If the Universe is expanding, where is the centre?

If you have any other analogies that help to picture what's going on with the expansion of the Universe or what happened in the Big Bang, let me know in the comments below!

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👩🏽‍💻 I'm Dr Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.

[DrBecky]

Just to clarify something I said at the end. If you take into account the expansion of the universe, then the galaxies on the edge of the observable universe which emitted their light 14 billion years ago will now be 46 billion light years away. Both are correct statements. It’s a difference between the “look back time” and the “proper distance” both of which are considered distance measures in cosmology 👍

[ZacharySound]

It indeed does have a center. I see it every time I look in the mirror.

[essaboselin]

I prefer the loaf of raisin bread dough analogy myself. It expands as it rises, it's not a surface, the raisins don't stretch it rises, etc. More importantly, it tastes better than a balloon when finished.

[northerniltree]

Milky Way has a soft, chewy nougat center. I learned this early in life.

[garettjames]

"The Universe doesn't have a centre." 8 minutes in "Well, actually we just don't know."

[alexandermold]

I always though there was a restaurant at the end of the universe

[lesfrisbees]

I was scratching an itch above my ear right as you said “right there, above your ear.” Freaked me out a bit!

Fantastic video as usual. So glad I found this channel.

[solmetts]

Thanks! Could you sing the entire Galaxy song, please 🙏🏾 I can’t wait to hear you sing the last line 😂 I’m Smeth-en ❤

[TimberGeek]

"No matter where you go, there you are."

[dat_chip]

The diagram of the universe saying "NB: Not to scale" had me laughing!

[I_Don_t_want_a_handle]

The Centre of the Universe is where my cat sits. I know this because he told me this, quite forcefully, the other day.

All Hail the Masters!

[alexanderperry]

Not only does my cat beg to differ, it also knows EXACTLY where the centre of the universe resides ...

[niranthbanks]

You made a difficult topic much more clear! I love those “haha moments”.

[Mortone]

Difficult “for the brain to get its head around.” Priceless. Love your explanations.

[PalimpsestProd]

Why will you "professionals" never admit that the universe has a center and it's chewy.

[thomashounsome]

Excellent video, thank you. Taking a massive subject like that and making it understandable to those without a college education like myself is a talent in itself. Also nice Monty Python reference!

[joppo]

Hi Dr. Becky, I just discovered your channel yesterday and it is everything i was subconsiously looking for. I just ordered your book online and i hope to read it soon! thank you and keep up the enthousiasm!

[kevinrice]

Minneapolis. The center of the known Universe is Minneapolis. I heard it once on the Mary Tyler Moore show, and I've remembered it all these years later, because it's the kind of thing that it's great to have a definitive answer to.

Just like, what's the hottest temperature? it's 1 Gruhn. We decided in college that the temperature scale should have an upper bound, too, so on a scale from 0 to 1, where 1 is the Big Bang, the Gruhn scale almost always is near zero on Earth.

[kardRatzinger]

"This is difficult for the brain to wrap its head around" :)
Love it.

[Tommo]

I have some questions about the "big bang".
(genuinely interested in answers, not to argue).
1. When we look at distant galaxies that we say are "further back in time" due to how far away they are, and then we are told that these distant universes are "older" meaning the light we receive from them took so long to get to us from there that we can literally see back in time to the big bang. How is it that we can apparently see back to the origins of the big bang? If everything is expanding outward, and space itself is expanding (carrying us with it) faster than the speed of light, how is light then able to reach us from back in time when the big bang happened?
2. It is said that the big bang didn't happen in a "location" in space, but then I hear the same people also say that everything was once contained at a single infinite "point" prior to the big bang and then "BANG" everything that was contained in that single point is now shooting through space at incredible speeds and even space itself is expanding outward... Why do physicists say everything was once contained in a "single point"? How is it possible for a "point" to exist if spacetime itself was contained within that point?
3. Why do physicists say that the distant galaxies we see are "old" in the sense that they represent a time closer to the origin of the big bang? I understand the concept that the light we see from distant galaxies takes a very very long time to reach us, which means the light we are seeing is what that galaxy was like when the light first started traveling toward us, but how does this mean that the "old" galaxy we see has anything to do with the origins of the big bang, and how could we possibly measure how close that is to the origins of the big bang?
4. If we are moving with space at a greater speed than light (because of space itself expanding) this means that there are galaxies moving away from us that we will never see because the light will never reach us unless we one day learn to fold space ourselves, so we can't measure how vast space is exactly. Heck, some say space is infinite. How could we ever possibly know the origins of the big bang if we can't measure space?
5. How could we possibly tell that "the universe" is expanding "outward" if we can't actually measure the size of the universe in its entirety? Is it not just as likely that space (if its finite) outside of our observable universe is trillions of times bigger than our current observable universe and as a whole isn't actually expanding outward, and what we see isn't the whole story? For example, I could observe the atmosphere here in Australia and I could theoretically (with enough data) predict how the weather is going to behave long into the future, but if my observations were confined to the atmosphere within/above(?) Australia only, and I could not observe the outside world, It is not possible to predict the weather long into the future because it is only a small part of what is happening on a larger scale. Is it possible that the expansion of our current observable universe is just a small part of what is actually happening on a much larger scale outside of what we can currently observe? Isn't it just as likely that galaxies outside of where we can currently observe could actually be expanding through space toward us, as the "Big Freeze" theory that we will just continue expanding outward and eventually just fade into darkness?