How to determine where the edge of the universe is and where is its center?
Since other galaxies are far away from us, we may falsely appear as if the Earth is at the center of the universe, but in fact, this is completely wrong. In fact, there is no center. According to the expansion model, any group of galaxies can be said to move away from another group.
Whatever galaxy you live in, whatever planet you live on, everything around you will look approximately the same. And if the principle of expansion would operate on our planet, as well as in the universe, then the distances between cities and various objects would constantly increase. Cities would move away from each other constantly, more and more. At the same time, none of the city can be considered as something special, central. From a global point of view, absolutely every city can be considered central.
But shouldn't the center be somewhere, even if we cannot define it?
Astronomers looking at the galaxy, which is five billion light-years away, see it as it was in the past, as it was five billion years ago, and not as it is now. Physicists are convinced that the speed of light - the cosmic speed limit - nothing can go faster. No matter how unusual and powerful our instruments are, there is a limit to how far we can peer into space.
This limit is set by the age of the universe. If it's 13.7 billion years old, we can't see anything more than 13.7 billion light years away.
The universe has no center, as well as no edges. For us, the "Edge of the Universe" is just the limit of visibility.