Ep. 622: Rockier Moons & Giant Asteroids

Astronomy Cast Ep. 622: Rockier Moons & Giant Asteroids by Fraser Cain & Dr. Pamela Gay So a rock is a rock is a rock. Right? Across the solar system there are giant rocky asteroids and even "gianter" rocky moons. What is the difference between these two families of objects and where do they come from?