Note 4

Part 1

## Spacetime Model

This webpage is part of www.mass-gravity.com

This figure is not exact because an amount of spacetime always exists between the two (or more) closed volumes. To understand what happens, let's consider the following thought experiment.

1. If the distance between the two spheres were null as shown in the figure, the internal spacetime wouldn't exist. So, the pressure would come exclusively from external spacetime. This is shown by the arrows.
2. Now, let's increase the space between the two closed volumes from 0 to "d". A small pressure on the internal side of each closed volume will appear. This pressure will increase from 0 to "P".

So, there is a relation between "d" and "P". Whatever the distance "d", this distance will be always smaller than the infinite (here we say "infinite" but in reality, the universe is probably finite). It means that if the distance between two object exceeds the radius of the universe, we could have a repulsive force between the two objects. In this case, the pressure force comes from the internal spacetime between the two objects.

Important: This phenomenon, which makes the gravity force repulsive instead of attractive, may explain the expansion of the universe greater than that expected.