So what are the most popular theories that may suggest what is beyond the edge of the universe?

no kurde rzeczywiscie

>Once you understand this, project this thought experiment into the 3rd dimension.
Does that mean our universe is awesome? Because that is so awesome.

So if humans went to a sufficiently distant galaxy and wanted to get home, it would actually take less time to just keep going in the same direction?

>A Balloon is used for this representation because it can be "blown up" to demonstrate expansion.
>ONLY the surface of the Balloon exists.
Wouldn't it just be easier to say that expansion occurs as a relation between bodies and not some absolute property, i.e. all bodies are just getting further away from each other at an increasing rate? That way you don't have to imagine something that doesn't make sense.

If you project that exactly - It's obvious - if you had some hypothetical ship that traveled faster than light and you would go in a straight line relative to your start - you would end up where you started if you moved faster than the expansion as well.

No because space expansion is faster than light can travel - hence than ships can travel.

If quantum theory is right - the space will rip eventually, if it's bullshit - space will go on expanding forever.

So no matter how far you got - you'll eternally be closer to where you started, with every passing moment in time even MOOOORE closer.

The balloon example is good for demonstrating expansion of a 2D universe. Just as this pic is a good example of how gravity works in a 2D universe. The impression in the fabric is imperceivable to those existing within the 2D place of the fabric, but it's still there and still has and effect on them. Same way the volume in a balloon is imperceivable to those in a 2D universe. Now to be able to visualize how the expansion of space and gravity works in 3D you need to be able to visualize 4 dimensions.

>Does that mean our universe is awesome? Because that is so awesome.
Yes

>it would actually take less time to just keep going in the same direction?
Sure. But why wouldn't you have gone the short way in the first place?
>inb4 Thought experiment. Unlikely to happen given a whole bunch of limitations.

>That way you don't have to imagine something that doesn't make sense.
Why doesn't it make sense?

Assuming a homogeneous (no special places) isotropic (no special directions) universe, that's one possibility for the shape of the universe, the [math]\Omega > 1[/math] case. To the best we can measure it, [math]\Omega = 1[/math], but it may be slightly higher or lower. An [math]\Omega[/math] close to 1 means the round trip around the universe would be very long, though.

Inflation (the idea that the early universe underwent very fast expansion) predicts that the universe should look homogeneous and isotropic with [math]\Omega[/math] very close to 1, even if it didn't start out that way, because the enormous expansion makes it that way. It's very possible that homogeneity and isotropy don't even hold for the universe as a whole, just the part we're in that inflation acted on.

>this pic is a good example of how gravity works in a 2D universe
Not at all. That pic only shows the curvature of space, which doesn't contribute to gravity on nonmoving objects. It's a contribution to the deflection of light passing near the sun, and the reason the result is twice what you'd get from a naive application of the equivalence principle, but it's not at all a demonstration of how the gravity in our everyday lives works. For that you need spacetime curvature.

An analogy for the space-time part of gravity is two longitude lines on a globe, where north is analogous to the future. Starting at the equator, the lines are parallel to each other, which in the analogy corresponds to not moving relative to each other. As you go north (wait), the curvature of the globe makes the two longitude lines bend toward each other (the objects start moving toward each other).

There are also non homogeneous theories out there

arxiv.org/pdf/1512.07364.pdf

>Why doesn't it make sense?
I can't imagine a "balloon" that is only surface and has nothing inside or outside of it

>I can't imagine a "balloon" that is only surface and has nothing inside or outside of it
Okay
Cool
Have a blessed day

youtube.com/watch?v=ajbN3dlDfzE Starting at 1:16

No. You could never get "around", no matter how long you keep going

Just imagine a regular balloon, but only consider its surface as the universe.

Would you please provide me with something that backs up your claim that the universe has no edge? As the adage goes, what can be asserted without evidence can be dismissed without evidence.

I also think this thread is a bit brash when it comes to asserting that because a thought experiment works well for explaining a phenomenon (blowing air into a balloon representing the metric expansion of space), the thought experiment must be true, i.e. that we must live on a 3D (4D with time included) membrane of sorts. In general this is a laughable notion (not that we live on a 4D membrane but what I said earlier), so I'm assuming there's more to this that isn't talked about for some reason?

If you feel like replying to me, please specify whether you are talking about the universe or the observable universe.

Do you honestly think the idea of spacetime folding into itself comes from the balloon analogy? It is just an oversimplification to explain expansion

The best I can do is give you a FAQ sheet Harvard that will disagree with most of this. That doesn't change what I believe.

cfa.harvard.edu/seuforum/faq.htm#top

My point was that most people that ostensibly know what they're talking about claim that our universe is an n-dimensional surface with no edges, and that traveling through the universe is the same as traveling across an n-dimensional surface. I want to know where this idea comes from.

