The Copernican Principle: the foundation of ALL of cosmology

[@ronstallcup]

I'm glad the universe created Dr. Becky.

[@rachel_rexxx]

Her mum: _umm...I have a name_

[@oortcloud8078]

Her dad: _umm...I haven't a name_

[@andy2950]

A test tube : Er.....

[@oysteinsoreide4323]

We are all children of the universe. Enabled by violent events spreading heavy elements.

[@oortcloud8078]

We are all made of star stuff.

[@peteredwards2318]

Copernicus, seeing and saying what others dared not. What a hero! Edit to add: The thing that I've come to believe having been wowed by space science since I was a kid, is that Copernicus is right, our location in the universe isn't special, but only because EVERYWHERE in the universe is special, perculiar. At no two points in the universe are conditions precisely identical. No two solar systems are the exact same, or mirrors of one another. No two clouds of gas that form stellar nurseries, produce stars that are exact copies of one another, as to size, rotation speed, or trajectory through space. Its all special, and because it's all special, special is within the normal distribution.

[@juimymary9951]

That's a pretty good way of looking at it, though it is a philosophical stance rather than a scientific one. Which is welcome though :)

[@RHCole]

"no two solar systems"

[@BeeblebroxTheThird]

​@@juimymary9951One might argue science is philisophical 🙂

[@surendranmk5306]

You are exactly right, great thinking, one thing more you might have told us, the particles which make all these universe exactly identical altheway everywhere.

[@tiago.alegria.315]

Although everything is made of the same matter, and dark matter although not in the same state and circumstances

[@Test1-i9u]

Krikkit planet's inhabitants used to apply the Copernican principle. (a planet located in a dust cloud, where they thought to be alone in the universe). They did not like when they discovered that the principle did not work there. Their solution was not to change the principle, but rather to make it true again by destroying everything else :) (Douglas Adams, hitchhiker's guide to the Galaxy)

[@rustythecrown9317]

Whop.

[@mal2ksc]

Earthbound science has replicated their Someone Else's Problem field, but thus far has kept it confined to themselves.

[@artur-rdc]

Most places in the universe are dark, dead, empty and lifeless. I would say that makes this place pretty special.

[@BeeblebroxTheThird]

"Most" or "all"?

[@waynedarronwalls6468]

I would say more fortunate than special

[@samuela-aegisdottir]

The Copernicus principle is meant to be applied on larger scales.

[@oatlord]

But we don't know yet for sure if these places mentioned are dead. Life could be found to be floating around all over.

[@csh43166]

@@waynedarronwalls6468 I agree...

[@jorispattyn9690]

I love the enthusiasm with which you tell about these interesting, but difficult items, Professor!

[@Adiscretefirm]

Dr Becky is so good at her job I feel like I understand what she's talking about

[@mikea.p7319]

“There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.” So Albert Einstein said, anyone in my opinion who understands just a glimpse of the workings of this Universe, the Earth and life has to choose the latter, so yeah I reckon Earth is very special! 😉👍

[@chadbailey3623]

In 2017, I visited the Cathedral of Kraków, where Kopernik (Copernicus) did his work as canon.

[@oortcloud8078]

I thought the church fired him out of a cannon, for suggesting the earth's motion through space.

[@rustythecrown9317]

@@oortcloud8078 sounds like a church thing to do.

[@Valery0p5]

​@@oortcloud8078 well that's po(o)p shi-ence for you, there was no hostility towards his works in the beginning, it was only one century later when Galileo went meddling in politics by attaching the papacy that he ended up in house arrest (no execution btw)

[@richvandervecken3954]

Copernicus was not the first to propose the heliocentric model of our solar system. In around 270 BC a Greek Philosopher Aristarchus of Samos proposed a heliocentric model of our solar system. Aristotle argued against the heliocentric model being adopted because it used perfectly circular orbits and was less accurate at predicting the observed paths of known celestial bodies like the planets. Copernicus added smaller circular orbits to the planets around a central path the orbited the sun in the perfect circular orbit. What this epicycle did was brilliantly predict the elliptical orbits that the planets actually orbit the sun in. Johann Kepler was the first mathematician to recognize from the data collected by Tycho Brahe's staff over a 20 year period of recording the position of various celestial bodies that the planets were orbiting the sun in ellipitical paths. Kepler also identified that the planets accelerated as they traveled toward the sun and slowed down as they traveled away from the sun. There are people who claim that heliocentric model proposed by Aristarchus was inspired by a much earlier philosopher from India who had also written on the subject. This is very possible as Aristarchus did spend time in the port city of Alexandria that routinely confiscated all books onboard ships that docked in it's ports, kept the originals and gave copies back to the ship.

