Asteroids have been lyrically described by planetary scientist Erik Asphaug as scraps on the floor of the planetary bakery, and indeed many tons of those scraps fall to Earth every day. Unlike bakery crumbs, asteroids and their icy cousins, comets, are unexpectedly varied. Many asteroids are oddly shaped as you can see in the images that appear with the online version of this Quick Study. Kleopatra, for example, looks like a dog bone and Eros resembles a tooth. Others are round or, like Saturn’s moon Pan, flattened like a cosmic pierogi. And the comet 67P/Churyumov–Gerasimenko actually has sand ripples.
You might expect that banging stones together on Earth or in space would produce similar outcomes, but few terrestrial rocks are as peculiar as Kleopatra and company, and much of the diversity seen on our planet is produced by geological forces or erosion by wind or water that asteroids and comets...
