Here's why:
* Newton's Law of Universal Gravitation: This law states that the force of gravity between two objects is directly proportional to the product of their masses. This means if you decrease the mass of one object, you decrease the product of the masses, leading to a decrease in the gravitational force.
* Formula: The formula for gravitational force is:
```
F = G * (m1 * m2) / r^2
```
where:
* F is the force of gravity
* G is the gravitational constant
* m1 and m2 are the masses of the two objects
* r is the distance between their centers
As you can see, the force (F) is directly proportional to the product of the masses (m1 * m2). So, if you decrease either m1 or m2, the force will decrease.
