So, this is a dumb question but a bit of information confused me lately. Before, I figured galaxies were no longer visible by us because their luminosity decreased in an inverse square manner. However, while watching a movie I stumbled upon the concept of how galaxies disappeared our sight because the space which both galaxies occupy is moving away from each other faster than the speed of light. I understand nothing can move faster than the speed of light, but the argument here, I guess, is that space itself can move, as a consecuence of the Big Bang, faster than the speed of light. Once again, sorry for the silly question but being tired and thinking can really mess up ones mind. Thanks in advance!
It would be more correct to say that distant galaxies appear than to say they disappear. Based upon the accepted big bang theory, there are galaxies that formed early in the universe from which light has not yet reached us, but that will reach us in the future. On the other hand, accelerating expansion of the universe could cause light emitted after a certain time from a galaxy currently visible to never reach us; however, increasingly red-shifted, ever dimmer light from such a galaxy would continue to be observed.