The Big Dipper doesn't *have* 7 stars, it's made up of 7 of the brightest stars in the constellation Ursa Major (the Great Bear).

Here's why:

* Ursa Major is a much larger constellation than just the Big Dipper. It contains many more stars, but the seven that form the familiar dipper shape are the most prominent and easily recognizable.

* These seven stars are relatively close to Earth and are therefore very bright.

* The Big Dipper is a useful navigational tool because of its distinct shape and easy visibility. This is why it has become such a familiar and important part of our night sky.

So, the Big Dipper isn't a constellation itself, but rather a recognizable asterism (a pattern of stars) within the larger constellation of Ursa Major.