Investigating the Effect of the Universe's Expansion on Galaxy Distances

This is a plot of brightness vs. distance of galaxies from every direction that can be observed by the Rubin Observatory. Notice in this plot that in the plot there are galaxies at distances much greater than 13.8 billion light years away. But the Universe is only 13.8 billion years old. Let’s think about how this can happen.

Brightness vs. Distance

Distance (Billion Ly)Observed Brightness (Flux µJy)Brighter