What Is The Shape of Space? (ft. PhD Comics) 

Lucas Meneses lmao

Well I mean technically, don't they have that space dome thing?

lol. Too true.

Bold of you to assume flat earthers would watch this video

@@pblpbl3122 You never know.

Dalriad that's a good question. Let's get this up there so Henry can see

yea thats a very good question

+

Exact same question came to me. #FollowupVid

Dalriad This is what happens when u try to explain something complicated without math in 3 minutes video.

Perfectly balanced +- 0.004. So not really perfectly.

Reddit moment Edit: Thanks for the gold kind stranger!

*Are

Thats assumimg everything is finite

thats why thanos is never wrong

Mmm. Pringles.

This makes me want to eat a black hole

Finally, someone who gets it.

You're God damn right! :D

He may have used some different terms to make more sense and to not entangle things up...

-science discussions in future... :d

Incredibly underrated comment. Hats off to you, sir!

Julius Javellana Duuuuude, you're so on to something NASA lies. Jay slash Kay

Or just have a lot of screenshot material.

Wait a minute, are you talking about AtomZadra?

azdgariarada lol

Wouldn't that be round spacers?

azdgariarada I am a potato spacer

SuperNuclearBoss 1337 Count me in

not planet flat as you would think, but space is flat, not the objects. But ha! And Columbus made my birth possible, so I owe it to a murderer

Holy sheet

omg yes!

ILLUSION 100

Yup

Justin Y clone

At least you haven’t give yourself whiplash trying to do one. There’s no coming back when even a doctor in the ER has laughed at how you got hurt haha

I just want this to be seen cause I know no 1 will see my actual comment in a like a year Have u seen those videos when they put a bowling bowl on a round sheet and smaller round objects if space is flat u cannot go under anything other rise u would go under space itself unless we think of it as a graph with 3d objects instead of 2d shapes the 3d objects can look as far as I want them to look

Wow u so stupid. The universe can’t cartwheel. Smh...

Roboblade604 Yes they’re thicc

But i think space is circle because if you look all the stars and planets are round. Even galaxies are round

Galaxies and planets are round, because gravity, shape of the universe has nothing to do with it... It's like saying that your house is made out of bricks, so your entire house is shaped like a brick. (Sometimes it's true, but you get the point)

are you implying this universe is fake

he is implying we are in a simulation.

Yes. That's exactly what I think.

I guess that's why the calculations were done from data obtained just after the big bang. The universe had just started expanding at that point of time.

That’s ... not how it works

Akash Raj - Yeah, it doesn't work like that at all, all matter from the big bang remains within our cosmic horizon or has past over our cosmic horizon over time. We say that all matter was concentrated to a single point only because we have calculated that BACKWARDS from space we observe today. There is no reason to believe space was not larger than a point at the moment of the big bang and that the big bang occurred everywhere with the space simply forever beyond our cosmic horizon.

@@callumscott953 Cant we see `just` after the big bang by looking 13.8 billion lightyears away? That's how we know about the cosmic background radiation and using trianulatiom we figured out the univers is flat (as stated in the video)

Yunpeng Liu That’s an interesting question. I think the answer may be no. If you consider the tools which we have on earth, which is a curved surface where we exist and seems like a reasonably analogous to living in a curved universe, then you can see that the tools which we have are able to measure the curvature of the earth. If you want a way that you can test that at home, take a globe and choose any three points on the globe. If you draw the shortest line between each of the points and create a triangle, then you can use a protractor and measure the internal angles and sum them in the same way shown in the video. While an impractical method for us to use on the earth, it should still scale if you get creative.

@@joshuareich580 Yes and you are right, but only in limited cases, which in your example is measuring 2D using 3D tool. Imagine you only have a perfectly flat protractor with mathematically 0 meter thickness and it only dwells on our earth surface which also has height of perfect 0. Then you can only have a "curved tool" as so to speak since the hosting space is curved. Would you know that the three angles together are more than 180 degrees? I guess not, because a 46 degree in 3D matches 46 degree angle perfectly in 2D but your tool reads 45 degree. Our world is exactly in that situation. We are using 3D to measure 3D, but we can only see the curvature when we jump to 4D. Hope I articulated well.

