If the Universe is expanding, where is the centre? 

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 👍

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

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

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

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

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

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.

After watching videos like this, I need to lay down and let my brain cool off...😊

"The universe doesn't have a centre" and "We don't know where the centre is" is NOT the same statement

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

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

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!

I once asked a science teacher in high school back in the mid-80s "If the universe is expanding what is it expanding into?" He gave me a confused look and said he didn't know. An honest answer from someone who was a high school science teacher in the mid-80s and not an astrophysicist.

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

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.

As it is hard to wrap your brain around the entire universe expanding uniformly from our position within the universe, I find it easier to picture it as everything in the universe shrinking while the universe stays static.

I think there are misconceptions on both sides. I think it really depends on the shape of the universe, if there is one. If the universe is sphere then it would indeed have a center. But this is something we will likely never know.

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!

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!

The most comprehensive explanation of big bang and the expanding universe. I think it's also because you explained it together.

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

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

Thank you for your input. I'm no astrophysicist, but have always been a science minded person. I really enjoy your videos.

Dr. Becky is the center of my Universe, my love expanding with each new video

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

of course it is difficult to "wrap your head around that fact" - since wrapping around something indicates there is a centre.

what a superb explainer you are. Thank you so much for providing these videos!!!

Although I am not good at math I am good at understanding what you are presenting. My mind is constantly multitasking all the new things in life that need to be grasped from the birth of humanity to the why's of creation.I really learn a lot from you because you summarize concepts that I do not have the time to fathom, This makes you special in my reality and I thank you greatly.

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.

If "we" aren't creating more space-time 'fabric' and just "stretching" it, how far can space be expanded before space-time 'rips'?

Thank you for precisely pointing out the limitations of the standard analogies.

You're content is awesome and you have a great singing voice! Thank you :)

One of the problems with describing the universe is using the word "smaller", which often shows up in descriptions of the universe at the "big bang". But telling someone something was "smaller" is one reason why the images people have of this event (or more technically, these events) trend toward the typical chemical explosive bombs used to picture "the big bang". A better way to describe the (relative to us) early universe is that the universe was _more dense_ , so incredibly dense that even objects like protons could not exist. What we know today as normal matter could not exist because the energy density was too high. It is this key concept that has to be stressed: the universe was _different_ before the state in which we find it today. What we observe today could not exist until the universe underwent a change of state. The challenges of pedagogy surrounding much of modern physics ought not be discounted. Popular presentations of concepts in fields of study like cosmology will lead to misconceptions if time is not taken to work though the many ways in which people can and will misunderstand what is being explained.

Thanks for the singing at the end, I'm having that song at my funeral.

The fact that we imagine that the expansion of the Universe is a stretching is why everyone wants a centre to the Universe. The thing is everything is moving away equally and in every direction at the same time.

I loved this video thanksbi learn a lot from it

There is a problem here! With us expanding like this I have noticed that my CLOTHES are not expanding at the same rate I am! On another note, if we had a very fast space ship I can see it would be VERY easy to get utterly lost out there!

Wow, never thought about the universe like that, thanks, great vid.x

Thank you for telling us about the balloon analogy. You did a great job! 😉🙏

I guess you can say that the observable universe has a center, and that center is us

5:41 _"There's nothing to do with 'higher dimensions' or anything like that that's driving the expansion"_ Dr Becky, subtly making String Theory fans cry.. 🤔😉😂

I love your enthusiasm, the sher joy of what your talking about is intoxicating, reminds me so much of brain cox there is so much passion behind it.

Brilliant! The best explanation I saw so far. Merci 🙏

a refreshing down to earth, clear, no nonsense style.

While the universe not having a 'center' is fairly perceivable under this description... I think what people are trying (and struggling) to comprehend is the "starting point." The brain naturally assumes that the 'Big Bang' must have started somewhere, and I think people just find it easy to try and label that 'starting point' as the 'center' of the universe. In other words, when the scientists say all matter was pressed down into an inconceivably small point before suddenly expanding outwards... people are presuming there must be a location, somewhere, where that infinitesimally small 'singularity' of matter started out, before 'exploding' into it's expanding state... and therefore, it's difficult for them to conceptualize why we're unable to pinpoint that particular location.

Missing a coordinate: WHEN is the center.

So well explained. Thanks.

Well explained. Thank you!

