Which term refers to a small solid extraterrestrial body that travels through space?

The term that refers to a small solid extraterrestrial body that travels through space is a meteoroid. Meteoroids are typically defined as smaller than asteroids and larger than atoms, generally ranging in size from a grain of dust to about a meter in diameter. They travel through space and can originate from comets, asteroids, or even fragments of larger celestial bodies.

To clarify the other options: a meteorite is a meteoroid that has entered the Earth's atmosphere and landed on its surface. A comet consists of ice and dust and exhibits a tail when it approaches the sun; it is not solid throughout. An asteroid is a larger solid body, typically found in the asteroid belt between Mars and Jupiter. Understanding these distinctions helps clarify the definition of a meteoroid as the correct answer.