Do we know which side of the edge of the universe is nearest to us?

Originally posted by Maslo
reply to post by ChaoticOrder

 

It very well may be curved and we just can't detect it, but if it isn't, then the theory that the Big Bang created space-time with it, is completely flawed.

Why, even an infinite universe can expand just as well as hyperspherical finite universe. Infinities come in different sizes. As an example, both integers and even numbers are infinite, but there is two times as much of integers than of even numbers. Just because we cannot imagine infinite expanding spacetime as simply as an expanding sphere does not mean that the idea is not mathematically consistent and valid.

If something is infinite it cannot expand. There is no 'beyond' infinity contrary to what Buzz Lightyear said.

the right side

reply to post by fiftyfifty


No... infinity can expand. However infinity has no shape, it's infinite. It cannot be a sphere or anything else. The idea of a sphere which can contain infinite space is indeed mathematically invalid. Infinite flat space is just that - infinite flat space.

Originally posted by ChaoticOrder
reply to post by fiftyfifty

 

No... infinity can expand. However infinity has no shape, it's infinite. It cannot be a sphere or anything else. The idea of a sphere which can contain infinite space is indeed mathematically invalid. Infinite flat space is just that - infinite flat space.

edit on 2/10/2012 by ChaoticOrder because: (no reason given)

I agree that a sphere cannot contain infinite space. But the statement that infinity can expand simply does not hold. If something is expanding, it must have an observable end or edge or a volume. I am claiming neither that space is a sphere nor that it is infinite. I also disagree in what you call 'flat space'. if space was flat then there would have to be a top and a bottom. If it is infinite, it is infinite in every dimension.

reply to post by fiftyfifty


Star

Infinite can not be flat

For it to be infinite it needs to have no boundary

For ever and ever

reply to post by fiftyfifty

But the statement that infinity can expand simply does not hold.

Of course it does. There are different sized infinities.

Originally posted by magma
reply to post by fiftyfifty

 

Star

Infinite can not be flat

For it to be infinite it needs to have no boundry

For ever and ever

"Flat" in cosmology means the spacetime is not curved, not that its two dimensional.

reply to post by fiftyfifty

But the statement that infinity can expand simply does not hold. If something is expanding, it must have an observable end or edge or a volume.

I thought the same thing when I first heard of the concept of expanding infinity. But it is actually a mathematically valid concept. CLPrime explained it to me a while ago:

Originally posted by CLPrime

Originally posted by ChaoticOrder
I would also like to know how the Universe can be expanding but also be infinite like they say.

Let's look at it this way...
Picture the series of Integers in the form of a line:

... -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 ...

...extending to infinity at either end.
As it stands, there is only a single space between each number. However, what happens if we add another space between each number? The distance between each number increases, but the infinite nature of the series stays the same.
This is the same as the expansion of the universe. Each of the universe's 3 spatial dimensions can be represented as an infinite series of numbers on, for example, a Cartesian grid. Each dimensional axis extends to infinity, but the distance between each point increases.
This is how universal expansion works, whether the universe is infinite or not.

I also disagree in what you call 'flat space'. if space was flat then there would have to be a top and a bottom.

Clearly you don't even know what 'flat space' means. Again, let me quote something from CLPrime:

Originally posted by CLPrime

Originally posted by ChaoticOrder
So it's like how large gravitational fields can bend space-time. You're saying that space-time is generally flat throughout the entire Universe unless disturbed by forces such as gravity? So would the spherical model perhaps represent some sort of Universe where space-time loops back around on it's self, or something like that?

Yep, all of those points are pretty spot on. The spherical universe is also the one where it's possible to see ourselves if we look out far enough... and, if we keep travelling in a "straight" line, we'll eventually come back to our starting point.
As Arbitrageur mentioned, it's still possible that the universe is curved like this. It just has to be such slight curvature that we can't detect it. That's why what scientists will usually say is that the universe is locally flat. The Earth is also locally flat to any given person standing on it.

reply to post by ChaoticOrder

This is the same as the expansion of the universe. Each of the universe's 3 spatial dimensions can be represented as an infinite series of numbers on, for example, a Cartesian grid. Each dimensional axis extends to infinity, but the distance between each point increases. This is how universal expansion works, whether the universe is infinite or not

I'm no mathemetician but I don't necessarily buy this. Space isn't a linear series of numbers so cannot be compared. In the number sequence, you are not increasing anything but adding more detail to what already exists. 1000 will still be 900 away from 100 (the distance). Anything which can be increased in size cannot be infinite as it would have to have a definite end point. If space is infinite then there is no end point to be moved further away. You can add fine detail to what's in the space but it won't change anything else.

reply to post by fiftyfifty


You are correct in a certain sense I understand what you are trying to say. One infinite space cannot be bigger than another infinite space. That much is true. On the first page Maslo made the following statement:

As an example, both integers and even numbers are infinite, but there is two times as much of integers than of even numbers.

However, that's not actually a very good way to put it. Clearly you don't have "two times as much", because both number sets are infinite, you could continue counting for ever with both sets. So you can not exactly say one has twice as many as the other.