@@suwuliu5232 The way we measure curvature is by looking up into the sky, at the Cosmic Microwave Background radiation. In other words, we measure how the universe was in the PAST. Thus, we know that any possible limitation of measuring curvature due to being "in" the curvature will not affect our ability to calculate whether or not the space we live in is curved.

@@suwuliu5232 It is perhaps hard to visualise but we can in fact measure curvature without worrying about our tools being too curved. The usual way to explain this is using geodesics and triangles but it is hard to see why this avoids the problem you describe. We can solve this by thinking a little more mathematically though. The Gaussian curvature of a surface is intrinsic meaning it depends only on the surface itself and not on any larger space we embed the surface into. Similarly for any "pseudo-Riemannian" manifold (such as space-time) we can define an appropriate idea of curvature that depends on the "pseudo-Riemannian" metric. Put simply, this metric is how we measure angles on the manifold and it is a infinitesimal tool (that is, it acts on the tangent space, which is flat). TL;DR: We measure angles on a flat space tangent to the manifold and so the tools don't have to be curved.

Holy SHIT !!! NASA should Phone you

*more hydrogens made* Space: Suck it Matt

Some one can please answer

@@ireallylikeclouds989 you are sayng that hydrogen are created with space?

@@educn6830 no that would defy the law of energy/mass conservation

@@MattFyrm thank you

It's not really the matter density that's relevant; it's just easier to understand, given that we're made of matter. What's relevant is the energy density, which includes matter, radiation, dark matter, and dark energy. And as the universe has expanded, it has come to be dominated by dark energy. That's kept the energy density constant.

The universe expands with the matter, which is part of the universe, so the density is the same

I don't think that's what is being portrayed in the video. I think the video's definition of expansion is extension, as in the dimensions of space are growing. This is in contrast to a stretch, where the matter inside space would also "expand", but I don't think this is what was meant in the video.

It's not the density that decides the curvature. What was used in this video with 4, 5, or 6 atoms was an example. Basically what it is is if there was 20% more or less matter in the universe the curvature would be different. Honestly using the example they did just causes confusion.

Offstar1029 didn't he give a density though? 4 5 or 6 atoms per cubic meter

Can i have uhhhhhh *boneless* space and uhhhh two liter of time? Said the universe to god

Joel The Process Embiid *S P A C E I S J U S T B O N E L E S S S P A G H E T I*

Joel The Process Embiid *Boundless

It's just a stupid meme he meant to say that

Space is just boneless matter

Daniele Daniele was talking about the dots in the crossections tbh

The whole video is littered with illusions. You can't draw 3-dimensional objects on a 2d paper

I've seen both. :P

The lines are actually slightly curved. Since the screen is pixellated, you can see when the lines move up or down by one pixel.

Me

No, it's flat sadly :(

With that curvature ;)

Nah, it's flat cuz flat is justice

You're fucking stupid. They just said it was flat. This comment would be funny if it was using double irony which only stretches the joke. I'm so fucking mad

Something can be "thick" and "flat" at the same time

Is the clein bottle the 4d shape in your profile pic

@@Q__22 It is, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JBB-1MenYiE.html

You know you're a fuckin nerd when you're hyped to see a klein bottle comment

Reza Madankan Exactly.

Reza Madankan can you explain more because i can't understand

Reza Madankan which doesn't really mean anything, since the universe doesn't necessarily end at the edge of our observation. Who's to say we won't start getting light from far more matter out there, or even far less than we were expecting?

Flat means 2 D and anything with thickness or depth is not flat you stupid fucks. If you doubt me look up the word flat in a official Webster’s dictionary. You stupid fucks are like the uneducated people in the dark ages who thought the earth was flat. In 700 years people will laugh at stupid mother fuckers who thought the universe was flat. DO YOU UNDERSTAND YOU GOD DAM NEANDERTHAL?????

but what is a triangle? how do we know it's a triangle?

Eugene

Feynstein 100 Eugene!!! Woop! And PBS is amazing, too. Love them all!

Feynstein 100 mathologer too

SHOOKETH!

And earth

@The main cause of warps in all of reality you just turned the frogs gay

@@terner1234 *flat earther's brains

And the earth

that's what I was thinking xD

Yep

shaind god fucking damnit

Scientists and mathematicians say the geometry of the universe is flat, what are you, a science denier?

