Why the Universe is Flat I The Great Courses

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The Earth may not be flat, but the universe is-and that's because it possesses zero net total energy. If it had positive or negative energy, the universe could be saddle-shaped or even spherical. In our case, the universe can be made from nothing. Get ready to get your zen on; philosophy just met astrophysics.
Presented by Neil deGrasse Tyson
Learn more about astrophysics at www.TheGreatCoursesPlus.com
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#ShapeoftheUniverse #Astrophysics #NeildeGrasseTyson

[@HamidMN]

"Try that at home" Usually in every video they say "don't try this at home". You are a very dangerous man Neil :P

[@crisrobles3425]

Okane xD

[@IKnowYouDidnt]

Well, I took his advice. I just tried it... Wound up blinding myself in one eye... Now, I gotta sue someone... Neil will be hearing from my attorney, because it was his stupid advice... I'm not qualified to shine a light on the wall... WHAT WAS HE THINKING?

[@MichaelMolash]

We do have a badass here.

[@jilliansmith7123]

Riot: what kind of flashlight did you use? Poor baby! Hope you win your lawsuit. 8^O

[@moses777exodus]

The concept of "Nothing" represented by the number "0" (zero) did not exist in the beginning. The number "0" (zero) is a relatively recent human innovation in mathematics. But, there has always been "1" (one). The fact that one (1) exists and can generate the position/concept of "nothing" (0) shows that there first exists one (1). Thus, nothing (0) does not truly exist alone: One (1) must first exist that can generate the position/concept of nothing (0). Mathematically, Absolute nothing "could be" expressed as 0 to the power of 0, which can equal 1. "Nothing" IS "Something"; because, it comes from "Something". Moreover, since Nothing (perceived) is not Nothing (actual), then it is possible for Something to come from Nothing (actual). Because, Something (1) is inherently pre-existing within Nothing (actual), hence, 0 to the power of 0 can equal 1. Simply put, Something (1) exists before Nothing (0) can exist.

[@Roabie]

Amazingly educational as always... Thanks a lot Neil De Grasse Tyson

[@LucidDreamer54321]

It depends on how you define “universe”. If you include available space rather than just the location of material substances, then the universe is not flat. Instead, it is extremely large (possibly infinitely large) in every direction. The Cambridge English Dictionary dictionary defines space as “everything that exists, especially all physical matter, including all the stars, planets, galaxies, etc”. However, the Collins English Dictionary defines universe as “the whole of space and all the stars, planets, and other forms of matter and energy in it”. Notice that the second definitions includes all of space.

[@matthewa441]

Thanks Dr Tyson. While I still don't get it, I'm getting closer thanks to you and your love of this stuff

[@stuartstuart321]

Yes makes no sense at all

[@SkY_LeVeLx]

﴿ يَوْمَ نَطْوِي السَّمَاءَ كَطَيِّ السِّجِلِّ لِلْكُتُبِ ۚ كَمَا بَدَأْنَا أَوَّلَ خَلْقٍ نُّعِيدُهُ ۚ وَعْدًا عَلَيْنَا ۚ إِنَّا كُنَّا فَاعِلِينَ﴾ [ الأنبياء: 104]

[@bernicejenkins1515]

You are in a cult.

[@philipmorise7970]

Neil's videos always motivate me to want to study the humanities and the social sciences.Maybe its just me!

[@PRINCE-fj6iu]

😂😂

[@casaliemerson6576]

The episode is from the new version featuring astrophysicist Neil Degrasse Tyson. In one episode he cites a book that has a title like "the flat world" to explain how the characters' lack of sensory references didn't "perceive" the third dimension. This is the book I'm looking to read.

[@willd2156]

4:28 whipped with physics rap 🔥

[@user-em6oj4tq9c]

Hey there this year is 2022, Message to coming generations, no matter what happens in future, be kind to other people other creatures, choose your leaders wisely, enjoy your life because it's short, do whatever you like but don't hurt any person. I'm writing this message in my 20s will update every year.

[@neildodd1319]

Well its been a year!

[@ivanrankovic72]

I finally understood what flat means. Cleaver explanation.

[@IusedtohaveausernameIliked]

I don't understand what a big knife has to do with it.

[@davemart]

When you say zero energy is that basically referring to Total mechanical energy (Ep +K). What about the mass ? i.e E=mc^2? Is this being accounted for?

[@crawfordsmith3700]

I have sometimes watched this guy's presentations since around 1997. I still cannot understand what he says.

[@ourlegacy6092]

Because he said almost fake info

[@SkY_LeVeLx]

Great Channel. Care about our universe.👌🍫☕😃

[@mreza913]

I understood what he said for sure and I need one genius to help me what is the answer of 6-1=?

[@MN-pu6qx]

A very interesting topic explained well for the layperson - I think... (26.6.21)

[@antoniomontana6589]

What if the real shape of the universe does not apply in any way or form to our 3D perspective of it. Therefore we will never know or comprehend the actual shape of it because its just mathematically/physically and visually impossible. Kind of like a 1D being wondering what the shape of its 2D world is, and the 2D being wondering what the shape of its 3D world is, us wondering what the shape of our 4D simulated universe is, and so an infinite number of Dimensions asking themselves the same question for eternity. The fact that we're barely in the 3rd level of ever wonderness, makes me feel somewhat insignificant.