[@kylie_h1978]

Came to say the same, though even earlier, 5th century BC, there were Greek philosophers, Philolaus of Croton and Hicetas, who came up with the idea of the Earth being a sphere that orbited a central fire, the sun. Their works might have also influenced Aristarchus later writings.

[@AuroraCalifornica]

I did a research project on this subject! Copernicus even referenced Aristarchus originally!

[@mindbegone]

Thank you very much for giving you perspective on the cosmos. Nature dose beautiful things.

[@DannyJoh]

Not being exactly like the average, doesn't mean we're special. Rolling a 1 on a dice is as big chance as the other numbers, even though the average is 3.5. So the natural variation really makes sense to me.

[@perkytxgirl]

Isn’t it more of a general assumption than aprincipal? Finding out that earth is unusual or even unique would not break science it would just be statistically unlikely.

[@peterwilson8039]

The implication that is important is that the laws of physics are the same all over the universe. Obviously the core of the Sun would be very different than floating in a sea of nitrogen slush on the surface of Pluto. But what we do is believe that the exact same laws of physics apply in both places. Clearly we can't know that for sure, without first exploring every corner of the universe.

[@TomLeg]

People keep showing the CMB without discussing the extent of the variation. Finally someone (you) mentioned that it is 1/1000

[@deanbibb3680]

I love the t-shirt! My father Jack Bibb was a forest ranger here in WV, serving for 41 years including his time counted in the US Marines during the Korean War. I literally grew up with a Smokey Bear costume in iour shed and one day dad pulled me out of high school to wear it on a visit to the local kindergarten class.

[@jasonGamesMaster]

I grew up in Southern West Virginia (Mercer co). WV represent, lol

[@deanbibb3680]

@ awesime! I grew up in Ansted in Fayette County, I’ve been in Beckley since 2001.

[@jasonGamesMaster]

@deanbibb3680 nice! I got my acoustic guitar at a little shop in Beckley around 2000, lol. Moved to TN for college in 2001, but I still head up that way for family :D

[@MCsCreations]

Thanks, dr. Becky! 😊 Stay safe there with your family! 🖖😊

[@condorboss3339]

That seque into the Surf Shark ad was perfect.

[@mikeblake9761]

Science with Dr Becky is amazing

[@yosoyunapina]

As a layperson, the Copernican principle has struck me as being very much like Occam's razor. As in, it's a nice rule of thumb for what might be a safer guess when there are many unknowns, but obviously the simpler answer is not really _always_ the correct one, and obviously all conditions around Earth are not identical in _every minute detail_ to everywhere else. (That planet Earth is here but not also over there and there and there and there and also there in countless duplicate should be demonstration enough against the inviolability of the principle.) It bugs me how ideas in cosmology seem to so often be founded upon treating cosmology's figurative Occam's razor as an assumed infallible trusim. We have no rational basis to assume that local observations are universal, without evidence to support every individual case. Dark energy being ubiquitous implies nothing about any other condition.

[@kuksoolwonpearland]

Can you explain why prevailing understanding indicates the universe is expanding? If more distant galaxies are moving away faster than closer ones, why doesn’t that indicate that the universe was expanding faster in earlier eons and is not expanding as fast in more recent times?

[@wavydaveyparker]

You know I had to stop and think about that for a second, as it's a bit of a mind bending question. However, it's to do with the fact that when we look at distant galaxies, we're looking further back in time. We should expect the distant galaxies to be moving away faster, if the expansion rate is slowing, but we see the opposite. I hope that makes sense? But, I'll try and think of a better way to explain it later, if you're still interested. 😅

[@sciencerules281]

This is the first video I've watched of yours. Earned a subscribe, it seems like at a large scale the universe seems easier to observe and even comprehend while on the smaller scales the random fluctuations throw us for a loop. Kinda like things here on Earth are relatively simple until you get down to the quantum level then we're thrown for a loop. Funny how that happens.

[@SansBonita]

Since we’re talking about matter, I lean towards the idea of building a home from clay. You would be able to visit both the pit and the structure but that would require a larger underlying thing which is not out of the question.

[@eulermachado3968]

Commenting just for the algorithm. Yeah , coppernicus and anthropic principle. I loved how your video and PBS touched these themes at the same day ❤

[@RodrigoLobosChile]

Thanks for this video exposing a simple, straight forward, delightful but fundamental principle

[@WilliamCawley-g9k]

Been watching since she started her channel and I am still enjoying her show.

