Asteroids may be wondrous windows into the history of the cosmos, but the unfortunate reality is that they are also pretty drab. They are very, very similar in terms of the way that they experience space weathering,” she said. Among their many findings is some clarity on the colorful mystery, that likely has a lot to do with age. Rubble pile asteroids like Ryugu and Bennu have their own physiological cycles that slowly shift their surface debris. However, Bennu,has a surface that’s experienced the same cosmic environment for tens of thousands of years.