I've thought about this lots but struggled to wrap my head around it. This helped me a bunch.

I already have a deep love for astronomy and the cosmos, but man I wish you were my teacher in high school (or college)! Love learning more here!

This is the best explanation I've heard so far!

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?

Wait so it’s all the center? Always has been.

Just excellent. You are passing on your love of astronomy to others in a way for everyone to grasp! :-)

Thank you for keeping it clean. Not adding another dramatic music.!

thanks for this video. I've always struggled with this idea from astrophysics. Bag that balloon analogy!!

Depending on how you look at it, I guess the centre is based on your perspective... and you can’t really take away your perspective to see which way which galaxies expand to. Some interesting stuff!

Was the universe infinitely big when it was smaller then an atom at the moment of Big Bang?

OMG perfect video...I've been commenting all over StarTalk about this trying to wrap my head around it. Exactly what I've been looking for. Like and Subbed! I started thinking more about plants growing to help wrap my head around it until just now seeing this video. As plants grow, the whole plant itself is getting bigger so any two or three points are always getting further from each other, but not from a central point. But it does make me wonder about what you said near the end, maybe we need to zoom out. It so odd to imagine everything just popping into existence and then expanding but not from a central point. Yea I'm starting to go backwards again haha....wouldn't it have to have come from a central point if everything fit into an infinitesimal small point and then grew? That's why I'm liking the idea that we just can't see the bigger picture.

Dr. Becky did a great job keeping it simple

This has always puzzled me. Yours is the first explanation that helped make this complex concept understandable. Thank you!

I believe Henry of minutephysics called "big bang" "everywhere stretch" in one of his videos ages and ages ago

I am so happy that I have stumbled upon your channel. I really appreciate the perspective you share with us. Its nice to have some new food for thought! Love ur content! 🥰🥰🥰😁😁😁😁💚💙

so the big bang happened everywhere, and there is no center. But there must be a coordinates within our current universe which once contained the whole universe...

In order to find a center, you need to know the object being measured in its entirety. We can only see so far out,so until we can see the Universe as a whole it's a moot point

According to most people these days, especially people who are constantly taking selfies... THEY are the centre of the universe!!!

That's the best use of 'Not to scale' I've ever seen.

Thanks for sharing dr Becky 🌌

A slight error: the observable universe is about 93 billion light years in diameter (thus its radius is ~46.5 Gly, not 14 Gly. It's a common mistake made even by scientists sometimes. The universe has been expanding for almost 13.8 billion years so the light itself is traveling the expanse ...

She's doing a good job explaining things in a simplified way. Saves up lot of time for us.

Thanks for video keep going 🤠 greeting from Morocco

I love you, Dr. Becky. I was just thinking of this question the other day. Oh, and you sung the Galaxy Song! Eric Idle's masterpiece. You rock. Now, do a show about 'voids'. They always fascinate me. I'm a nascent sci-fi writer and I'm cramming a lot of info into my head to prepare!!

" The universe is a place where the centre is know where and the circumference is everywhere ."

The center of the universe is in your heart ❤

When I rolled in here I was prepared to refute your assertion that the universe does not have a center. You took the wind from my sails with your excellent presentation. Your analogies of the balloon and explosions helps me understand the universe more. One crazy thought that may be related is the inter-relationship of the universe and one-sided objects. Everyone here could make one in a minute or two and hold it in their hand- a true one sided object with no tricks involved. We are talking shapes and it seems a round universe may not be true and we may never know what shape the universe may be since we will never be able to observe or map it all. All the weird shapes in field of Topology may give us some ideas of what possible shapes the universe could be.

I learned astronomy from "The Galaxy Song" too!

