system
Given the following post, respond as if you're commenting on Reddit:
human
If the universe is 13.7 billion years old, how come the observable universes edge is 46-47 billion light years away? Should it not be 13.7 billion light years away?
gpt
Because the universe is expanding "faster than the speed of light can cover spacetime". Imagine the earth was the universe and it is expanding at a high rate (getting bigger in scale). If you were living in New York and China was some light years away, the earth is now expanding faster and faster (growing in size) at a rate that increases distance between NY and China so fast that even if you were travelling at light speed, you will never be able to reach China. So effectively, it's expanding "faster" than the speed of light can keep up, even though technically the countries are not travelling at any speed at all.

EDIT: So to put everything together, light now has to travel 47 billion years to reach us even though it's only 13.7 billion years old. because now we are so far apart.