But it's NOT a hyperspace potato...... :(

No one knows how big is space or what shape is space

Pandavap I love your profile pic |-/

Pandavap A POTATO!

So the milky way could be a french fry ?

Doesn't have to be 3D, there could be more spacial dimensions out there that we just cannot even fathom, but regardless of the amount of dimensions, yes, flat as in no curves.

Chicken Of the Cave I thought matters interference with space created 3D

no this video says its flat like the earth but in reality a better explanation would be: Space = game water physics

Niels Rasmussen He's talking about curves with respect to the path of an undisrupted object. It would actually be counter intuitive to think that an object could essentially accelerate without an external force being applied to it, so we are essentially taught this principle from a very early stage in physics studies. The implications of space curvature are very interesting though. Imagine if you could permanently change an attribute of a finite region space so that the trajectory of objects passing through it is always predetermined.

It's flat on average, but local curves in space time exist everywhere there is gravity.

NON SEQUITUR IS PINEAPPLE

Goddammit Konata, you're like 30 y/o now, get over it already

Jose Perez In all the other universes Oppai is truth

Lolicon is my thing

Lel

Answer: Time is depicted on *CURVATURE, BOI!* in these lines of space’s expanse. SPACE is growing cuz particles are spreading. Since PARTICLES are spherical(perfect or not), the Earth. IS. ROUND. And so’s your head, get over it already!

Earth is obviously flat

Don't flat earthers believe that the earth is also a disk? Wouldn't the same reasoning fallacy apply for a disk as it would for a sphere? :P

I mean the Earth can be flat relitive to a higher dimension right? Nothing like the current flat earth model but *shrug*

I commented the exact same comment thinking "this is pretty funny, i bet no one said this" well i was wrong, so wrong.

60 Second Success Great Channel keep up the great work!

If space is potato shaped then it is not hyperbolic. One is positive curvature and the other is negative.

+Martin D A hyperbolic potato as in a Pringle

They're called books. Try it sometime.

60 Second Success Am I an unhyperbolic universe then? :D

city is my solar system

Universe is my country

Lucas Oliveira Saintrain potato is my life

galaxy is my continent

Space is my brain.

you watch phineas and ferb too! man, we're busted

I love when Doof, was spelled Doof

Ferb is braining

It's expanding internally. There is no outside to expand into. It's not like a balloon filling up, it's like the surface of a balloon stretching. If you draw two dots on a balloon and inflate it, the distance between the dots increases, but it's an increase in the internal distance of the balloon surface, not an increase into something.

@@Merennulli I don't think my mind is capable of understanding how something can stretch and be finite and not have something outside of it

Well, duh! If you think about Earth and the rest of the cosmos as the result of one big fart [the big bang] you'll see objective, irrefutable evidence that all celestial bodies our teachers have told us are round, in actuality, are flat! Why? Because "flatulence" has the word "flat" in it, obviously. It all makes sense, the damn government lied to us all!

Delta40 😂

If matter bends the Universe, then it can bend Earth too! *Mind blown*

shut up rick!

Still better than "who's watching this in 2017"…

Accepted as a plausible theory. I understand what you mean but it's hard to explain everything in 3 min. Also the "fuzzy part" before inflation is still difficult to model.

I guess you could say this video is **puts on sunglasses** flat out wrong YYYYYYYEEEEEEEEAAAAAAAAAAAHHHH I got too much sun today. Don't mind me.

Inflation is an as of yet unproven hypothesis. To claim that it is fact or the correct answer is putting the cart before the horse. There are also several other hypotheses that match what we know thus far and as such are equally likely. They are also exclusionary. We need more observation and experimentation before we can build a sound theory for the flatness or expansion problem.

because space is fake and the earth is flat

I thought Inflation explained why the universe was uniform in density. I don't think it explains why the shape of spacetime is flat. You could have a inflationary uniform-density universe with a bit more energy, and it would have positive curvature.

It actually could be. But then the cosmic hyper-potato would have to be so large that we cannot tell

No, this is Technoblade's Potato Deity

hornetluca if at the end of this universe was another universe wouldn't it just be the same universe but longer

Octillerysnacker , mind blowing

If the universe is expanding faster than light, in the edge because of time dialation, time is "frozen". And no matter how fast you go you can't go faster than the edge, your time would slow down. In the edge of the universe, it's like no time has passed since the big bang.

