Knowing that you are studying astronomy, a curious friend asks where the center of the universe is located. You answer “Right here and everywhere." Explain in detail why you give this answer.

The universe we observe is isotropic, meaning it looks the same in all directions. When we look out into space, we see that galaxies, stars, and other celestial objects are spread out evenly, no matter where we look.
This uniformity suggests that there is no preferred direction in space.
This isotropy also applies to the cosmic microwave background radiation. This ancient light left over from the Big Bang shows uniform temperature in every direction as well.
This isotropy is a key part of why there is no single center of the universe.
Because everything looks the same no matter where you are, every point can be considered as the 'center' from an observational standpoint.

Our universe has been expanding ever since it began with the Big Bang.
Think of the universe as a balloon with spots drawn on it.
When you blow up the balloon, the spots move away from each other.
This is similar to how galaxies are moving away from each other as space itself expands.
Because the expansion happens uniformly, every point in the universe is moving away from every other point.
So, no matter where you are, it appears as if you are at the center of this expansion.
This uniform expansion is another reason why asking for a 'center' of the universe doesn't make sense the way we usually think about centers.

The Big Bang Theory is the leading explanation for how the universe began.
It states that the universe started from an extremely hot and dense point about 13.8 billion years ago and has been expanding ever since.
Initially, all matter and energy were contained in a very small space.
Then, in less than a second, this point expanded rapidly in a process known as inflation.
As the universe expanded and cooled, particles formed, eventually leading to atoms, stars, and galaxies.
Because the universe started from a single point and expanded uniformly, every point you observe now can be considered as originating from the Big Bang.
This is why every location in the universe can be perceived as 'the center' when discussed in this specific context.