Hopping space dust makes asteroids look rougher- NASA's OSIRIS-REx spacecraft study

tech.hindustantimes.com:

When NASA's OSIRIS-REx spacecraft arrived at the asteroid Bennu, scientists discovered something surprising about the asteroid's surface wasn't smooth like many were expecting but was covered in large boulders. Now, a team of physicists think they know why.

That popcorn-like effect may even help to tidy up smaller asteroids, causing them to lose dust and look rough and craggy from space.

The researchers published their results July 11 in the journal Nature Astronomy. Their findings may help scientists better understand how asteroids change shape over time -- and how these bodies migrate through space, sometimes bringing them dangerously close to Earth, said Hsiang-Wen (Sean) Hsu, lead author of the study.

"The more fine-grained material, or regolith, these asteroids lose, the faster they migrate," said Hsu, a research associate at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder.

The research began with a few curious photos.

In 2020, a NASA spacecraft named OSIRIS-REx travelled more than 1 billion miles to rendezvous with the asteroid (191055) Bennu, which is about as tall as the Empire State Building. But when the spacecraft arrived, scientists didn't find what they were expecting: The asteroid's surface looked like rough sandpaper, not smooth and dusty like researchers had predicted. There were even large boulders scattered over its exterior.

Now, Hsu and his colleagues have drawn on computer simulations, or models, and laboratory experiments to explore that puzzle. He said that forces akin to static electricity may be kicking the smallest grains of dust, some no bigger than a single bacterium, off the asteroid and into space -- leaving only larger rocks behind.

Bennu isn't alone, said