Everything we know from quarks to galaxies have a center. Every type of atom has a center, ever type of star has a center. A sphere, a cube, a pyramid, they all have centers. So do their 2D counter parts, circles, squares, triangle... All have centers Your skull has a center, the Pacific Ocean has a center. the display you are looking at right now has a center. How do we know this? Because we can see it. We can't see the entire Universe, so obviously we can't locate a center. But we do have something called the chaos theory, which is actually a poor name for it, since it's not just a theory it's a fact. Why do the Bronchial tubes in our lungs branch out like that of a tree? The Chaos theory. Why does our solar system, or the moon system of Jupiter, share similarities with the structure of an atom? The Chaos theory Why does convergent evolution happen? Sure environmental factors, but that's still the chaos theory Because everything we know has a center, the chaos theory demands that the Universe has one as well. But the Universe has no end, no borders... How can there be a center to such a thing? If you think of the Universe as just a three dimensional entity, you could never locate it's center. You need to see the Universe in four dimensions, then map it in reverse. "So basically you typed all that just to say hit the rewind button?".... Yes But obviously that is beyond our capability to accomplish, or to even try to plot such an event. Let me put it this way, let's say we could only see the 10 closest starts to our solar system. How would we know we were located in a spiral arm of a galaxy that contained a 100 billion stars? How would we locate its center? That's what we are facing with the observable Universe, we see such a tiny fraction of what actually exists. So we can never locate the center of the Universe. However from all we know and all we see, and thanks to the Chaos Theory. We know the center exists. Incidentally... Just for the record. The Chaos Theory proves without a doubt that life exists elsewhere in the Universe. If life can spawn out of the chaotic formation of our solar system, then the Chaos Theory demands it happens elsewhere. If you made it all the way to this end.. Thank You 😉

The rate of expansion appears different in different areas. Perhaps this is because of the nature of the universal core and the time it takes for us to observe changes to it. A core would also likely be massless and possibly lack any emission of light.

You cant say we'll never know with such certainty. Perhaps in the future we find new techniques that allow us to study what is beyond the observable universe.

My mind is having a Big Bang trying to comprehend this

It must be difficult to date a cosmologist...they always need their space.

Basically we know very little.

The universe began as a single point and has been expanding ever since, it absolutely does have a center. However until we can locate the edges we can never find the center.

You are a great speaker wish we had more teachers like you.

I can't follow this (yet?). Sounds to me like: "Galactic movement is relative, so we can't tell where the center is, so we're going to claim there is no center."

You're such an excellent teacher. Even when I know the subject or question in your video title well enough to explain it to others already, I still learn from your videos.

Hi! First, you’re amazing. I just discovered your show on you tube. Space and physics fascinate me. It makes my head hurt but it fascinates me. Your balloon analogy helped a lot. I get that we don’t know the size and shape of the universe and the universe is constantly moving so I get that we can’t calculate the center. What I, and many lay-people, have trouble with is common sense tells us everything has a middle. Thought?

Thank you.

Any shape has a center.. We will just never know. And it probably changes.

That clears up one query of mine. I often wondered how we knew the universe was expanding, as galaxies would expand at the same percentage rate, as would solar systems, tape measures, the wavelength of radiation, indeed atoms themselves. Ok, so gravity negates the cosmological expansion within galaxies. But experiment has shown that the fine structure constant and other 'atomic properties ' have remained constant over the life of the observable universe. Is this because something balances out or negates expansion on the atomic scale? Or is it that we measure everything from the atomic scale and it's expansion hides everything up to the scale of galaxies?

One thing that always drives me crazy but you explain the reason why well.

I learnt something new here!

Thanks for that great video! I have a question though. I think I manage to understand why the big bang happened everywhere and not only at a given point. However, if the universe is finite and with borders, doesn't it make it having a center by definition? If it is finite, with border, there must be a point which is at equal distance from the every points of the border (if the universe is a 3D sphere). I totally see why there would be no center on an infinite universe or a finite univers without border, but I really can't understand a finite universe with borders having no center. Can someone please point out what I am missing? Thanks!

Your explanation of expanding space at the beginning and the '3d' balloon analogy is the best I've heard thus far. Your explanation of the observable universe being earth centered vs the entire universe having no defineable center is perfectly pragmatic. Many thanks.

In one of Carl Sagan's earlier TV projects, The Violent Universe, I laughed when Hoyle was described as a "cosmic anarchist." That will stick in my mind forever... LOL

Mind is blown thinking about this...

The universe "pearled out" very much like CO2 does in water when you lower the surrounding pressure. It happened pretty much in all places at the same time. Inflation doesn't necessarily need to have a center. It's just inflating from everywhere. And no, not everything is drifting apart. We've observed for long that certain elements within our galaxy also approach each other.

Sing us a song Dr Becky, sounds like you have a voice.

I have aleays enjoyed your enthusiasm, presentation style, and wealth of knowledge. Thank you from this creature in a complex universe.

Once you got to "the observable universe" part of the discussion, the "no centre" was immediately understandable to me.