[@andy2950]

Who's "She" ? The cat's mother? 😊

[@PeterPrevos]

This principle is derived from esotericism and the Emerald Tablet, which states: "As above, so below". It was the first time the idea that there is no heaven and earth but one physical reality. Newton knew this document intimately well; he even translated it. The publisher of Copernicus also published the Emerald Tablet. So, in other words, our natural sciences are founded on esotericism.

[@Phelms]

"We can't move the earth, we are stuck in one place" We just haven't made a big enough rocket yet

[@Mr_Wheels74]

Normally I'd say music in the background of talking is a bad thing and a bit distracting because well it is (to me at least), BUT the way you've started doing it in just the intro is an interesting touch.

[@eljcd]

The Cosmological Principle, and the assumptions of isotropy and homogenity over whom the LCDM are built, were reasonable when there didn't exist enough observations of the Universes at large. But by now, there is evidence that Matter is concentrated in filament- like structures surrounded by ever growing voids. Even our galaxy is inside the KBC Void. Maybe These facts can be acomodated in LCDM adding more parameters or moving their goalposts, but I hope more Cosmologists get to work in Cosmologies that have in account the real shape of the Universes, like the T8mescape model.

[@plektosgaming]

Eventually these voids will grow such that many billions of years from now, we will see our local areas of space and nothing else - just darkness as everything is too far red-shifted. There has been some speculation that the early universe's physics operated in such a way that space expanded at a dramatically different rate and what we see is the current "metastable" set of physics that we operate in - like a bubble within a larger bubble ( though a massive one ). And that eventually physics will finally move to a "stable" version - which we may or may not be able to detect very well. It would still register as dark matter/mass, though. Some people have hypothesized that these voids are regions where this is already happening - miniature pockets of different space that we simply don't detect properly as the physics at work are different enough that we see "nothing", aside from a different rate of time and so on.

[@eddiegaltek]

I just had a thought listening to the bit about the expansion on the universe. If the more distant galaxies are receding faster than the nearer the galaxies this would equate to the galaxies we can see from further back in time receding faster then the ones we can see from more recent time. So, why doesn't that mean the universe expansion is slowing down rather than speeding up?

[@Harkmagic]

The best evidence of us being in a special place in the universe is that we exist and have zero evidence to support the existence of similar life in the universe.

[@kkjhn41]

We have zero evidence because we do not have the technology to obtain such evidence. Until we can travel to every part of the universe and look for such evidence one cannot say with any confidence or conviction that life exists only here making us special. Only hubris, vanity and arrogance can make the claim we are unique, alone and special.

[@dougaltolan3017]

Nahh, you just can't get your head around "astromomically big" or "virtually infinite"

[@gmotionedc5412]

If we are nothing special, then the universe is bursting with life. It’s over flowing from the abundance of life. Life is everywhere if we are not special.

[@dougaltolan3017]

Bursting, overflowing and abundance have special meanings when density is as sparse as the universe.

[@Raven-um2wf]

It may well be for all we can tell currently, time may tell. Or not, that's the fun part!

[@kidmohair8151]

the planet we inhabit is not in a "special" place. it is, however, in a particular place. one that leads us to make observations based upon the particular conditions that prevail in this particular place.

[@aresaurelian]

Let's go, kids! Explore.

[@ZeroInDaHouse]

The universe is maybe an infinite neural network of information that keeps recreating itself on ever smaller scales due to entropy. In essence one huge consciousness where entropy leads to emergent behaviour like self-repeating, self-awareness and finally love due to our connectedness to everything.

[@PeterBeckleyArt]

please tell me you're going to expand on what kind of considerations and things we have to take into account knowing that the Milky Way is in one of these rare voids!

[@AaronMoore-h6j]

I’m surprised you didn’t mention the Axis of Evil, especially since you’ve done a video on it and mention the CMB. I don’t have an opinion either way on it but it seems odd to leave out.

[@darthvirgin7157]

HINTS of this principle have already been considered all the way back to ANCIENT GREECE. Aristarchus of Samos actually hypothesized a HELIOCENTRIC model of the solar system almost TWO THOUSAND years BEFORE Galileo proved it with his telescopes. he even conjectured that the stars are also suns but are very distant from us. and his hypothesis wasn’t quite as controversial as it was during Galileo’s time. the biggest reason was showing parallax as there were no telescopes at that time.

