Simple Physics Solves Mystery of Diamond-Shaped Asteroids
New computer models using simple granular physics have been able to match the curious diamond shape of asteroids like Bennu and Ryugu.
In our never-ending quest to understand the universe, and especially our own solar system, sometimes you have to go back to the same well over and over. We’ve already talked about several asteroids today and how difficult they can be to image. That’s particularly concerning when they are near-Earth asteroids, so we keep sending missions to asteroids to understand their composition and their history. All the information we gather can lead to not only learning more about the history of our solar system but also what kind of threat some of these asteroids present for our humble blue dot.
This brings me to two of our favorite asteroids — Bennu and Ryugu. Bennu, of course, was visited and sampled by the OSIRIS-REx mission after CosmoQuest’s dedicated team of volunteers mapped thousands of images and millions of rocks, boulders, and craters to help find a relatively safe place to sample. That sample will be here on Earth in 2023.
But sample return missions aren’t the only things these two asteroids have in common. They are also diamond-shaped, rubble pile asteroids. They are made of bits of rock and dust that have managed to clump together without a whole lot of compression or gravity. In fact, OSIRIS-REx principal investigator Dante Lauretta called Bennu a “ball pit”. The samples taken of both asteroids were much larger than expected, and OSIRIS-REx’s sample arm dove almost a half meter into Bennu itself.
How did these asteroids come to have their distinct diamond shapes, though? This question has been an interesting area of research for planetary scientists. Clearly, they don’t have enough gravity to become spherical. They’re not big enough. Now, thanks to a team of scientists from the Okinawa Institute of Science and Technology (OIST) and Rutgers University, we may have found the answer, and it turned out to involve simple physics. (If physics can…