One of the mysteries of the expansion of the universe is that it expands where there is no gravity. In other words, the expansion of the universe cannot be
explained by simply changing the distance scale. Let's try to find a simple explanation for this phenomenon.
And what if the distance scale changes unevenly in the universe. After all, if it changed in all parts of the universe in the same way, then we just
they would not have noticed this change. We would not feel it if the size of all the atoms, the radius of the Earth, the distance from the Earth to the Sun and from the Sun to
before the distant gplactics would have changed in the same number of times.
It is known that the scale of distance and time increases in proportion to the gravitational potential, respectively, it decreases with a decrease
in the gravitational potential.
Let the gravitational potential in intergalactic space be
, and we are inside the galaxy, where the full gravitational potential is
gravitational potential of the galaxy .
Now, after a while, let the gravitational potential of the Universe between the galaxies decrease and become
Then the total gravitational potential inside the galaxy will become
It is easy to see that the gravitational potential between galaxies will decrease by a large relative amount, because
For example, if
accept as 100%,
inside the galaxy's gravitational potential will become 0,98039% of the initial , and between the galaxies he will be 98%.
The distance scales will also change accordingly, but we will not notice that our distance scale has become 0.98039% of the previous one, we will only notice that between
the distances between galaxies increased by 0.00039% . This is why it seems to us that the universe is expanding where there is no gravity.