[@karmasutra4774]

Do you think we keep moving along the dimensions and evolve that way like souls leveling up? So many theories out there

[@doganhalli2690]

I've been wondering about the shape of the universe for years. I was so curious that I even did the thought experiment Einstein described. Of course nothing happened. I finally saw it in my dream. I share this information in the hope that it will be useful so that it does not die with me. The universe stands on the pointed end of the cone without touching anything, as if two cones coincide diametrically. The outer surface is almost pearly white. Beneath it is a floor of the same color that does not touch the universe. From the angle I am looking at, a golden yellow object emerges from the left side of that floor and passes over the universe without touching it by drawing an arc. There is a light there. The outside of the universe and that ground are illuminated by that light. Its color is close to the crimson that occurs at dawn after the sun goes down. #physics #universe #shapeoftheuniverse #paralleluniverse

[@alanroberts7916]

Its MACDONALDS !!! !!!

[@jedgould5531]

I watch a lot of these videos, and I nearly understood what net energy of a large object is.#tenforce yes, and it doesn't help when Neil speaks haltingly about a flat universe, nor how flat, nor how it's unusual.. Does this mean the Hubble's first target, Andromeda, was lucky?

[@casaliemerson6576]

ALGUEM LEMBRA O NOME DO AUTOR E TITULO DO LIVRO CITADO EM OUTRO VIDEO (UNIVERSO - DISCOVERY OU HISTORY) COMO EXEMPLO DO POR QUE TEMOS DIFICULDADE EM ACEITAR-PERCEBER OUTRA DIMENÇÃO QUE NÃO AS 3? O LIVRO É ANTIGO E DESCREVE A PERSPECTIVA DE UM MUNDO DE DUAS DIMENÇÕES ( THE ...FLATTENED.... ).

[@danhryniszak6612]

I can see with telescopes that the majority of Stars in Galaxies tend to form in a flat plane, I cautiously assume this is because of Gravity acting on the Stars and the center of each Galaxy. I can also see at night with my unaided eyes that the Stars in our Milky-way Galaxy also tend to exist in an appropriate 2 Dimensional Plane. And I also cautiously believe this is caused by of Gravity between the Stars and the Center of our Galaxy. However, Galaxies can be seen in any direction from the the Earth or orbiting Satelite Telescopes. I have never seen any photos showing that the Galaxies are tending to act on each other and concentrating into a 2D plane. If this was occurring, it would mean that the Forces of Attraction between Galaxies would be great enough to first pull them selves into a 2 D Plane and from there, great enough force to pull themselves back into a point or Singularity. Once back in a point singularity, repeat the Big Bang. If as I have been told, that Galaxies are moving away from each other, then why would the form a 2 D Plane?

[@jacobpettit9157]

That still leaves the question what created nothing. How could nothing exist if nothing created it.

[@hulkhogan4203]

but what happens if you go up

[@russhughes2170]

I have question i genuinly dont know the answer to plank is the smallest length right and you cant get any smaller but what happens in the space between plank when space is curved like say a black hole really any massive body would work for this question is the plank itself stretched or are new plank length created? If new plank length are created in space instead of stretching them is it possible the exponential expansion of space in all directions could be caused by the creation of more space around a gravity well in other words is it possible the same force that is pulling everything together is also causing the expansion of space by creating space between the plank

[@russhughes2170]

I belive it would also explain why we cant really see its effect at solar system scale but at a galactic or intergalactic scale since all matter would be creating space it would slowly push out but with most bodies being trapped by gravity you you wouldnt notice it unless your frame of reference was far enough away that the force of space expanding from the mass your on would over power gravity

[@russhughes2170]

Not a scientist or anything i had this idea and couldnt find anything about it was just curious if the thought intrests you guys enough to think about it

[@SkY_LeVeLx]

سورة : الأنبياء - Al-Anbiyā’ - الجزء : ( 17 ) - الصفحة: ( 331 ) And (remember) the Day when We shall roll up the heavens like a scroll rolled up for books, as We began the first creation, We shall repeat it, (it is) a promise binding upon Us. Truly, We shall do it.

[@IusedtohaveausernameIliked]

That was a nice discussion but I still don't know what "flat" means in this context.

[@kenikos744]

So just how do you take nothing and turn it into something? I think his definition of "nothing" must be different than mine.

[@woodedape]

So is the universe square or oblong?

[@path7000]

Flat means equal, balanced, same, equilibrium, net zero, uniform, etc

[@rictheanonymouser873]

what if the universe started as a bubble but then popped and is now spreading outwards(expanding) into a flat plane of, like a water balloon splashing on the floor. and we are so infinitely tiny compared to the size of the original bubble we cant even perceive it. only theorize.

[@rogerdiogo6893]

I thought those times were behind us, flat earth, flat galaxies, flat universes, I guess I was wrong...😂😂😂

[@benmaghsoodi2067]

Much to my surprise, there is an astonishingly large number of physicists and cosmologists on KZbin.

[@NikolasJo]

Good

[@SampleroftheMultiverse]

And inane people on TV

[@Rolandclarke1964]

Where else can they pontificate? 😉

[@ajv336]

Just not in the comment section...