[@ericlondon5731]

Since the most distant objects are moving faster than near space objects, that seems like the universe was expanding faster further back in time than it is now. The complete opposite of what I have ever heard.

[@JME1186]

I have nothing of value to add and apologize in advance. However I’d be remiss not to mention the first thought that pops in my head any time I hear Copernicus’ name. Family Guy skit featuring a couple Italian American men with a little Mafioso vibe, standing in line at a nightclub or restaurant. Some poor sap gets a bit too close or tries cutting in line and the one Mafioso guy says “Hey, ho, Copernicus; Why don’t ya navigate yourself to the back of tha line with ya shoes… and stand there with ya shirt”. It’s very random and hilarious

[@RaymondSwanson-u9y]

There's one thing about cosmology that has always bother me, and that's direction. Every direction we look leads straight back to the beginning of the universe. No matter what direction you pick, if you look deep enough, look far enough, you see the beginning. All directions lead back to the beginning. All of them. There is no sideways or forward, just behind. That's something cosmetology can't explain. Why can't we see what's in front of us? It's all behind us in spacetime. Even if by a few microseconds. Everything we experience has already passed us by. It's like we're in a mirror universe. Rear view only.

[@GenaTrius]

I think some day we'll find that there's something slightly unusual about our region of space that affects some readings or another, like how our ancestors found that nature only seems to abhor a vacuum because we're in a relatively high-pressure zone on Earth.

[@Steelrat1994]

I mean, the video basically says exactly that: we're in a supervoid, it affects our measurements and we have to account for that. Copernicum principle is not a universal law, just a wishy washy guideline like Occam's razor. Whether it holds or not depends on the scale at which you're looking at the universe.

[@csh43166]

"Special" is generally a highly subjective term, even in science. But this is definitely an interesting thought exercise!

[@andersjjensen]

That the KBC void is nearly six time the radius of Boötes void, and that we are somewhat near the center of it, should not be treated with hand-wavy gestures. Gravity travels at the speed of light minus the speed at which space expands, and we are still not sure if the expansion of space is gravity related. So being in the center of a rather "gravity deficient" region, which is surrounded by clusters and super clusters, could very well be the perfect spot to observe from.

[@mattslaboratory5996]

Science doesn't prove things; it collects evidence that supports things (or not). See the Raven paradox. It seems reasonable to me that we could be in a place that makes our observations inaccurate somehow: some fog or tilt to spacetime that we aren't aware of. Great video as usual. The way Dr B lays out her main points, and her choice of them, always makes the subject clear and memorable. She's got a knack. Probably got it from a professor she had.

[@RyO-lt1ui]

Do you know what I love about Thursdays? Dr Becky Smethurst and PBS Spacetime publish videos about the same time and it's been consistent for such a long time!

[@nurmr]

1:52 Siri activating with the word "theory" 🙂

[@brainmuffins6052]

My usual response is: “Then tell me where in the universe the Earth *should* be in order for it to be special?” You can’t have an isotropic & homogenous universe and then have 1 special place. We know it’s not the center, since there is no center to the universe. What we are really talking about is human beings. Are we special? Until we can prove otherwise, then yes we are, but don’t hold your breath. Everything mystifying is special until the truth is revealed, then it is mundane. It will be the act of finding intelligent non-human life that answers the special question once and for all. And we don’t know that yet… until then… you are special. You, among the 7 billion other special people…. 🙂 Is it that important to be special anyway?

[@SrenkZee]

Pleasure to see you again 😊

[@maarten.dejong]

Heliocentrism, in the West, was widely accepted in the Greco-Roman civilizations. It took a while, after Copernicus, to be fully adopted.

[@tiago.alegria.315]

Thanks for sharing

[@BartdeBoisblanc]

6:40 Dr. Becky one thing is true we haven't found life on a planet other than Earth yet.

[@luizbotelho1908]

You are apparently discussing a Axiomatic Principle of Theoretical Physics (in the mathematical sense): The existence of "Universal" Inertial Systems .

[@Johncornwell103]

So what happens to cosmology if a definitive study disapproves this principal? Like they discover that the void we are in is actually bigger than we thought? Or what if the observation in regards to the Axis of Evil becomes even more drastic and it violates homogeny and isotropic principles?

[@EdmondHubble]

great vid!

