historical astronomical data to learn more about the object's past, and he and co-authors Chad Trujillo of NAU and Henry Hsieh of the Planetary Science Institute discovered an image from July 2016 that showed the object with a long, thin tail.