[@tenforce]

What i dont like about all the explanations about this topic is that they don't tell that the universe is not "flat" in a sense of a 2D plane. Because i think many people that are not so familiar with the topic might get into the misconception that the scientist are talking about an actual 2D flat surface, and are confused!

[@craigdaubbeats-rapinstrume9185]

@@PlzPr3sspl4y Me to. I've been trying to figure this one out for awhile. Like I get there are other ways to use the world flat, but in the infographics they use flat surfaces. It's like they're intentionally trying to confuse us.

[@nnn-ej3zm]

@@craigdaubbeats-rapinstrume9185 Same! And one more thing i don't understand is dark energy and dark matter to me from this point of view it seems like they decided that there must be dark energy and dark matter because without it Einsteins theory makes no sense. Like what if he was wrong. Not to mention that Einsteins theory is a way to explain Newton's gravity..what if he was wrong.

[@alanroberts7916]

@@nnn-ej3zm "what if einstein and or newton were wrong?". If it's ever proven that anything in science is wrong it will be changed. That's why it's science. And not forever fixed like religion.

[@antoniomontana6589]

@@nnn-ej3zm they don't know any better than two long dead scientists who were limited by the technology of their time, yet still made world changing scientific discoveries. If not for Einstein we'd still be in the analog era. If not for Newton, we'd probably still use horses for transport. Although today's horses would likely be powered by Tesla batteries.

[@redacted7104]

Can you please provide some resources to visualize the universe? I tend to get so confused about the 2D visualization of the flat hyperspace.

[@TheBaldingPied]

Just imagine in a few decades "Look at how far science has come. Just a few decades ago we thought that the universe was flat"

[@Keys879]

I was just going to say that. To be honest, I am of course no renounced physicist, I personally feel as though the universe is not Flat. That just doesn't make sense. Maybe it adds up to some ideas we currently support, but just as the Earth beneath us appears to be flat on average, it is truly spherical. Just gigantic. The same I think can be said for the Universe. It appears flat because we are so small and the physics of time and space fool us. I believe it could be toroidal.

[@Ghostowl657]

The analogy is backwards though. Local measurements of space-time show curvature, but universal averages are extremely flat.

[@medhatfaris5808]

The Great Me-sama lol

[@philipchristiansen1495]

You are correct in saying we can only see a small portion of the universe, however when we say the universe is flat, we're talking about the geometry of the observable universe, since well, that's all we can talk about. The distribution of heat in the CMB do strongly suggest we're in a flat universe.

[@TheBaldingPied]

tbh, I was less making a comment about the validity of the flat universe thing and more making a reference to the flat earth theory. But discussion is discussion. Discuss away.

[@Skythedragon]

Something had to be flat...

[@danilomarvel5657]

flat earthers are loving this

[@harrislam]

well no one can deny the earth being flat now that the entire goddamn universe is flat huh

[@Eric-lx8hp]

Goes around comes around

[@bananian]

I'm starting the Flat Space Society.

[@jilliansmith7123]

Yeah, but a hockey puck isn't "flat," it's flattened on two sides, but you point out it still has height...so it's NOT flat. Mathematically, flat would have only two dimensions--wouldn't it? Width and breadth? I get putting a Mentos into a hockey puck, but I'm not sure why you don't just put it in your mouth or its original container...

[@nando1881]

Ok.... now I`m gonna have fun with my flashlight :P

[@OgierSchelvis]

That's what she said, though.

[@chasptrs.4922]

I am going to have fun with the wall; bang my flashlight against it and create parabola flashlight sound waves, might come in handy some day.

[@MultiCrazytalk]

nando1881 i'm going to have fun with my fleshlight

[@ericz8086]

spoderman comstock hahahahahaha

[@bitchass1004]

fleshlight*

[@MarkGutknecht]

With all these great Astrophysics and powerful minds that populate the KZbin comment sections, Neil deGrasse Tyson and his peers should take a break!

[@Elohiym72]

Mark G lol, my man

[@noahway13]

Funny, but if you think about it, this type video attracts a certain IQ of people. Not like this is a monster truck video.

[@seamus9305]

Neil's a great teacher. I've listened to long excitations of what "nothing" is and what it is not and the idea that the universe came from nothing is nothing like the definition of "nothing" as we know it.

[@7Earthsky]

It's a joy listening to this man.

[@EmeraldView]

I like how Neil makes things understandable.

[@EmeraldView]

I fell asleep in the first 5 minutes.

[@EmeraldView]

Enter the Braggn' , Touche'

[@alanroberts7916]

I may have to watch this five times but it's worth it to fully understand the points that he makes.

[@t-72k16]

it's crazy, we are always focused on our lives, our short/long term goals, our day to day routine. when we take a step back and zoom out a bit, your mind is blown at how big the picture really is.

[@thomasscoot904]

What a smart man.. he makes listening to his intepetaion of how things go on in the Universe fun to pick up on

[@Dannys99887]

Is there any way to get scientists like Tyson to quit using the word "flat" in a context which confuses the global geometry of the universe with dimensionality? The correct word is "Euclidean," and it refers to the curvature and topology of the THREE DIMENSIONAL universe. In a Euclidean universe, parallel light beams remain parallel across the universe, and the included angles of a cosmic-sized triangle of light beams total 180 degrees. In the context of the FLRW metric and the standard model of cosmology, a “flat” universe, in the absence of Dark Energy, expands forever at a decreasing rate, has zero net total energy, and is without boundaries. It's effectively infinite in its THREE spatial dimensions.