[@PaulBrunt]

The Copernican principle is more then just place. Our location isn’t special, yet all theories in cosmology imply that it is special in time. Why should we not apply the same principle to time? Why should our time be special? Just as we assume our place isn’t special, we can assume our time isn’t special either. For some reason, we believe our place isn’t special, but our time is-why? If an idea works in one dimension, isn’t it logical to assume it works in others as well? The universe makes a lot more sense if we remove the assumption that our time is special.

[@oluf999]

If Earth orbits the Sun once a year at a distance of about 8 light minutes then that would create an acceleration of about 0.006 m/s^2 (a=v^2/r). If that acceleration could be measured wouldn't that prove that Earth is moving and therefore not special?

[@wavydaveyparker]

Not necessarily, you've made some pretty big assumptions there, and Einstein would probably still tell you that it's impossible to determine whether you're at rest in an inertial reference frame, or it's the sun at rest in an inertial reference frame. Sorry, if that sounded defeatist, but that's the problem with relative motion and Special Relativity. The actual problem was answered by the tidal motion and confirmed by the annual Parallax of distant stars. Nice idea though. Thanks

[@oluf999]

@@wavydaveyparker Ok I have not really understood the claim that motion is relative but acceleration is absolute. Is motion that creates acceleration relative or absolute? Another example is Earths rotation once a day. a=v^2/r gives 0.03 m/s^2 at the Equator and the effect can be seen by Earth is wider at the Equator than a perfect sphere would be (about 0.3%). Also that the measured gravity at the Equator is less than at the poles and that the difference fits with the 0.03 m/s^2. Is Earths rotation relative or absolute?

[@SerendipFromOz]

You are quite right, the earth is indeed moving with respect to "the universe", because it moves around the sun, the sun moves around the centre of the Milky Way and the Milky Way moves with respect to the surrounding galaxies. But this doesn't make it special. A beautiful signature of this motion is that it leaves an imprint on how we see the cosmic microwave background. Google "cosmic microwave background dipole" to find out more

[@wavydaveyparker]

Hey there, have we spoken before? You know I have a comment section, where I've discussed this at length right, and you'd be more than welcome to participate. 🤓 Anyway, all motion is relative, regardless of the frame of reference. There are no absolutes. That was Einstein's breakthrough, there is no privileged frame of rest anywhere in the universe. Everything is accelerating. And orbits, revolving motion or rotating motion is just a special case of accelerated motion. You're calculations are reasonable accurate, but do you realise that when you use (v²/r) you're actually calculating the inertial centrifugal acceleration. The centripetal acceleration is gravity and it's equation is (GM/R²). Drop by my cartoon sometime and we can delve a little deeper into to the mystery of the Earth's motion through space. Thanks

[@zoastro]

It's like trying to take a picture of the food that you ordered to prove that you didn't receive it.

[@TemperedWambat]

Even if the copernican principle is wrong. You can take the instrumentalists route and argue that cosmology is just one of many tools we have to understand the universe around us.

[@nachtkap]

No pips =(. Also thx choosing something non white as background for papers. Makes for much better viewing in low light and the dark.

[@sw-gs]

I always thought that Copernicus only proved that Earth circles arround the Sun, yet he still followed Catholic Church doctrine that states that Earth is center of universe. It was Galileo Galilei who proved otherwise by comparing night sky during seasons when he noticed stars drifting (which we now know that were planets) and that theory was why Catholic Church prosecuted him.

[@craigmooring2091]

As I recall, there were those among the ancients who called the geocentric model into question, but of course, there was not the technology to prove or disprove any model of cosmology at that time. Ptolemy discussed this matter in his Almagest, but ended by saying he and his model were mainly trying to "save the appearances", i.e. provide a mathematical model to accurately and precisely describe and predict the perceived motions of the "planets" (bodies that wandered against the background of the "sphere of the fixed stars"). So, I don't think it is quite accurate to say that Copernicus was the first to demote the Earth from the center. It wasn't even fully accepted in his time, as Tycho Brahe's compromise model had some traction for a while. It was only when Kepler, who inherited access to Tycho's records of data that were unrivalled in precision, realized that the perfection of Ptolemy's circles and epicycles (circles moving along on other circles) was not only cumbersome but also unable to match the precision and accuracy of their sister conic sections (ellipses) in describing the motion of the planets, that the Copernican model was able to stick. Especially as it harmonized with Newtons work on gravitation and provided an understanding of the physical cause of the phenomena. In Aristotle's terms, it seems to me, Ptolemy's model(s) provided only a formal cause for the appearances (circular motion); Kepler and Newton provided not only a formal cause (elliptical motion, or in the case of Oumuamua, hyperbolic motion) but a material cause (gravity acting on mass).