The end of space is unobservable -- light beyond the horizon will never reach our planet or our galaxy (since all matter is accelerating away from us)... So for all intents and purposes, it doesn't matter whether there is an end. Kinda beautiful if you think about it.

hornetluca asking questions there might never be answers to

Vark321 keyword: "theory"

Actually it is the hypothesis of inflation. There are many competing hypotheses about the early universe and how to explain what we see and why. We need more evidence before any of these can be a testable and predictable theory. When speaking in science it is only correct to use the scientific definitions for theory and hypothesis instead of the colloquial ones.

Andrea Teal Not really. Theory in science means it has significant backing based on observation and repeated experimentation. Scientific laws are theories which have undergone so much experimentation under so many different circumstances that they are now widely held to be true, and would require extraordinary evidence to disprove.

+AvalancheofNeed Sorry but that is not the definition of a scientific law. Scientific laws are expressed as mathematical formulas that describe how a phenomenon behaves. They do not attempt to explain any mechanism, just what is observed. They basically only state "this is happening and it can be described with this formula". For example, the Law of Gravity is not the same thing as the Theory of Gravity. en.wikipedia.org/wiki/Scientific_law

In astrophysics inflation is considered a theory: en.wikipedia.org/wiki/Inflation_(cosmology)

well, this is named "minutephysics" for a reason

That's why they say 'it seems to be', we may never know for sure. I mean we know that locally it's curved, also there is that Great Attractor drawing entire galaxies towards itself, so terms like local are on a whole different scale in spacetime. Who knows, maybe things work the other way around, and our universe "wants" to flatten, and that's the reason of the apparent perfect density, and not just some cosmic coincidence. Also, there is a chance that we got the wrong idea of something, did the wrong calculations based on that idea, and a lot of things we know might be simply wrong. Or maybe we are on the right track, but miss some crucial information. There is a whole slew of possibilities, luckily science is relentless.

because perfect balance would be a coincidence?

BakedBeans that doesnt seem cleverly. What a coincidence (!) That makes happen all life. And in this life only human can think on everything. There must be something we dont want to understand. We have to make an effort to understand the Real.

@@seyyidhansaroglu We are not basing off the coincidence as a 'mere' coincidence. We are indeed trying to find out the reason for this coincidence, although studies in that regard are still pretty illusive. Hence, we term it as coincidence to satisfy the momentary curiosity of ours.

Eeeeeeeeeeeeeeeeeeee

Doctor whomst'dlyaint

I get the reference. The OG rick and morty

@@nathanbrawley7256 yes that's the one

Nathan Brawley well the OG Rick and Morty was Back To The Future.

But do the stick figures miss you?

They might

is your aim getting better?

no don't

the sun iz a deadly lazer

@@areg7182 U FRICKING MISSPELLED A 2 LETTER WORD!!!111!!

@@Ratmania7777chill it's a meme

*noooooo*

I find it interesting too. I'd love to use it against creationists.

@@pranavarvind4281 I use it against atheists

Nestrislia Crystal how does the Anthropic Principle go against atheists? If anything, it totally removes the necessity for a god to exist for us to exist, and then we can apply Occam’s Razor, meaning that it’s more probable that the universe just came out of nothing than an arbitrary god coming out of nothing and then creating the universe.

no

Good point

no, not a good point, that's not how it works, the people who measured it obviously know what they're doing, they don't draw lines on a sheet of paper and measure them with a ruler

Fuck me now

Wouldnt space expand to the point of 5 hydrogen atoms per m3 and then stop expanding? meaning its at equilibrium like nearly everything that doesnt get energy added to it constantly. (at 5 hydrogen per m3 the shrinking and expanding is equal)

But centimetres are a pretty arbitrary unit. Measure it in inches cubed or metres cubed and the number is no longer 5.