[@pingpong2456]

I AGREE, JUST SAY ITS NOT BIG BREASTED

[@7Earthsky]

I think i agree with this...Though maybe it's just even better still to just say infinite instead of spherical or saddle shaped.

[@sycodeathman]

Dannys99887 This explanation is meant to be aimed at people who don't necessarily know much about space-time :P Of course they're going to dumb it down a little, because the main point of this is not to teach people the absolute hard science explanation, but to inspire curiosity so they can start to build up their knowledge base on their own.

[@realityversusfiction9960]

Reference KZbin video Why the Universe is Flat the Great Courses. I am utterly sick of the outrageous claims and lies promoted by these self-professed Euclidean flatlander based academic dunces, who are so fundamentally dumb, they cannot even work out the correct length of a simple circle. Using a 120-centimetre length diameter line 1. Multiply the 120-centimetres line by 3 2. The Circles length is 360-centimetres 3. Every Circle has 360-degrees The Circles length is 360-centimeters, 1 degree is 1-centimetre long 4. Multiply the 120 centimetres line by 4, the length of the circles square is 480-centimeters The Circles length is three-quarters the length of the circles square. As such, it is an unequivocal fact that all of their equations that have involved the use of pi (As per Einstein's) in relation to any form of differential calculation are no more than approximations, that possess no greater mathematical value than that of a near guess. So it follows that they are not worth the paper that they have been written upon. And given that as the ancient Greeks awareness of the nature of the Earth and the Cosmos was limited to an apparently flat visual perspective and a far horizon, they might be forgiven for believing the Earth was flat. The same cannot be said for modern day academics, who given and despite all of the modern day knowledge available in relation to biological structures, atomic structures, particle physics and astrophysics etc, come to the even more childish and ludicrous conclusion that the entire Cosmos is flat. www.fromthecircletothesphere.net

[@MrPatrickHenryCheryl]

The easy thought-experiment way is to draw parallel lines along a surface. If you try it on a ball they'll get closer, if you draw it on a saddle shape they get farther from each other. It's only on a flat sheet they remain parallel. Beams of light work a similar way. Remaining parallel (instead of coming closer to or farther from each other with distance) tells us they're moving through flat space.

[@kapilbsingh]

love the way Mr. Tyson explains it

[@theemissary1313]

Thank you for explaining the curvature thing about the universe with the orbit of a planet there, it's something that has always confused me about cosmology.

[@ZFlyingVLover]

the net energy in the Universe is 0 and not positive or negative so the net energy is FLAT. The universe isn't physically flat just the net energy graph

[@brianpatterson8407]

i agree...net energy.. if all matter is energy then all of universe has energy.

[@RedTriangle53]

Einstein's theory of general relativity disagrees. It claims that the curvature of space-time is something like a physical geometric figure that extends into 4 spacial dimensions where the final dimension is related strongly to time. Energy distribution is the cause of the universe curving into this dimension, and thus if the energy distribution is net 0, the physical curvature of the universe is net 0. This is also the reason why dark energy has to exist. If net energy is 0 there has to be outwards curvature equal to the amount of inwards curvature, which means some sort of repelling force. The geometric nature of the theory doesn't necessarily mean that the mechanics are caused by geometry as we know it, but to claim that the net energy is 0 is equally valid to claiming the universe is physically overall flat.

[@planet2k168]

"zero energy" means zero kinetic/potential energy. matter in universe having energy E=mc2 is not accounted in "zero energy of universe". energy contained in matter is missed. Am i correct. anybody plz

[@sauldula]

You can have negative potential energy.

[@bright3335]

dar'man beskar Ordo what are you smoking the first law of thermodynamics is conservation of energy

[@fistpunder]

I am still trying to figure out how something that has 3 dimensions or axes up, down, left, right, front and back, like the space we live in, is flat? What do you mean it is flat? Only two dimensions? How can I understand this better?

[@aspie96]

One dimension is removed in the images. The sphere would be an hypersphere.

[@jefdamen2977]

It's not flat, he represents gravity as flat. Check 0:37 But gravity doesn't work like that in reality, they should have drawn a lot of gravity planes, one for each 0.001 degree or better.

[@chagew8966]

James Demos universe has 2 dimensions: space and time

[@noahtheevil6949]

I was thinking about that too. Even if only gravity is flat, that means that countries aligned to Guatemala have gravity = 1 and the countries aligned to Canada or Argentina have gravity = 0 I didn't even get the flashlight analogies.

[@sleepy314]

James Demos not the number of dimensions. We have 4 dimensions ... 3 space like dimensions and one time like dimension. But if you construct a triangle in any orientation the angles will sum to 180. This is just an ad. Google for more info on what curved space time means.

[@dyinteriors]

This supports the conclusions of Krauss and Hawking. It also implies that their is no need for a deity in the traditional sense of the word for a " creation" brilliant little talk. Thank You Neil!

[@bannistg]

Excellent!!!!!!!!! Well done!

[@kainotomoc]

"You can create the entire universe out of nothing". You still need energy to sustain the structure of it at the smallest detail and in a balance.