[@davidtatro7457]

There are nearly an infinite number of ways in which the earth and its place in the cosmos might be special. Not only can we not eliminate all of those possibilities with observation, we cannot even know how many of them we don't know. Which is by no means to say that we are special, but the question is unfortunately relegated to the field of philosophy.

[@masterxyr]

hey hey hey! the milky way and our little solar system are special in my heart :))

[@ronhudson3730]

What would be special about being in a special place in the universe? What advantages would that confer? We have not detected, to my knowledge, any non-natural, energy transmissions from anywhere else we can observe in the universe. To our knowledge, no other sentient, self-aware and conscious beings exist elsewhere in the universe - not to say that there aren't or that there can't be, just that we have no current evidence for them. Until proven otherwise, we are not in a special place but we and our planet are by the definition of apparently being unique, "special".

[@cav89-]

The ‘specialness’ would refer to the universality of physical phenomena and their behavior, or rather, their non-universality. If the earth, or our star system, or our galaxy, is “special”, it might be that the way reality - the laws of physics - behaves here is different than the way it does in other places.

[@jeffspaulding9834]

See, this is why I hate it when people use the word "special" in cases like this. "Special" is a human judgement. It exists only in the mind. It's kind of like trying to find a particle of justice or an atom of beauty. "Unusual" would be a better term. To use Adam Douglas' example, if Earth was in the middle of a dust cloud and we couldn't see the stars, we'd be in a situation where the Copernican Principle wouldn't hold.

[@ronhudson3730]

@@cav89- And that is meaningful, how?

[@joen0411]

My problem is I still can’t wrap my head around the fact no one can tell where the center is. I’ve heard multiple explanations and none of them make sense to me. The inflating balloon example is the most annoying because I can easily tell where the center of a balloon is. If the universe stopped expanding but we were unable to see all of it because it’s too big. Then I could understand why we can’t figure out the center. But since it is expanding, it has to all be moving away from the center. Even if the center is too far away to see, we should still be able to figure out the general direction of where it is. But no one can and I can’t comprehend why.

[@AntavasSpeaks]

Consider a number line of only positive whole numbers. Where is the center of the number line?

[@jeffspaulding9834]

The balloon analogy is often not worded quite right because it's difficult to imagine. It's not "space is like a giant balloon." It's more like "every point in space is a balloon, and they're all inflating at the same time." If you place a mark on two balloons, the speed at which they move apart is the speed of inflation of all the balloons between the two points. Mark two balloons that are farther apart and they'll move away from each other faster. All the known forces are orders of magnitude stronger than this effect, so we don't see it between things that are gravitationally bound (like Andromeda).

[@jasonGamesMaster]

So, your second thought was almost right. The only difference is that it's not expanding from the center, but instead *new space is forming randomly in between existing places,* thus expansion in all directions without a center. So, in just a 2 dimensional example, if you had 1 point, then added another, it would be to the right or left. A second new point could be in the middle or on either side. Each new point is somewhere in among all of them, but it's impossible to guess where, and very soon it's impossible to really even guess where that original point is. This is, basically, what dark energy is. A placeholder for the mechanism that causes all the plank length "new space" bubbling up.

[@sergey9986]

The balloon example is fairly straightforward for you, because you are 3-dimensional. If you were 2D, you would wonder why your cup of tea is moving away from you. If you were a 4D person, you might as well see the center of this "4D sphere" or might not at all if the 3D space just continues forever just like a 2D plain in 3D space does. We do not know the exact curvature of our space at the moment. From the current measurements it looks fairly flat, but you never know.

[@jasonGamesMaster]

@jeffspaulding9834 yeah, that's a good clarification. I never quite understood that analogy, and I do get the idea, lol. That is a good way of thinking of it, now that I understand what it's saying. Add the idea that we can't see the edges because they are over the horizon and that's a really solid analogy, honestly.

[@Radarcb329]

We are special just because we exist.

[@custossecretus5737]

I wonder if the cosmological web could tell us about the expansion of space. Surely the voids would be bigger the further away they are, because they are expanding faster.

[@specialnewb9821]

We are the only life. And since there is no center, until we know different we are the center.

[@SchumakerFamily]

Well - there is the Anthropic Principle that says we must be at a time and location that allows for the evolution of technological life. Otherwise we could never make these observations. For example, the universe can not be too young. We also cannot be too close to very energetic events like supernovas.

