system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the observable universe have a diameter of 93 billion light years if it is only 13.8 billion years old?
gpt
The universe is expanding.

The vast empty spaces between galaxy clusters are expanding quickly enough to that the very farthest galaxies we can see are moving away from us *faster than the speed of light*.

The light we see was emitted from a very young galaxy 13 billion years ago, by now that same galaxy is 40+ billion light years away.