system
Given the following post, respond as if you're commenting on Reddit:
human
If you traveled faster than the expanding universe, where would you eventually end up?

In other words, what is the universe expanding into?
gpt
It is space itself that is expanding.  No matter how fast *you* travel, you're still occupying spacetime.  Imagine you live on the surface of a balloon, and the balloon is expanding.  No matter how fast you run around the surface of the balloon, you're still on the balloon.  You don't wind up anywhere except the universe.