The rest of my post was a caveat that just because A and B share a property or are subject to the same phenomenon, making the argument that A = B is specious.

We have measured the curvature, and thus the geometry, of space. It's flat to a very very small degree, so the chances that the universe in infinite are extremely high.

More of the same, but you can only see a radius of 45 billion light years

The total size of the universe is 10^1200 times bigger than the observable universe

They are describing a closed universe. They are wrong.

Experimentation actually points out to the universe being flat.

Allow me to go balls-to-the-wall retarded for a minute: But user, if you can move in 3 directions in space, how can it be flat?

Flat in 3D doesn't mean flat in 2D

But those are just analogies, because it is pretty hard to imagine it with more dimensions.

There are only 3 possibilities

The universe is flat, the universe is closed or the universe is open.

Each one excludes the other and cover all the possibilities.

Experimentation points out to it being flat.

In this particular cosmological context, "flat" refers to the curvature of spacetime. It doesnt mean the universe is flat as in 2-dimensional

So it's just bad pop-sci then? Most of the time it's stated as fact without any mention of it being any form of analogy or simplification.

I assume flat entails infinite in all directions, closed entails traveling in one direction eventually makes you end up in the same position, and open entails what exactly?

Do you have any "real-life" examples of objects that are flat, closed and open?

a plane is flat
a sphere is closed
a contorted plane is open

I can visualize a plane (2D object) and a sphere (3D object), but I can't visualize a contorted plane, as by my logic contorting it would no longer make it a plane; would you mind elaborating on what exactly a contorted plane is?

a plane is a 3d object

...

Oh, you mean an airplane?

...

>without any mention of it being any form of analogy or simplification
I never heard someone using this analogy without it being obvious or without using qualifiers that clearly indicate an oversimplification

nobody knows the shape of the universe yet

.

the universe is BIG

a nano bot cannot survive going through a black hole, however.
Anything that comes near a black hole goes through a process called (not kidding, it's the actual name given by NASA..) spaghettification.
Litterary means that the object is cruhed into a 100'th milimeter thick, and pulled out kilometers long.
Happens with everything. Space dust, comets, stars, fucking everything that goes near them.
There's NO way to go through them, at all.

The only way I see that you perhaps COULD go through a black hole is to somhow neutralize the gravity force from the hole, but that would most likely have to be done to the hole itself and not the spacecraft.. And if you neutralize it's magnetic force, I suppose it will just..collapse and fall appart?

Mhm..
Well. I suppose we have a way of deleting black holes then, if we ever test it out and its sucessful.

Also, bonus info.
You can orbit black holes, most of them have the same gravity force as stars with the mass of R1, meaning you can orbit them just like you can orbit a star.

*THE MORE YOU KNOW*

Also, second bonus info.
Speakin of orbiting stars...
Magnetars... That's something you DONT want to orbit around. They litterary consume suns to grow more powerful if they are too close..
Which often is the case, actually as most stars are in multi-star solar systems.

So, I'm not well versed in physics, but the universe being flat fits well with the findings that the universe is a projection (ie. that the 3rd dimension is projected), right?

Actually, edit..
If you neutralize the magnetic force of a black hole, it wouldnt collapse and fall apart.. it would most likely explode, seing it as there's no force that keep that gigantic mass so tightly together anymore..
Kind of like a spring.. if there's a force, it keeps pushed together, remove the force and it will expand quickly...

Sooo.. neutralizing the magnetic force of a black hole would most likely cause a super nova like expolsion, seing it as most black holes has the same mass as stars..

Shiet. yeah. never mind.. really bad idea to neutralize their magnetic force.

no, it just means on the large scale the universe is flat--i.e., there's not an intrinsic curvature to our universe. Everything we're seeing, gravitationally, then it due to local (big stretch of this word) perturbations in the form of matter clumps. Unless you're getting close to incredibly strong gravitational fields (i.e. black hole merger), then essentially it means you can work with a flat background spacetime and just do general relativity as a first/second/etc. order correction.

Interesting. So is this flat as in a flat 2d plan in 3 dimensions scaled to our 3d universe in a 4 dimenional (?) view? I thought the universe being curved explained how we are able to see further than 13 billion light years (despite that the universe is only 3 billion years old).

I thought black holes were held together by the gravitational force of a shitload of space shit at the center.

>Travel in any given direction along the surface of the balloon for a distance of 2 * pi * r. You'll be back where you started.

The fuck are you saying dumbass. Space expands faster than light. Yes, there are no edges, but the universe isn't similar to a sphere either. Just because it's infinite in every direction, doesn't mean it acts like the surface of a balloon. The Universe doesn't act like the surface of a balloon, as which you have described it to do. The idea that the Universe acts spherically has been nearly discredited with the advancements made toward accurately mapping the CMB.

