Here's why:

* Size: Comets are relatively small, ranging from a few meters to tens of kilometers across. The moon, on the other hand, has a diameter of about 3,474 kilometers.

* Composition: Comets are mostly made of ice, dust, and rock. The moon is primarily composed of rock and metal.

* Density: Comets are much less dense than the moon due to their icy composition.

To give you a sense of scale:

* The mass of the moon is about 7.34 x 10^22 kilograms.

* The mass of a typical comet is estimated to be around 10^13 to 10^16 kilograms.

This means that the moon is billions of times more massive than a typical comet.