What is the center of the universe? The answer is ridiculous

What we know is that the universe is expanding. But what expands inside? Is there a center for this expansion?

One thing we know for sure is that the universe is expanding. We understood this almost a century ago thanks to the observations of the American astronomer Edwin Hubble. He discovered that galaxies were moving away from us at a speed proportional to their distance from the Milky Way. This does not mean that there is anything special about our location in the universe: the distance between any two galaxies grows with time. Einstein's relativity tells us why, which posits that space is not static, but can warp, stretch, and bend. One of the questions you often ask us in the comments is: What is the universe expanding into? Is there a center for this expansion? Let's try to understand this with Professor Amedeo Balbi from Tor Vergata University in Rome (Here is the video).

This is why the universe has no center

We assume that the universe is not expanding into something, because the universe itself is all that exists. There is no external space in which expansion occurs. The reason many people ask this question is because they view the expansion incorrectly, as if galaxies were tossed apart by the explosion of the Big Bang. In reality, things are not like that, because it is space that is expanding, and galaxies are still in space but are being pulled away due to the expansion. This happens in the same way throughout space. Imagine the panettone dough rising and the raisins inside the dough moving away from each other over time. They stay still, and it's the dough that rises and makes them move away.

Well, if you picture things this way, then you not only understand that we don't have to imagine something in which expansion is occurring, but that there isn't even a center of expansion. Every point in the universe is equivalent to all other points. If we were to observe objects from another galaxy, we would see other galaxies moving away from us just as they do from our vantage point. Therefore, there are no distinct locations in the universe and no center of expansion. Expansion occurs in exactly the same way throughout space.