The number of galaxies flying towards each other is reduced by them either colliding and merging or missing and drifting away. This occurs after a finite amount of time, while drifting away can, in principle, last an infinite amount of time.
The number of galaxies flying towards each other is reduced by them either colliding and merging or missing and drifting away. This occurs after a finite amount of time, while drifting away can, in principle, last an infinite amount of time.
One thing about gravity is it doesn't take any time for gravity to be felt. Gravity is actually warping of Spacetime, so it doesn't travel across a distance to cause it's effect. The effect is actually the formation of the universe itself.
Light does take time to reach us. When we look at things far away, we are also looking at them a long time ago. As the light traveled to reach us, billions of years may have passed, during which time the galaxies were moving and doing things to each other (that we don't know about, and haven't seen, cuz the light didn't get here yet) but the gravitational effects of the interactions and changes has already occurred.
This not only boggles the mind, it also bolluxes up astronomical calculations.