re: #747 Spenser (with an S)

Asteroid: A relatively small, inactive body, composed of rock, carbon or metal, which is orbiting the Sun.
Comet: A relatively small, sometimes active object, which is composed of dirt and ices. Comets are characterised by dust and gas tails when in proximity to the Sun. Far from the Sun it is difficult to distinguish an asteroid from a comet.
Meteoroid: A small particle from an asteroid or comet orbiting he Sun.
Meteor: A meteoroid that is observed as it burns up in the Earth’s atmosphere - a shooting star.
Meteorite: A meteoroid that survives its passage through the Earth’s atmosphere and impacts the Earth’s surface.

Are they made of the same materials?