Moon

In Astronomy the term moon refers to an object that orbits a larger object, with a stellar system.

By the mid 20th century Astronomers had identified close to 100 moons, in addition to Luna, Planet Earth's moon, orbiting other planets. As the power of 20th century telescopes improved asteroids were found that were also orbited by smaller objects, and these too are called moons.

Some trans-Neptunian objects are orbited by moons.

Some notable moons in the Solar system

name	principal	diameter	notes
Ganymede	Planet Jupiter	5,268 kilometres (3,273 mi)
Titan	Planet Saturn	5,150 kilometres (3,200 mi)
Callisto	Planet Jupiter	4,821 kilometres (2,996 mi)
Io	Planet Jupiter	3,643 kilometres (2,264 mi)
Dimorphos	Didymos		The DART space probe was designed to collide with Dimorphos, to study the feasibility of making minute changes to asteroid's orbits, in case we ever want to divert an asteroid we detect is on an orbit where it will collide with Earth.