What is the dominant force between astronomical objects? Why are the other three basic forces less significant over these very large distances?

The four fundamental forces are listed below,

(1) Strong nuclear force.

(2) Weak nuclear force.

(3) Gravitational force

(4) Electromagnetic force.

Gravitational force is the dominant force between astronomical objects. These forces are attractive and dormant in nature. It determines the motion of stars, galaxies, planets, and moons.

The relative strength of the gravitational force is of the order of ${}^{{10}^{-38}}$. The gravitational force helps one object to attract the other object in the universe. Gravitational force is the weakest force, but its range is the largest as it helps in determining the motion of astronomical objects like planets, galaxies, stars, and moons.

The other three basic forces are the strong forces than the gravitational force, but they have very less working range than the gravitational force.

Therefore, the other three forces are less significant.