@@jeffvader811 you're thinking of the spiral. If you just count along(1, 1, 2, 3, 5...) Then this is true.

wow very super

@@dabest8147 I think the original comment I replied to was deleted. For context it went something along the lines of "there are 5 atoms of hydrogen per cm^3 in space" and they tried to correlate that with the Fibonacci sequence :)

nuke4sen yes

It's deeper than that. We are a thought.

nuke4sen could we, yes, but there is no reason to assume that we are

Anticonny It does matter i think.. i'd like to know

We cannot be in a simulation, because that doesn't explain consciousness. Consciousness is no 'illusion' of a physical reality... Perhaps astonishingly - because we all simply assume it's real - there is no objective scientific evidence for a physical reality. Physical reality is an illusion of consciousness. www.scottowen.org/topic/luciddream

o O 0 maybe

What if we are a simulation inside of a simulation which is in part a simulation inside of our simulation?

o O 0 it's more likely than not

Kado: The Right Answer is one hell of an anime about this topic.

o O 0 We can't know if we live in the "real" reality or not and we'll never be able to tell what the "real" Reality truly is. It could all be a simulation inside a simulation inside a.... and so on.

This Science is amazing! Tell me again how sheep's bladders may be employed to prevent earthquakes.

I'm a fungi.

Wait a minute… **Jeopardy theme plays** What?

exactly,

en.wikipedia.org/wiki/Baryon_asymmetry#Regions_of_the_universe_where_antimatter_dominates en.wikipedia.org/wiki/Annihilation Jokes aside about being a random Joe, it is indeed very unlikely as we probably should have already detected such disturbances. Take in account that curvature of space does not make two particles uncollidable, otherwise it would be a very radical property of space that remains undiscovered and would require a theory compatible with current knowledge, plus any missing positive evidence for whatever such theory predicts. Furthermore, you should already know that in it's verbatim sense, "undetectable" is a concept science is not anyhow interested, if that's what you meant.

Me too. Doesn’t mean we couldn’t have brought up something new to a real table of study!

So would there be an undetectable anti matter mirror universe? I kinda like that idea. Seems legit.

AndyPiedram123 nope the shape of the universe should have no effect on life as far as I know

but every coincidence is highly unlikely, so to add on to you, i believe there is many universes with every possible combination of everything and we happened to live in this one

The inflationary theory allows for a region of flatness the size, or bigger than the observable universe and still be extremely curved as we zoom out into the whole size, wish according to eternal inflation might be 10^(10^30) times larger than the observable universe.

How would the curvature of space time be effected by an infinite universe?

In other words, the anthropic principle + many worlds interpretation. My hypothesis is that the net energy in the universe is zero. We started with nothing, but nothingness can split into positive and negative energy (like quantum foam). No matter how much you split zero into positive and negative matter/energy, we still get a flat universe. We would just be occupying the portions of space in which positive matter just happened to never cancel out with the negative. Antimatter could easily be repelled by gravity, dispersing into deep space.

hahahah that's funny, someone else said I have a pancake butt so I made an entire video dedicated to them. I'm starting to wonder if mine really is flat though.

Benjamin Weissman DAMN SHOTS FIRED.

lol Benjamin, I was hoping you'd say that your original comment wasn't actually directed at me...butt knowing that you spent your time to watch one of my videos just to see what my backside looks like has given me a good chuckle.

Jackal Unleashed you said butt lol

all light bends towards you girlll you the spotlight ;)

Raj Srikar Technically it would be, but it’s not.

Flat in 4d sense is different than in 3d sense :)

here comes the villain of everything

3D

Underrated

ImagineBaggins That's a good question; first, where do those shapes come from? A: the Cosmological Principle, AKA FLRW metric. We already know there are 3 possible topologies for 3D slices of ST, which we input in the FLRW solution via a parameter k=0,+1,-1 for each; feeding this metric into the Einstein eqs wields the Friedman eqs, which, by a lil trickery, allow you to compute k (topology) from the (observed) energy density! But, remember that the CP imposes _tremendous_ constraints on the 3D slices - assuming that such a change of spatial topology occurs, even in the ''''preferred '''' cosmic frame, probably is beyond the FLRW sol., i.e., it's counter to observation Refer to others if u like ;)

It comes from the first law of thermodynamics. Such a thought experiment is irrelevant because energy cannot increase or decrease in a closed system, such as our universe.

This is true _locally_ ; what about _globally_ ? Is energy globally conserved in GR, _always_ ?

Our universe is a closed system, therefore energy is conserved. Even as it expands, the mass-energy which appears in the form of a smaller mass defect is perfectly cancelled out by the increase in negative gravitational potential energy as a result.

Also, I think underscores have to have spaces around them to work as an italicising tool.