Here's why:

* Mass: The Sun is incredibly massive, containing over 99.8% of the total mass of our entire solar system. Earth and the Moon are significantly smaller in comparison.

* Gravity's Relationship to Mass: Gravity is directly proportional to mass. The more massive an object is, the stronger its gravitational pull.

Therefore, the Sun's enormous mass creates an immense gravitational force that keeps Earth, the Moon, and all the other planets in our solar system in orbit around it.