Question

One force is responsible for holding together stars with planets, planets with moons, and stars in galaxies. What is this force?

Answer 1

This force is known as gravitational pull (gravity). This is caused by an uneven balance between mass and energy, creating a forced circular motion known as "orbit".
I hope this helps!

Answer 2

Gravitational force

Step-by-step explanation:

Gravitational force is a fundamental force which acts between any two bodies having mass. It is an attractive force. It is proportional to the mass of the two bodies and inversely proportional to square of distance between them.

It is due to gravitational force that holds planets with stars, moons with their planets and stars in galaxies. Had there been no gravitational force, the stars would not have formed and for the fact, any other body in this universe. Gravitational force causes the moons to revolve about planets, planets to revolve about star and star to revolve about the center of galaxy.