Imagine the galaxies going east at 20 times c(pure guess) and galaxies to the west going at 20 times c. That's pretty quick between them. The same with the north and south.
AT those velocities......imagine how fast the area, and then the volume, is multiplying. That volume is between us and them. Not behind us.
This is big doings. That's amazing. It's an amazing growth rate. An ongoing creation of some sort. A creation of distance, not mass.
What size would result from such a 13 billion yr. expansion? It's a whopper.
If long reaching gravity is due to mass density, this universe is losing density at a very high rate.