If the Universe is about 13.7 billion years old, and the diameter of the observable universe is 93 billion light years, how can it be that wide if the universe isn’t even old enough to let light travel that far that quickly?
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Imagine the universe is a balloon that is slowly inflating, now imagine your beam of light is an ant crawling along it’s surface.
Lets say the ant moves 10 inches in some frame of time, and the balloon also expands to twice its size in that same time, the ant will be more than 10 inches away from where it started from.
If you ignore the expansion of the universe – the ant appears to be moving faster than it should be able to move.
If you consider that expansion though, the ant isn’t moving any faster or slower… the space around the ant is moving away from it.
It’s the same deal with light in space, the space between us and that light has expanded, which makes the distance between us and that light farther than the light itself has actually travelled.
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