But you can say one has a "denser number space"... now I don't even know if that's a valid phrase or term but it's simple enough to understand. In the integer set the "number space" is packed with more elements, compared to an equal amount of number space in the even number set.

Now when it comes to the expansion of space, you must remember it's not like things are moving further apart due to motion, it's actually because the space between the things in the Universe is expanding, "stretching out" if you will. And we know this, we've proven it with extensive observation.

So we know one thing for sure: we are always getting more and more space. Now lets say the Universe does have an infinite amount of space... if you add a bit more space does it become bigger? I'll leave you to ponder some thoughts... this is the mind-boggling nature of infinity.

reply to post by ChaoticOrder


Well surely this points towards the universe not being infinite. Although I have nothing to back up my theory, as I said earlier, I believe it is possible that our universe is expanding within an infinite space. Outside of our universe and other universes is 'space' but not like space in our universe. The space outside is truly void of everything. Therefore if there is nothingness it can't end because that would mean reaching a point where there was an absence of 'nothing' which of course is not possible. There is no such thing as absolute nothing however and the universes fill this void. Our universe is the measurable something within the emptiness of nothing.

(that above paragraph absolutely fried my brain so I hope it makes sense!)

reply to post by fiftyfifty

Well surely this points towards the universe not being infinite.

Not really. It's perfectly valid for space to be added to infinite space, the logic and math works fine. Which is what I was trying to explain in my last post.

But the rest of your post is not very legible... space is space and there is no other type of space. You can have empty space or space with energy in it, but that's it. Or you could possibly have a void, complete nothingness. And I don't know if a void is possible, but your logic about nothingness seems rather absurd to me.

What "hinduism" has to say about the universe:
Earth is merely but one amongst innumerable others that orbit in this universe, while this universe is among countless others that manifest from the immeasurable form of Maha-Vishnu, who is lying in the Karana Ocean. This Karana Ocean, which holds all of the material energies, is but like a cloud in a corner of the infinite spiritual sky, and this spiritual sky is filled with innumerable and gigantic spiritual planets where the true reality of life exists eternally without limitations.

i have a feeling that the Zenith direction is the closest 'edge' of the Universe


that is supposing that the material universe uses a Galaxy's profile as a model , an elongated disk, thinner at the edges & fat in the middle

the only confounding thing about that physical model is that the light shining into intergalactic space (or interuniverse space in the macro model) has been traveling at the speed of light outward for +14 billion years...
thus making the actual termination 'edge' very difficult to define

? is the 13-14 billion LY outreach of light past the last physical Star considered part of the universe... if that's the case there is no structured 'edge' to be found

I change my answer from left to up (I bet its a winner).
Its because of we probably living in a flat ribbon universe ?
For more serious discussion here is the Manyfold Universe.


Manyfold universe and whatever there is

Get your brain tired with these universes.links

Maybe we are in the upper right corner? ...but then again what shape are we assuming is the universe( if it has ends) ....... Square?oval?

Okay, I’ve read through and I’m understanding that I don’t understand: how would you describe flat space as opposed to curved space, got any links?

I'm probably very rusty but I’ll lay this out anyway...

If we leave the earth in a vehicle and we continue to travel in a straight line (we are eternal in this example) would we ever reach the end? I’d like some help with that quandary. You see, I don’t know, I’m definitely not a scientist of any kind, and I know the kind of conjecture a non-scientist can drive towards (like me, ya kno), but after reading and watching the docu’s I have, I reckon that if you were to travel in a straight line leaving from the earth, the curvature of the body that is the universe would put your ‘straight’ travel path off course, so to speak. I reckon you would continue traveling ‘around’ the universe until you came back to where you started. (If you could travel fast enough to outrun the apparent expansion of the universe, that is.)

So, I do think that, with some relativistic reasoning, we are at the ‘centre’, but then so is everything else.

I kinda want to be proved wrong here, ya know, if I could better my idea of how this works then I’ve at least made some progress in understanding.

...rip me a new one ATS

If the universe had a beginning and it is indeed expanding, then there mus t be a leading edge. The primordial photons or electrons created in the Big Bang or shortly after find themselves are rushing into the void of nothingness as .3 dimensional space continues to expand.

Amazing difficult to grasp what lies just beyond those primordial Photons or electrons.

Originally posted by blobby
has no one measured which side of the edge of the universe is nearest to us? as we cant be slap in the middle, so one side has to be nearer to us than any other side?


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edit on 2-10-2012 by Extralien because: (no reason given)

What edge, theres an edge? Where, have you seen it?
Whats behind it......

I think our only real evidence of an expanding universe is the Big Bang theory that ties in with how most objects appear to be moving away from us. It's a premature assumption that may very well turn out to be seasonal rather than expansive. Plus, we've only been observing space for a very short while.

I don't see an "edge" of the universe. I see our place in the observable universe as more like sitting on the tangent of a circle where every point that touches that circle feels like the middle, giving the impression that there is an edge to it, like viewing the horizon while sitting in a boat on the ocean.

"Expanding universe" may very well be our "flat earth."