What is the universe expanding into?

>>8752270

Could just be a hypersphere passing through a 3-d plane. In which case the hypersphere has a constant volume and the universe gives the illusion of increasing.

your mom

Perhaps it is expanding into ignorance?

>>8752270
>>8752275

This depends on the shape of the universe itself. Like this anon says, if the universe is a hypersphere the likely scenario is it's not exactly expanding, as a hypersphere is a closed geometric object and thus would not be infinite.

However, the most plausible scenario is that the universe itself is flat. We've measured the curvature of the universe and determined it... Doesn't actually exist. Of course with something as immeasurable as the universe, it's remarkably hard to be exact with anything - I believe the number is currently 0.4% there's a curve to our universe so faint it's undetectable to us right now.

What does this mean? A flat universe is not closed, so it extends infinitely. In this case it's not expanding either. What's actually happening is the negative space, the "empty" space between everything is increasing. While any information can travel at ax the speed of light, this empty space is by definition absolutely nothing, so is expanding much faster. To put simply, there is no center point that everything is getting father from. Rather, every point in the universe is a "center point" where everything else is moving away from faster than it is physically possible to move towards.

Alternatively, there is a chance the universe has negative curvature, but this would also form a non closed geometric object, resulting in an infinite universe that would expand in the same way as a flat universe.

>>8752270
The universe is expanding into time ?

>>8752833
If this were the case, wouldn't all atoms and elementary particles "accelerate" away from each other faster than the speed of light? Any life in such a scenario would be impossible.

The only viable explanation I can see is that somehow the gravitational force prevents this from happening, but this doesn't make a whole lot of sense either. Is the expansion of spacetime (which is what I am assuming you're saying is expanding) caused by a force, and if so, what is this force?

>>8752270
THE GREAT PROIMORDIAL DARKNESS
PRAAAAAAAISE KEK INVICTUUUUUS
REEEEEEEEEEEEEEEEEEEEEEE

>>8752277
>Perhaps it is expanding into ignorance?
I'm with this. Ignorance is the problem that's expanding in numbers.

>>8752833
>We've measured the curvature of the universe and determined it... Doesn't actually exist.
Unfortunately we have no clue how insignificant the observable universe is compared to the overall structure. It could be basically nothing, and the universe could have curvature too small to ever measure while stuck in the observable universe. It looks flat to us within the limits of our measurements, but we have no idea how close that is to being accurate enough.

After all, if I put my best bubble level on the ground, I can only conclude that the Earth is flat.

>>8753391
>>8752833
Lol you mentioned that, my bad. Skimmed too fast.

>>8752936
It's caused by dark energy. And the rate of pushing away is only a function of distance. Dark energy only pushes things away when they're really far apart, basically no gravity. Very far apart particles move away from each other faster than light.

>>8752270
The expansion of space is actually time "crystallizing" into space. Spacetime is constant, but the time interval is getting smaller and 3D space is expanding because of the conversion.

>>8752270
Another universe?

>>8752270
Un-iverse.

>>8753414
i thought light was the fastest thing

>>8753449
Moving THROUGH space is limited by c. Space itself expanding is not. Photons at the edge of the observable universe shot in our direction are moving away from us.

>>8753449
It is

>>8753414
I can't even begin to start picking apart which of these things is the most idiotic thing ever posted on a message board.

>>8753464
i hate when anons like you make useless posts like that

you likely dont know but want to feel superior

From the wiki article on dark energy:

>[...]Since it is quite rarefied — roughly 10−27 kg/m^3[...]

How the fuck do you measure energy in kg?

>>8753449
Space is not a thing. c is movement THROUGH space. The stretching of space itself is faster than c; this is why no light except that of our local group reaches Earth.

>>8752270
server rack

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598KB, 600x878px

>>8753414
When you get to the last part and its faster than light

>>8753505
Yeah man the universe b scary

What do people mean by the universe is flat? Do theyean if you zoomed out of the universe all of the galaxies will be aligned on a flat plane?

>>8753524
No. Flat in a higher spatial dimension.

>>8753527
How can a non-2d object be flat? Can you give an example of a flat 3d object?

>>8753491
>Kilogram per cubic metre is an SI derived unit of density, defined by mass in kilograms divided by volume in cubic metres.

Don't know what's the context but you've written a unit for density

>>8753491
If c=1 then the units of energy and mass are the same. This is just a convention.

>>8752854
reported

>>8753548
Yes, my post was badly written.

My question is, do they think that dark energy has mass, since they measure it as mass density? Why, then, call it energy in the first place? Is it just to prevent confusion with dark matter?

>>8753540
Does anybody have any examples of flat 3d objects? By this point it must be pretty obvious that I'm not a mathematician.

