ASTEROIDS GALAXY TOUR: Ryugu’s rubble suggests its short life has been rather turbulent. “The asteroid Ryugu is a loose assemblage of fragments from a collision between two asteroids, according to new research published Monday in the journal Nature Astronomy. Some asteroids are composed of large, solid pieces of rock, but Ryugu is more like a rubble pile than a rock. It is too small and fragile to have remained intact for very long — scientists estimate Ryugu formed between 10 million to 20 million years ago.”

The sort of asteroid that’s easier to mine, but harder to deflect if it’s heading toward Earth.