Asteroid

space · rocky bodies · solar system · geology

Made of three types. Asteroids come in three main flavors: carbonaceous (rocky), metallic (made of metal), or silicaceous (made of a rocky mineral called silica). Each type tells us something different about how our solar system formed.

Between Mars and Jupiter. Most asteroids orbit in the inner Solar System, with a huge belt of them floating between Mars and Jupiter. Some asteroids even share Jupiter's orbit around the Sun.

Wildly different sizes. Asteroids range from tiny space rocks smaller than a kilometer across to Ceres, a dwarf planet nearly 1000 kilometers wide, which is bigger than many countries.

No air or tails. Unlike comets, asteroids have no atmosphere and no tail, even when the Sun warms them up. This difference helps scientists tell them apart in space.

Rubble piles in space. Many asteroids aren't solid rocks but rather loose collections of boulders held together by gravity, like floating piles of cosmic rubble.