>>8753560
Ah, makes more sense now. I don't know the answer tho.

>>8752270
What if everywhere outside our "universe" is the real universe, and the "universe" we live in is the negative space?

>>8753540
I'm not the best at this, but in a flat 4d space, 3d (and lower) objects will seem normal. Kind of like at first glance, the Earth seems flat, but as you walk forward, you're moving on the surface of a big curved 3d object. So when you see a triangle on the ground, you will measure the angles as adding up to 180°. But in fact, the angles are slightly obtuse due to being on a curved surface.

Our 3d universe could similarly be the surface of a 4d hypersphere. Or some other 4d shape. As far as we can tell, there's is no higher dimensional curvature. We basically draw giant triangles in space and make sure the angles add up to 180. But there is a limit to our accuracy, and our observable universe could be laughably insignificant.

The question arises at all, because we see all objects expanding from each other with no point of origin. Space is some sort of complicated geometric object. Being flat in 4d typically means that 3d space (and matter) is infinite. A hypercube would mean space folds back on itself, creating an unbounded but finite space.

>>8753559
Don't be that guy...

>>8753540
>>8753563
In a flat 3D space, 2 parallel lines stay parallel, like the empty space we are used to. In curved 3d space they converge, like a black hole.

Gravity wells are a 4D curve though, where time is the most curved(or at least has most impact), most pop science don't mention that, but it is the most mind fuck part of Einsteins relativity.

>>8753637
That's Minkowski 4d spacetime, different than 4d euclidean geometry.

>>8753642
I know its not euclidean, I never said it was neither. Spacetime is a curved though, which is hard to get your head around.

>>8753652
>Spacetime is a curved though,
In a gravity well, i mean.
Before some autist corrects me.

>>8753660
I take it you made this correction because the universe is most likely flat?

On that note, why is it assumed that because spacetime is flat (just accept this axiom), it cannot be closed? Couldn't the universe e.g. be a 4d equivalent of a 3d cuboid? If we were living inside (or on the surface of) a cuboid, everything would appear flat until we reached the edge, at which we'd switch directions by 90 degrees.

>>8753709
I don't really know the geometry to answer that. But I don't think anyone really make any assumptions on space outside the observable universe. All we know is that the observable universe is seemingly flat, and that its not closed in on a scale where you can see the effects of it looking from one side to the other.

it's not, it's contracting due to dark expansion

>>8753709
It's totally possible. We could be the flat surface on a 4d tetrahedron or something too. It could be 100% flat locally, yet bend after a certain distance that we will never be able to see.

>>8753868
What would it even look like to be on a planet right at the corner, one step away from it

>>8753896
If you were to walk through a corridor that twisted in through the 4th dimensjon, you wouldn't be able to see any thing strange locally even though you are the one rotating, but you would see the rest of the world warping and twisting around you as you're walking forward. It would look the same way a dome shaped mirror looks when you pass through its focal point. Going from normal, to inverted. Only its the whole world around you.

>>8752833
Could you enlighten a brainlet like me about how we could detect differences in 4 dimensional shapes in a 3 dimensional universe? What would be the implications of a hypersphere vs a "flat" 3d space? I understand that these are primarily mathematical, but I'm not afraid of math
>t. enginurd

>>8753921
I'm guessing you couldn't see through the entrance to the corridor? Or it would be a warped version of the other side?

>>8753930
The more warped you are, the more warped the rest of the korridor would look, so inside it, looking out, things seem warped.
Looking through it from one side to the other (Depending on how it was twisting) all you would see would be a helix twist in the corridor and a mirrored world on the other side. You wouldn't be able to see the 4th dimensional twist, as light will just be traveling through it from one side to the other, in a seemingly straight line.

>>8753493
How do you stretch something that isn't a thing?

>>8754255
Sorry to hear that. But I'm sure you have a great personality.

we have this thread every day

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>What is the universe expanding into?

Why are people so sure they understand that optical effect? If you say the optics are well-understood then there is the implication that the universe is all fucked up.

However, you can also say, "I don't think the universe is all fucked up, I think there is something about this optical effect that I don't understand."

The latter is much more palatable to me but everyone goes with the former.

itself

>>8752833
>I believe the number is currently 0.4%

It's more like 0.0003% margin of error. We are very sure it's flat.

>>8752270
The concept of something going "into" something else is inherently spacial. Space is a property of the universe.

I'm not sure the question even makes sense.

The universe is getting older, when is the time expanding into?

>>8753414
You know, saying "dark energy" doesn't actually mean anything.
>>8753449
This doesn't have to do with speed, but space, the thing in which "speed" occurs, expanding.

>>8753496
This. It looks exponential but once the server rack runs out that's it. Most likely before that happens the simulation will be shut off. ;)