Take a look at this image of Bennu and notice the material being ejected from the surface in the middle of the image. We are seeing an extremely rare “active” asteroid for the first time up-close. According to Dante Lauretta of the University of Arizona, "probably the biggest surprise of the early stages of the OSIRIS-REx mission and, I would say, one of the biggest surprises of my scientific career".

Since Osiris-Rex’s arrival in January this kind of event has been observed at least eleven times with three of events ejecting over 100 observable particles. There is no official theory as to the cause, but they suggest that these particles ultimately go into orbit for a spell and eventually return to the surface of Bennu. Which explains why after billions of years the rock hasn’t whittled away to nothing.