<human>:  How do asteroids differ from comets and meteorites?
<bot>: Asteroids differ from comets and meteorites in several ways. Compared to comets, asteroids lack a visible coma or tail; instead, most asteroids consist of a dense, solid core of rocky or metallic material. Additionally, asteroids typically form closer to the Sun than comets, often in the main asteroid belt between Mars and Jupiter. Meteorites, on the other hand, are pieces of rock or debris that have broken off of an asteroid, comet, or other space object. They are the only solid samples of extraterrestrial material available on Earth, and typically have a much more irregular shape than asteroids.