The asteroid’s big secret, revealed.
NASA via Giphy
When scientists first observed the asteroid Bennu up close in 2018, they were shocked to find that its surface was covered with sizeable boulders.
But it turns out the asteroid is able to maintain huge clumps of rock in the harsh environment of space — igniting new questions about asteroid evolution and erosion.
Both objects are considered Near Earth Asteroids, meaning they not only orbit relatively close to our home planet but they’re also exposed to quite a bit of solar radiation.
And they’re comparatively smaller than other asteroids out there.
For example, Bennu has a diameter of 0.3 miles, while the much smoother asteroid Eros (below) has a diameter of almost 10.5 miles.
AXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST
Regolith exists on Bennu and Ryugu as well, though the researchers wanted to understand why it’s less abundant than on other asteroids.
For the study, they modeled two hypothetical asteroids — one with a radius of .5 kilometers and the other of 5 kilometers.
After tens of thousands of simulated years in space, conditions became ripe for a phenomenon called electrostatic lofting to take place.
NASA/Goddard/University of Arizona
It’s only on smaller asteroids that charged particles would be able to pop off of the rock entirely, since the pull of gravity isn’t strong enough to bring them back down to the surface.
Now, scientists will put the models to the test.