There is a fundamental misunderstanding in your question. There is not only one moon in the universe. Here's why:

* Our Moon: The Moon we see in the sky is Earth's natural satellite.

* Other Moons: Many other planets and dwarf planets in our solar system have moons. Jupiter has over 70 known moons, Saturn has over 80, and even Pluto has five.

* Exomoons: We are even starting to discover moons orbiting planets outside our solar system (exoplanets), which are called exomoons.

The misconception likely comes from the fact that:

* We only see one moon from Earth.

* Our moon is the largest and most visible natural satellite in our sky.

Therefore, it's easy to think it's the only one, but the universe is full of moons!