Which of the following statements about the force attracting these two galaxies is true?

a) it is the same force that causes an apple to fall to the ground.
b) the force will get weaker as time passes.
c) it is a mysterious force, whose nature remains completely unknown to scientists.
d) it is a force unlike any force that we ever experience on earth.

The force that makes two galaxies to be attracted to each other is the same force that causes an apple to fall to the ground. This is known as the Gravity Force.

This force was named by Issac Newton, after some empirical observations in nature and then he published the Universal Law of Gravitation on 1687:

The force exerted between two bodies of masses and  and separated by a distance is equal to the product of their masses and inversely proportional to the square of the distance.

Written in a mathematical form is:

Where is the gravitational constant

So, this force between two bodies (two galaxies or an apple and the ground) is directly proportional to the product of the mass of both and inversely proportional to the square of the distance that separates both bodies.

This means the gravity force decreases when the distance between these two bodies increases.

Therefore, the correct option is a.

brave new world, aldous huxley (1932)