Here's why:

* Universal Reach: Gravity acts between any two objects with mass, no matter how far apart they are. It's the force that keeps us on Earth, the Earth orbiting the Sun, and the Sun bound within the Milky Way galaxy.

* Weak but Persistent: Gravity is a very weak force compared to the other fundamental forces (electromagnetism, strong nuclear force, weak nuclear force). However, it's a long-range force, meaning its influence extends over vast distances.

* Inverse Square Law: Gravity's strength diminishes with the square of the distance between objects. So, while it's weak, it never completely disappears, even over astronomical distances.

While other forces like electromagnetism can act over long distances, their effects typically weaken much more rapidly than gravity. For example, the electromagnetic force holding an atom together is much stronger than gravity, but it only acts over very small distances.