These topological models are very speculative and people need to realize that something can't be infinite and have a shape.

youtu.be/ZMgrAnX3ViE?t=30m30s

"Space" isn't real. There are rules defining how objects behave and there is a component which lets us define an area around the objects. Space is the imaginary area around the object.

Any part of the outer universe moving in any direction away "creates" more space. The universe can not be technically infinite and have an entropy lifespan though.

And no, this has nothing to do with GR or SR

Yeah?
All that space dust, remains of comets and what not is compressed into a super dense blob.
All things in the universe have a magnetic force, even you have a magnetic force.
So imagen if you take a fuckton of things, and press it into a super small space so it becomes extreamly dense, that magnetic force will become massive.
So, if you somehow could neutralize the magnetic force that keeps it together, it would act like a spring, shooting all the atoms it holds everywhere.
Pretty much like how a star goes through a super nova.

It would just, explode.

Theory goes that we live in a multiverse, in which literally everything that could ever happen, does happen, all the time.

We do not know of the size of the universe yet, but till now, we have always found bigger systems, structures we wouldn't have found possible before, as well as incredibly smaller structures.
I conclude from this that there have to be bigger systems still, adding up to the one point where you can only call this massive thing you have just summarized "existence".

Also, the problem lies with the definition of "the universe", because if it indeed is all of time and space and thus which is contained in it, do you then conclude there have to be other "times" and "spaces" which are seperated from our system ?

Space can be infinite on a certain plane though.
One could assume that matter as well as time and space are infinite, but an other higher unit of measurement yet to be found is finite.

What's the actual evidence supporting this? I'm not saying it's so, I'm just saying it sounds a bit too convenient and simple.

I mean I get the distinction between this being a thought experiment, and then trying to apply it into practice. But even then, the idea of "magically" teleporting to the other end of the universe seems unlikely given that the dimensions required for that are simply concepts we've come up in mathematics and dubious frameworks like string theory. Even with the idea that there is simply "nothing" beyond space, which means there's no getting there because it doesn't exist, which means we're stuck inside this virtual "bubble" that is our universe, which basically means that the universe is everywhere and there can be no edge to it, as it would have to expand infinitely to every direction.... even then.

It would seem far more fair to me, to say that we simply don't know. And that from a practical perspective, it can't happen anyway. Because the expansion of space would exceed the speed limit of any object trying to get there anyway.

I've yet to hear, or understand a good, well-founded theory of what would likely be out there. A trampoline works as an example for GR and the curvature of spacetime, because we can observe it, and have a shit ton of evidence of it. But this? Not so much.

>In this particular cosmological context, "flat" refers to the curvature of spacetime.
Just space actually. It's the curvature of a 3-dimensional slice of spacetime taken at a given time after the Big Bang. Both the intrinsic curvature of the spacetime due to gravitation and the extrinsic curvature of the slice in spacetime due to Hubble expansion contribute to the curvature of the slice. A flat universe is the case where they cancel out due to the density of the universe being just the right amount (the critical density).

The usual picture given for the open case is a saddle shape, but that doesn't really capture it fully. The striking feature of the open case is that you have an exponentially growing amount of stuff nearby.

Concretely;
closed -> circumference of a circle is [math]2 \pi a \sin(r/a)[/math]; it goes to zero when the radius is halfway around the universe
flat -> circumference of a circle is [math]2 \pi r[/math]
open -> circumference of a circle is [math]2 \pi a \sinh(r/a) = \pi a (e^{r/a} - e^{-r/a})[/math]; it grows exponentially

Build a shape with two regular hexagons and a regular pentagon at each vertex, and you get the classic soccer ball shape approximating a closed sphere.

Build a shape with three regular hexagons at each vertex, and you get a tiling of a flat Euclidean plane.

Build a shape with two regular hexagons and a regular heptagon at each vertex, and you approximate an open hyperbolic plane. Even if you just draw it on paper, you can quickly get a sense of how the thing blows up.

Pic is someone's project to crochet a piece of hyperbolic plane.

kys, avatar-fagging is against the rules, and i have reported you to the moderators.

You would need to be travelling faster than than yourself and the expansion of the universe combined

>universe is only 3 billion years old
Ummmmm??!!

>beginning with "so"
ghey millenifag detected

everything is wrong with this

it is. dont listen to popsci faggotboy

>what is an analogy
Autism is real

I bet her dick is super fem.

so like are you like my grandpa? like die already

That is very cool crochet

Sure, since space is an imaginary framework in which we house the observed rules of matter interaction it can be any size, shape, or not that you want.
People need to think of 'space' as an observation point and not anything special

Space has properties including geometrical curvature, electromagnetic fields, and other fields.

>space is an imaginary framework
No. not at all