NASA’s OSIRIS-REx Mission Explains Bennu’s Mysterious Particle Events

The OSIRIS-REx spacecraft first detected particle ejections from asteroid Bennu in January 2019 — rock fragments as large as 10 centimeters were flung off its surface! Two more particle ejection events later, the science team has determined that the fragments came from several different locations on Bennu’s surface, not only from a single source. Several ejection mechanisms are possible: impacts from very small asteroids, rapid loss of water in the afternoon sun (like popcorn), or thermal stress in the afternoon sun. READ MORE

This view of asteroid Bennu ejecting particles from its surface on January 6 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft. Image credit: NASA/Goddard/University of Arizona/Lockheed Martin