[@bazookabankai5186]

The key words that i noticed is " you can create "

[@bazookabankai5186]

Of course i believe the the creator created the universe from nothing

[@alanroberts7916]

@@bazookabankai5186 of course I ask who created the creator. It takes intelligence to create a god. Right? Because the god people will say it took an intelligent designer to make the universe.

[@bazookabankai5186]

@@alanroberts7916 if you ask who created the creator and then who created THAT creator we will have infinite regress and we will never be created or even existed or talk about right now, we must have the first cause ie uncause cause

[@alanroberts7916]

@@bazookabankai5186 who says??? Are you afraid the god idea falls apart if you even just ask these questions? Why would simply having an open mind to ask these questions stop the univerese(s) from functioning. The bible says god(s) in the first commandment so maybe a different god for each level of universe.

[@cillyhoney1892]

Okay, sooooo I'm stupid and didn't really understand this explanation. My intuition tells me the universe is an expanding sphere because that's the shape of an explosions and the universe is the result of an explosion, in fact it's still exploding. So how is it flat? Who ever heard of a flat explosion? and for something that's flat it sure is thick in all directions, you know, like a sphere. If the universe is flat which way is up?

[@cillyhoney1892]

People like Kandi Klover is why we still need feminism.

[@ericz8086]

***** fuck you kandi

[@CADF-bz2si]

Cilly Honey That's what I was wondering as well.

[@kakuzu12345]

Cilly Honey Space-Time as the fourth dimension, bends like a flat two-dimensional plane. Space itself is expanding, like a balloon being filled with air.

[@rationalplus3181]

Cilly Honey One of the difficult things about science is that sometimes scientists use old words in new ways. When Neil talks about the universe being "flat", he doesn't actually mean it's flat like a pancake. He's using a special definition of the word "flat", which only applies in this one context. (He really should have explained this better in the video). Think of a beam of light, traveling through empty space. It should go in a straight line, right? Well, it turns out that sometimes a light beam will curve off to one side, even though it's not touching anything. It turns out that the reason this happens is that space *itself* has a weird quality that makes things curve. We describe that quality by saying "space is curved". So the 3D shape of that space is still, ya know, space. But stuff traveling through it will drift to one side, because space has a weird quality that makes that happen. The most obvious example for this is gravity. We usually think of gravity as something that "pulls" us, just like a big magnet pulling a piece of metal. But actually, it turns out that what gravity *really* does is it "curves" the space around matter. (The closer you get to the matter, the bigger the curve). So if you've got a big chunk of matter, like the earth, and if something travels nearby, like a meteor, then the meteor will drift towards the earth, because space is "curved" in that direction. This is one reason scientists think of gravity as the most mysterious force. It's not a simple "pull" action like magnetism; it actually messes with space itself. Anyway, when Neil wonders "Is the universe flat?", he's not actually asking if it's flat like a pancake. What he's saying is: If you shot some beams of light from here to the edge of the universe, and if those beams of light didn't touch anything along the way, what path would they take?" If the universe is "flat", it means that all the curves cancel each other out over super-long distances. So like, as it travels from here to the edge of the (observable) universe, the light beam will curve one way and then another way, but what's the overall effect? Do the curves all add up in one particular direction? Or does it perfectly cancel out, so in the end the light beam reaches its destination as if it had been traveling in a straight line the whole time? Turns out it's the latter. All the curves cancel out, and the universe is "flat". How did they figure this out? They got telescopes to look at light beams that were created at the edge of the universe. Then they did some fancy math and realized that everything was traveling in straight lines. Basically. I'm *sure* I'm not explaining this quite right. For one thing, Neil talks about "positive" and "negative" energy cancelling each other out. As I understand it, gravity can only be one of those two things, and I don't know what the other thing is. (Dark energy, maybe?) But whatever. The point is: He's using a nonstandard definition of the word "flat". (And if you ever hear someone claim that the universe is actually a "flat hologram", that guy is using yet *another* definition of the word "flat". Science is weird.)

[@Nimbus3690]

Such a great video

[@neobourgeoischristum5540]

it all nets out to zero, which is intuitive, he explains it well.

[@Keinlicht]

This is such a weird way to say that the 3-dimensional universe is a closed system with net gravitational distortion of zero. It's not literally a euclidean plane.

[@danielroberts6208]

That is not what he said. Yes, there is no net distortion. I didn't hear him say anything about it being a closed system. If dark energy is real, we can't be in a closed system. The dark energy needs to come from somewhere.

[@ComradeDragon1957]

+Daniel Robert There was an article that said they may of disproven Dark Energy because they found that the universe(maybe maybe not) isnt accelerating. Theres an article somewhere on the webs about that.

[@danielroberts6208]

I expect it will change a least a few times before anyone figures out how it really works. I personally don't even believe that the speed of light is a constant.

[@shirleyblair9811]

I could see the idea of even the Speed of Light 'accelerating' and constantly going even faster.

[@No-oneInParticular]

Daniel Roberts speed of light changes all the time. The only reason it doesn't change now is because it's literally been defined into fact so that it will never change. Same with gravity sadly. Different measurements all over the glove regularly but they don't bother with the changes because it gives funny answers to math questions. Physicists prefer perfect complete equations that look hard to solve but are in fact an exercise in futility and are more or less just a very long high school algebra problem where the result is pre-determined

[@JusAnotherUTuber]

I like turtles

[@1984potionlover]

Turtles are good, especially when they go all the way down ;)

[@jilliansmith7123]

Nancy Cousintine: turtles,, those shelled preverts, always go all the way down.

