That is a way of measuring the speeds at which stars and galaxies are moving away from us.
Our galaxy is moving and spinning at a considerable rate.
As the Universe expands, the galaxies move apart from one another.
Moreover, the more distant galaxies are moving away from Earth faster than those closer by.
In Friedmann's model, all the galaxies are moving directly away from each other.
Is the galaxy moving at the speed of light?
This means that the galaxy is moving towards the Earth.
First, I was not aware that anybody thought all the galaxies were moving in the same direction.
Then he proved the galaxies were moving away from each other.
Sure enough, all the galaxies were moving away from our galaxy.