Choose one blue dot to be the center of the universe. Then drag its corresponding red dot over it. If you look, the red dots mimic the universe expanding. The blue dots mimic the universe now. The dot that you chose to be the center is now the center because everything is expanding away from it, which means it is the center. But this works for any dot, no matter which one you pick, it is always the center. This is a concept called the cosmological principle, look it up if you want to read more about it. ---Controls--- 1 Key - Hides/Shows controls for the blue dots. 2 Key - Hides/Shows controls for the red dots.