[@nirmalpadwal2055]

I didn't knew u have a youtube account as well!! anyways, i am subscribing...

[@ghostlack]

nice explanation!

[@giovannilacala8003]

Neil is actually jumping to conclusions, because we haven't directly observed the entirety of the universe, only the observable part. It's like saying the earth is flat, because from our frame of reference the curvature is so small we can't see it. So yes, it's possible the universe is flat, but it can also just as easily be curved. Look up Pbs space-time on KZbin, and their latest video.

[@giovannilacala8003]

+TheMathias95 I realize this, but we yet have the technology to make a triangle large enough to cover the entire universe.

[@dependent-wafer-177]

+TheMathias95 Dude, I drew a triangle and I still can't measure the angle of the earth. Should I draw the triangle on a piece of paper, cos I drew it on my ipad, I hope I don't have to draw it on paper cos those things are hard to find these days. I've searched for papers on the app store even the play store still can't find em. Please tell me, I really want to measure the angle of the earth, it's so easy to just draw a triangle and get it, I'll finally do something sciencey and show off to my friends.

[@dependent-wafer-177]

TheMathias95 Looks like my act of being a dumbfuck didn't work. You said drawing a triangle will allow you to measure the angle of the earth. I was trying to point out that saying that is like saying drawing a literal triangle. You can't measure the angle of the earth by just drawing a triangle, you know like taking a piece of paper and literally just drawing a triangle like the way kids do at school.

[@MJHdesproj]

+Giovanni Lacala Dude - you're completely right - also the conclusion that the universe is flat had NOTHING to do with measuring curvatures in spacetime but rather the drawing in degrees based upon distance from the Cosmic Background Radiation... What he's saying is flat out wrong

[@MJHdesproj]

+Giovanni Lacala By the way - you don't need to draw a triangle over the entire universe - that's crazy, you only need 0.5 degrees of inclusion at reasonable distance to accurately determine general shape (mean and principal curvatures) but are not accurate enough to determine exact curvature in the case of curved objects - there is bias in the curvature estimates since cylindrical and spherical patches cannot be represented exactly by a quadric

[@dwk204]

Guys... he means "3-D flat" not the 2-d flat you guys are familiar with...

[@mapu1]

With 2d diagram. Real good job illustrating what he says. He is literally showing us a square, and going cube is flat, just like this, but he is skipping the words cube and square.

[@davidsirmons]

Dae Won Kim but it's not flat 3 dimensionally, there is full dimensionality on all three axes. Space is 3d.

[@MegaMercernary]

davidsirmons If you were in 4 dimensions of space, you’d see a large flat universe of 3 spatial dimensions. Just as if you visited a 2 dimensional universe.. You may stumble upon a 2D person, uttering that same thing you said.

[@pardhasaradhireddycherukul1595]

there is no 3D or 2D he is talking about net energy and law of conservation.According to string theory whole universe is come from no where, its vibrating in different frequencies, posses different physical chemical properties.

[@rickjag4928]

@@MegaMercernary How do YOU know?

[@omarrobau8007]

You know what happened the last time we thought the world was flat.

[@Woraug]

Omar Robau Yes. At the time we used the evidence we had and came to the conclusion that it was indeed flat. When we discovered evidence that suggested otherwise, it was tested, proven, and accepted as fact. If there comes a time when we discover evidence that suggests contrary to what was stated in the video, we'll test it, prove it, and it will become accepted as fact. That's how science works.

[@rustyrusky]

Woraug No, science is not about "predicting" the shape of an object. For the purposes of science an object is pointed to or postulated in the phase we call the hypothesis. In science ALL our terms are rigorously and unambiguously defined so that everyone who learns about the theory, can, with his own mind, understand and criticize it. This eliminates all concepts, that is, relations between objects, from scientific discussions. The terms "force", "field" and "energy" are not scientific, they belong to religion just like "god" and "spirit". A concept cannot act upon an object (i.e. "the electric field accelerated an atom"), this is an irrational explanation. You cannot "give an object some energy" as Neil puts it here just as you cannot give someone a slice of love or justice. "Energy" is defined as "the ability to do work" yet they treat it like an object. Energy is regularly transferred, converted and they say you cannot "create or destroy" it. These are clearly qualities of a object (wikipedia states that energy itself is a property of an object). However, pressed for an answer every "scientist" will say it's a mathematical concept. "Space time" must be one of the most enigmatic words in physics. Is it a concept or is it an object? Neil clearly refers to the latter since he's talking about its shape. Yet I've yet to see an illustration of space time. These people like their words to have different meaning depending on what they want to tell you. They say the photon starts as an object, travels as a concept and arrives as an object. "Virtual particles" must be the height of this nonsense, a contradiction in terms.

[@-_Nuke_-]

Omar Robau hahahah +1 that's EPIC!

[@khxml]

That was beautiful!

[@612Tiberius]

This concept is what confounds creationists - the whole "something from nothing"/Big Bang/quantum fluctuation phenomenon they deliberately misinterpret as a misnomer because they can't (or "won't") conceptualize a universe (and ultimately sentient human life) coming about through entirely natural means. They claim to "understand" Einstein's E=mc2 matter-energy equivalence formula; but refuse to intellectually see it through to its logical conclusion; of the universe both coming from, and eventually going back to "nothing", while still maintaining this zero-sum equivalency the whole time.