[@plektosgaming]

I'm a big fan of the idea that the universe is not homogenous as it fixes a lot of things with our current models. WHY is because recent evidence shows that time operates faster in those voids, meaning that they are expanding and in effect slowly corralling us into tighter areas and clumps over time ( since time flows slightly slower here ). Basically we're in a room with several large expanding balloons. How far will they expand? So are we "homogenous"? Barely so, and likely to not remain that way for very long. Maybe a few billion years?

[@DM-dn7rf]

The thinking at the time of Copernicus was that by removing the Earth from the center of the Universe it was considered a promotion into the heavens. Hell was at the very center, then earth and above all the heavens. So it was not considered as humbling us but exalting us.The height of arrogance.

[@michaelbourrell2693]

Our place in the universe seems pretty special to me.

[@andy2950]

I see what you did there......... 😊

[@geoffreywilliams9324]

Yes indeed the universe has to be the same age everywhere. This has some profound implications . .

[@keithrosenberg5486]

So far Earth appears to >be< a special place in the universe, being populated with life and all.

[@christopherlperezcruz1507]

I don't understand why we can't traingulate the location of the big bang. Say our area of space is a baseball field and we are at the pitchers mound and we are accelerating away from home plate. 2b will move away from us at the same speed home plate is but 1st base won't it should move slower if it is itself moving away from home plate at the same speed. Not only that but 1st base will move away from 2nd base at the same speed it moves from us and we can cancel out that movement to determine the perpendicular speed and figure out what angle its moving at relative to us and locate the big bang at the intersection created. Why not?

[@tinathelasttwenty1249]

Question: Are we evolving into a Singularity??? Dr Becky is the best ❤

[@JONSEY101]

Hi Dr Becky. I have two questions related to what was mentioned in the video. Firstly, if our solar system was in space but not in a galaxy, is it possible that we would still be here as we are today? Assuming we are still at the correct distance from the sun and that our planets still at the same distance etc. The other question is have relates to the expansion of space. As we look out into the universe, we are looking further and further back in time, due to time dilation correct so far? Also as we look further out into space, we see what seems to be, space moving away faster and faster. Am I right here? So Assuming those things are correct, wouldn't it suggest then that as we look further out into space, seeing space moving away from us faster and faster, that we are seeing space as it once was further and further back in time? If so, then wouldn't we have to reverse the results showing that space is, in fact, slowing down in its size over time? It would make sense considering that there was a big bang at the beginning of time where space expands outwards. Fast at the beginning and slowing over time, perhaps due to matter and the Gravity related to it. Just a thought!, lol! 😂 A great video as always. Take care! ❤

[@sdmarlow3926]

Well... I don't see how a uniform CMB doesn't count against the Copernican Principle, where we would expect to be closer to one edge than another.

[@peterolekvint3214]

Earth is special because it is where we are. If there is a earth somewhere else, it is without continents because the ocean is too deep.

[@jimmeade2976]

Question for Dr Becky: If everything in the universe is moving away from us at the Hubble Constant velocity, no mater which direction we look, doesn't that imply that we are at the center and everything is expanding away from us?

[@YayComity]

And I suspect more "demotions" are in our future, perhaps with quantum foundations. Protecting that which we think makes us special is a powerful drive, and we'll go to extreme lengths to protect for example our over-broad concept of our free will. Could quantum superposition be the modern analogy to epicycles? Who knows, but I do suspect most physicists now agree that the Copenhagen Interpretation, in particular that decoherence is caused by conscious observation, was among our greatest human conceits. Copernicus deserves credit for being ahead of his time, but it's science itself that moves forward and dispels biases. To have one's name associated with the leaping of a scientific hurdle has to be among the greatest honors!

[@BillMSmith]

As I was watching it occurred to me that you are bucking an all too common trend among science (and other fields) communicators. Your videos are getting better. You've changed up how you present your material and I feel it's a bit crisper. I know there's a fair bit of work getting these out regularly, thanks for staying with it and for doing such an excellent job.

[@stuartschaffner9744]

As far as I can understand, we have a huge amount of evidence that points toward intelligent life capable of doing astrophysical measurements being much more likely to exist in regions of space which are dense but not too dense. So, astrophysical data is most likely to be taken somewhere near the edge of a void. Didn't you even say that a paper recently pointed this out? However, doesn't other data point to the idea that at some larger scale the voids stop getting larger? The cosmic background seems to show that. I also remember the idea being bandied about that the matter just after the Big Bang was at least roughly in thermal equilibrium. That argues strongly for uniformity on the largest scales. It seems to me that most likely the universe looks like a sponge. We are extremely likely to be observing the structure of the sponge from the edge of one of the cell walls.

