Asteroid Bennu's mysterious missing craters suggest 'impact armoring' protecting the surface

I note this in the report.

"Bennu has offered other surprises as well. When analyzing the characteristics and distribution of the asteroid's craters, the scientists realized that unlike the moon, Bennu doesn't keep a very long record of its past encounters. On average, traces of past events are wiped out every few million years, and while the asteroid itself is up to a billion years old, its constantly changing surface is relatively young. "Based on the observed crater population, you can estimate the age of the surface," Bierhaus said. "For Bennu, we got something like 2 million years, and that is remarkable. It's one of the youngest crater-derived surface ages we've seen in the solar system." The finding challenges some earlier assumptions about the life of asteroids. On these "geologically dead" bodies, without volcanism and weather-producing atmospheres, clearly other phenomena are at work that keep them more alive than one would expect, Bierhaus said. "We thought we had some basic understanding of all the different ways that impact cratering could manifest," he said. "And it was surprising to look at Bennu and find that there is a whole new regime that we just haven't fully appreciated before."

Perhaps Bennu surface is just young and not an object one billion years old or so in the solar system. Reconciling different ages reported for different objects in the solar system with radiometric ages of meteorites (commonly reported near 4.56 billion years old), involves much juggling to reconcile. Bennu is another indicator of catastrophism operating in the solar system too, and perhaps not 4.5 billion years ago but much more recent.