[@chagew8966]

612Tiberius An equation in balance doesn't change it's contents on its own. If there was nothing, there was no reason for something.

[@612Tiberius]

chagew8966 What Cosmologists call "quantum fluctuations" (the temporary change in the amount of energy in a point in space, as explained in Werner Heisenberg's uncertainty principle) still happen all the time throughout the universe, and are part of what is studied at the Large Hadron Collider (LHC) at CERN and other particle colliders around the world; in which elemental particles spontaneously emerge from the vacuum of space, exist fleetingly briefly, then just as quickly recollapse back in on themselves, leaving the vacuum as if they were never there at all - during which the total amount of energy present remains the same. This is on the exceedingly small scale, but the same phenomenon has the potential to also exist and happen at all scales up to and including universal. Thus, the universe in which we presently exist can, and according to the leading experts in the field of cosmology and astrophysics based on decades long and continuing study, very likely did emerge from a large-scale and sustained quantum fluctuation in the pre-universe void (The Big Bang event) the result of which we are still in the midst of (present time-space), and which, according to one theory will at some time unfathomably far in the future recollapse back in on itself leaving only the same void (now the post-universe void) from whence it emerged - with the total amount of all energy throughout the entirety of the whole eons upon eons long process remaining the same (the whole "matter and energy are not lost or gained, only changed from one form to another" concept). I hope all that explains the issue a little better.

[@robinsuj]

IF the universe is flat,then it will never go back to nothing, that only happens in a closed (or positively curved) universe. I write IF, because the margin of error in the measurement of te curvature of the universe is about 5%.

[@612Tiberius]

pabloeli29 Exactly; there are still competing theories, more refinement of measurements left to be made, and still unanswered questions regarding dark matter, dark energy, gravitons, etc.

[@chagew8966]

612Tiberius I find that really cool. Nevertheless, we observed these particles coming in and out because of what we did. There was a reason. Someone did something. Someone made a choice. There are no natural laws that construct a choice. Yet these choices effect the natural world. I believe that this line of thinking would lead to a realization of the spirit, leading to even more questions. I don't pose it as the answer though, just food for thought.

[@poppyorangeflower]

Wow. I did not connect to anything the guy said in this video. :(

[@skebess]

That's because you're blonde.

[@adflicto1]

sKebess lol man

[@taitywaity1836]

2:48 Tyson's description of a parabola and a hyperbola is swapped according to the proceeding diagram, which I think is correct.

[@mayaforpeaceful]

*universe* dark matter : source of 85% of gravity in universe dark energy: giving universe an acceleration. wow….

[@Opethfullcovers]

If the universe is flat, so is the earth. The end.

[@davidbrainerd1520]

amen

[@rikard1414]

Hahaha you are flat :D

[@marioluigi6407]

What the hell that's totally not the point xD

[@1nonlyrawbert]

that's like saying if the earth is flat then everything on earth is flat

[@Opethfullcovers]

Robert Esquivel Don't be an idiot.

[@jtarrats100]

Love Listening Niel speek about Astro c cosmology.

[@livingstonest]

Wow. Never saw it that way before.

[@dougzembiec9995]

God does exist, his name. Is Neil de Grasse Tyson

[@dougzembiec9995]

Maxx Kroes Morgan Freeman was playing Neil de Grasse......

[@anyoneofus9948]

I want to find a little person, put them him in a dog costume with a butt flap and give him a collar that says PLANET and LET him crap on his lawn so when he comes out all angry the little person kicks him in the shin. Then I will explain a better way to categorize the planets while the little person wipes his butt on his shoe

[@RandomRads]

Doug Zembiec hahaha....I was about to say this n then read urs. Never mind

[@ComradeDragon1957]

Nah,Neil de Grasse Tyson is just one smart cookie compared to us.

[@adrianmejia2732]

ArtisanTony Nice sentence there, smart guy Lol!

[@michaelg1915]

I don't understand how 111 people can give this a thumbs down but OK... Pretty good video Neil! Thanks for all you do to keep us informed!

[@steveg1185]

I don't know about the rest of you, but I gotta go to work now!

[@Jejeco]

Hmmm.. I've never look at the big bang like that. It makes me thing of another definition for the word "nothing". But it's indeed very fascinating. Thanks for the chat mate! have a very nice weekend.

[@rbrb5686]

love this guy

[@ahpacific]

I like Neil but as a Physics graduate student I'm forced to acknowledge that not all practicing physicists are great at pure unstructured reasoning. Even if the universe does have zero net energy, in no way does that imply "we can make the universe out of 'nothing'". There is such a huge gap in logic to go from that premise to that conclusion. Simply consider, that the separation of that "zero net" into constituent positive & negative requires "something".

[@lithium23]

on a podcast neil explained the shape of the universe to be an octagonal shape with each side having a 3d square going into it and out of it.

[@ja1111112]

Do you can recommend any different sources about this topic? I don;t understand this (being honest) and I want to understand

[@Curious112233]

Since the expansion of the universe is believed to be accelerating, that can be likened to adding energy to the planet so that it flies out of orbit. Neil said that was a positive energy situation, so how can he claim there is zero net energy?