[@chrisw1462]

"..even though we are in the KBC void, it is still representative of the universe as a hole." (Purposely mis-heard for the fun of it)😀

[@zhinjio]

How far away from our current location do we need to get before an observation could be considered relevant to a real proof? How many of that type of observation would it take before it considered a large enough sample size for proof?

[@DukeONerds]

💡 "Okay, I’ve got a dumb question, but Dr. Becky always says to challenge ideas, so here it goes. You teach us about the Copernican Principle-that we’re not in a special place in the universe. But what if we’re still thinking too locally? Not just in space, but in physics itself? We assume mass is an intrinsic property, but what if it’s actually emergent-stabilizing at resonance points in a deeper quantum structure? Just like how sound waves hold objects in standing wave nodes, could mass itself be a stable resonance node rather than a fundamental property? If that’s the case, maybe the Higgs boson isn’t ‘lighter than it should be’-maybe it’s just the first visible standing wave in a larger framework. Instead of looking for a hidden force, should we be looking at resonance conditions that define where mass can even exist? Mathematically, if mass is locked by resonance, then: m_higgs = m_planck × f_res Where: ✅ m_higgs = 125 GeV (observed Higgs mass) ✅ m_planck ≈ 10¹⁹ GeV (Planck mass) ✅ f_res = Resonance factor stabilizing Higgs mass I don’t know-I’m just a nerd trying to keep up. Does this hold weight? ORMAS?

[@sillyshitt]

Shouldn't it be: We can't prove the Copernican principle YET? Once we leave earth and the solar system and perhaps the Galaxy, one day, then we can prove or disprove it right? Or am I missing something?

[@primoroy]

I paused the video at the map of voids near the end. Where is the KBC void? It's not on this map!

[@Valdagast]

I wonder if our universe is typical.

[@Dak3]

We are in a special place, the center 😊

[@MercuryIsHg]

You could just call it an AXIOM. Welcome to Mathematics!! As usual a great episode, thank you. PS isn't there some thinking that we're in a special place in our galaxy, namely the galactic habitable zone?

[@edgeeffect]

We're massively short on data at the moment.... massively short on data.... but, for now, Biology says "ya boo sucks" to the Copnican Principle.

[@bananabourbonaenima]

Where does this KBC void stand in relation to the 'end of greatness' scale?

[@brad.fuller]

is it ricky gervais who says we aren't "special" but we are "lucky" (or words to that effect?)

[@rickseiden1]

Dr. Becky, not including your own works, what are the three most exciting discoveries/papers you've seen in your career?

[@Zuringa]

I'm confused. If everything is moving away from us in every direction, that can only mean we are in the middle, surely? If we can see the cosmic microwave background the same in all directions, again, we have to be in the middle, right?

[@ehsnils]

Today "The Slow Mo Guys" published a video that seems like it re-creates the mass distribution of the universe.

[@basildaoust2821]

I may have asked this before because you say everything is moving away from everything else, then how is it that Galaxies that are moving away are also colliding with other galaxies since everything is moving away Colisions should not happen or you're not actually telling the truth about things because that makes it easier, no it doesn't it makes me wonder if you even know the difference from away and together, or up and down being the same. I'm glad I never tried to learn astronomy back when I was in university because I think my head would have exploded. Kind of like our anthropology class where every person in the class called out the professor a liar and he was like look I know I'm right so just believe me, whatever.

[@grizzlyponcho]

@drbecky Genuine question. So, we need to make observations from other places to prove the Copernican principle. But aren't we always moving? Earth round the Sun, Sun round the Milky way etc. By that logic have we ever made the same observation twice?

[@johnattwell9431]

Love your videos! I have a question about 3D maps of the universe. When plotting the locations of everything out there, do we take into account the fact that the light we get from these objects took different lengths of time to reach us? Things aren’t where they appear to be. When we create a 3D map, is it based on where things appear to be or do we calculate where each object has moved to since it sent its light signal to us? If an object is 500 million light years away, it’s had 500 million years to move to another location. I love looking up at the night sky and being amazed that, in a way, I’m looking at an illusion. The patterns of light that I see do not accurately reflect where everything currently is; rather it’s a complicated pattern of lights that were each sent at varying times in cosmological history that are just reaching us now.