Here's why:

* The Moon has a finite size: The Moon is a sphere with a specific diameter, so any crater, no matter how large, cannot extend beyond its surface.

* Impact craters have a depth limit: The depth of an impact crater depends on the size and velocity of the impacting object, as well as the composition of the lunar surface. While some craters can be quite deep (like the South Pole-Aitken basin, which is around 13 kilometers deep), they always have a bottom.

* Gravity: The Moon's gravity prevents any object from falling infinitely into a crater. Even if a crater were extremely deep, the object would eventually reach the bottom due to gravity.

While the concept of a bottomless crater is intriguing, it's not scientifically plausible on the Moon or any other celestial body.