[@libalchris]

I think part of the problem is that we're both talking about different things. I'm talking about what the total energy of the universe is (what we measure it to be) while you're talking about how everything we observe can come from nothing. I mentioned earlier an unsolved problem in cosmology known as baryonic asymmetry. It's definitely something needing to be solved, but ultimately, from what I understand, has little to do with the total energy we observe today.

[@parkjihoon394]

i went to try this at home and i have a flashlight but i dont have a wall, what do i do?

[@loupax]

So, the universe could be an ever expanding disk, resting on four elephants which stand on a turtle, the Great A'Tuin?

[@djNemo72]

Way to put words in his mouth. Scientists don't say the universe is a disk, he doesn't say that. Theres a difference between an euclidean sphere and a flat sphere. The word disk is not mentioned. When you look up in the sky you see stars, not besides you in a disk shape. It's all about: does light take a direct or curved path in this sphere.

[@alcubierrevj]

Please reupload in HD.

[@SampleroftheMultiverse]

Tilting the plane thru the inverse square field. Always thought it model something more. The equal and opposite image looks more like object hitting each other not flying away.

[@miltondelacuesta8304]

I actuallt support the idea of a spherical universe. To me，it could explain how wormholes are supposed to take from one place in space to another. Also as our perception of earth is flat，we may percieve the universe in the same way，only localy flat.

[@rkpetry]

Sailors floating on the sea have paid little attention to the depths until something bumps... [01:39] That is not a celestial mechanical elliptical orbit: your primary focus is misplaced...

[@robharwood3538]

Would be nice for this to be uploaded with better video quality (>360p).

[@xchazz86]

Another interesting fact, consciuosness also have zero net energy. The entire universe may just be a figment of somethings or someones imagination.

[@asyncasync]

no

[@Imsorrythatimanidiot]

Toyo Masauce You're scaring people 😂

[@Ed-sg4iy]

+Toyo Masauce, false. The part of the brain responsible for consciousness most definitely has energy (at least mine does; don't know about yours)

[@nickdehart5702]

All I could think of while watching this is Maynard James Keenan and all of the thoughts in his head. 🎸

[@jadigg5]

So what would be different about our universe if it had net positive or net negative energy? How would it affect earth and how we live

[@vanscoyoc]

I got it finally. Great video. When he say the universe he is including time with space into the flatness. I was thinking it was just space wise flat. This isn't something you can just visualize by going out and looking at the sky. The universe isn't flat in just 3D space. That's obvious.

[@EatanAirport]

I researched what you're saying and the the wmap does indeed point to a zero-point energy universe however zero-point energy can not be used as a cosmological constant. A positive value is calculated when this is tried.

[@MrMZaccone]

As an example, we learn in school that the sum of the interior angles of any triangle always add up to 180 degrees. The minute we step out of Euclidean (planar) geometry however, this ceases to be a truism. We would never know this however without measuring triangles over large distances on a globe or sphere. The math is our model. The observations are reality. If they match ... now you got something spectacular!

[@brianparsons1439]

Sharing.

[@nick13113]

When we discuss electromagnetism, relating to the charge on an object, a neutral object is defined as something that has equal an equal number of positive and negative charges. In terms of physics, it has "no charge". that's how physics is, it's not the obvious, it's an approach that makes sense of experiments and calculations, not what is intuitive.

[@EatanAirport]

Look up "Cosmological Constant" (Wikipedia is the best). It identifies the problem that zero-point energy should be a cosmological constant, however instead of the equation calculating zero, it adds up to -1.

[@zajec11]

Creationism gets ridiculed yet once again

[@meatrace]

As it should be.

[@CyberiusT]

He didn't say a word about creationism - you did. Now, if you felt that creationism was made to look completely stupid... Well, that would be something else.

[@trexgravyM91]

Something from nothing sounds like creationism. Or its the same if not similar. How can you conceive one and not the other? Why aren't people able to understand an idea without judgment?

[@libalchris]

This doesn't have to do with the total energy of the universe, but the value of the cosmological constant (which does contribute to the total energy I might add). Physics predicts a very large value, while we observe a value very close to zero. I'm fairly familiar with this area of cosmology, and I don't see where you're getting "instead of the equation calculating zero, it adds up to -1"

[@Shane8]

So your argument is: "My car was designed, therefore the entire universe was designed." Bravo. That is the most impenetrable display of logic I have ever seen.

[@cristianfcao]

Flat in this case means euclidean, which means that if, for instance, you draw a triangle in the universe (using galaxies, say) and add all the the angles you've measured, they'd add up to 180 degrees. If you do the same on Earth you'd think it's flat at first, but if you use very long distances (a triangle uniting Mexico, Saudi Arabia and the North Pole, say) you'll get an angle higher than 180°, which is what happens on a positively curved space (sphere). On a saddle you'd get less than 180°.

[@PeterDB90]

Does that mean that the entire universe can be reduced to nothing? If you forced all of the sums of the universe to converge and cancel each other out, we would end up with nothing. That does make me wonder whether there's a catalyst that "encouraged" this "nothing" to become the universe.

[@mattman20132]

so when something is bending spacetime in one direction, does that mean somewhere else in the universe, it is compensating for that by bending the opposite direction?