What Is Beyond The Observable Universe?

[awhalen]

universe is not flat it has three and some say it has four dimentions philosophically we can call it infinite. No one can measure its boundary if we say that the universe is finite its like counting sand in the shore ^_^ in the end even if the universe is finite or infinite we cannot measure its boundary ....

the universe is said to have four basic dimensions that make up our three dimensional space.
There are another seven that deal on a subatomic level.

This being said how can we philosophically call the universe infinite based on the information you provided?

 

[DaveC426913]

the universe is said to have four basic dimensions that make up our three dimensional space.
There are another seven that deal on a subatomic level.

This being said how can we philosophically call the universe infinite based on the information you provided?

I wouldn't spend too much time examining periot's argument. It's an 'argument by befuddlement'*, as in: after enough enough smoke and mirrors, one can simply finish with 'so no one can say otherwise'.

* © DaveC426913 20110412

 

[StateOfTheEqn]

I voted 'other' because the observable universe is just our past light-cone. Our past light-cone is like a slice of the onion and we make inferences about the entire onion from that one slice.

 

[SirFishSlayer]

Our guess the space and time in our universe is finite. However it is just hard to believe there was no time before the big bang and no content beyond our observable universe. It doesn't make sense how things can by finite. I mean what happened before the big bang and why are there boundaries at the ends of our universe?

By studying the universe and the physical world one can truly see things aren't orderly per se. They far beyond the realms of organized imagination and can only be understood with observation and empiricism. Limits on the universe would truly make things beyond confusing.

BTW, what do scientists think happened before the big bang. Since the universe is expanding according to most of the evidence today, the cyclical big crunch is unlikely. What do scientists think are the likely choices?

There is the "shell" of our universe which is our expansion into the emptyness of the "Greater Universe". Let's call that the "Greater Universe" the ExtraVerse. Within the ExtraVerse there may be other universes that are expanding into it...maybe even expanding towards ours.

If we talk about time as being the point of creation of our universe then we must also assume that it will end at the last light of the last star...or at maybe when the dust and black holes break down as they expand outwards into the ExtraVerse. But is that correct?

Should we think of time existing only as our universe expands into the ExtraVerse? That is silly. If we could some how transport ourselves outside of our universe (lets say 5 minutes in distance), and watch for it in that 5 minutes as it expands towards us...would we even see it coming towards us? Probably not since it is the very light and energy that is our known universe that makes up the edge of it. But getting back to us sitting there, waiting for it to come to us...if we transported ourselves with a watch, that watch would be ticking. So we wouldn't just come into existence as the edge of the universe passes us and we become a part of it again.

I like to think of time as something that existed forever before and will exist forever afterwards...our universe just exists in a minute portion of it.

 

[DaveC426913]

Should we think of time existing only as our universe expands into the ExtraVerse? That is silly. If we could some how transport ourselves outside of our universe (lets say 5 minutes in distance), and watch for it in that 5 minutes as it expands towards us...would we even see it coming towards us?

Funny thing about invoking magical abilities such as instant teleportation in thought experiments - they tend to run afoul of established inderstanding - such as SR.

I like to think of time as something that existed forever...

Ah but so did Newton. Einstein showed him up.

 

[SirFishSlayer]

Funny thing about invoking magical abilities such as instant teleportation in thought experiments - they tend to run afoul of established inderstanding - such as SR. QUOTE]

No "magical abilities"...just putting the variable out there.

Seems to be that our universe isn't creating more of itself as it expands. It is not creating anything, it is just expanding into a "space" that is void of anything until you put something in it.

So, what IF there is another universe whose edge was approaching ours? If they are living in their own universe's space and time and we are living in ours, then does the 2 space-times collide? What happens? Whose space-time would rule? Would they just merge if their universe's laws are the same as ours?

 

[Jake4]

you're making some large assumptions..

who's to say 'space' exists beyond our universe.

 

[SirFishSlayer]

Who is to say it doesn't.

Is there a truly empty place waiting for a universe to encroach upon it, or is the universe creating it as it goes along?

Again, what if there is the Multi-Verse thing happening and has been happening...Our universe in the grander scheme of the ExrtaVerse. Then there is something else out there and and so it is not empty. What do we call that "place" in between universes?

We would assume that it is truly empty...but we used to think that of deep space until we realized that there is stuff out there and our universe if filled with it, even if we can't see it.

BTW, love the discussion. Thanks guys.

 

[DaveC426913]

It is not creating anything, it is just expanding into a "space" that is void of anything until you put something in it.

No, that is not the current understanding. The universe is not expanding into any void.

 

[Jake4]

I love the discussion as well :)

I would say that it doesn't need to be one or the other.

The universe could be expanding, without creating and without there being a void in which it is expanding.

as Dave said above.. the current understanding doesn't claim the existence of a void. Truthfully I don't know how one would really describe this void anyways.

Outside of the universe, the void would have to be space-less, and time-less.

The issue with most of cosmology (at least in my limited experience) is that the real mathematical representations cannot be efficiently translated into simplified conceptualizations.

I feel like that's the issue with most physics these days, and with the increase in pop-sci books.. the truth is being twisted and contorted into a conceptual mold that it just can't fit in, which is the only con.

The pro, is that more everyday people are becoming interested in science. That is such an amazing thing... even if it's storybook science, the bottom line is everyday people are starting to be curious :) and I like that.

 

[DaveC426913]

The issue with most of cosmology (at least in my limited experience) is that the real mathematical representations cannot be efficiently translated into simplified conceptualizations.

I feel like that's the issue with most physics these days, and with the increase in pop-sci books.. the truth is being twisted and contorted into a conceptual mold that it just can't fit in, which is the only con.

Well said. Formulae can accurately describe structures that cannot be adequately represented by human-understandable analogies, which are, by-definition, faulty.

Most of us strive to understand the unknown by comparing to known concepts, and therein lies the flaw. There is no comparison for the universe.


That being said, it is all right to create analogies to help understand how a model works, but it's lossy process. You can't do the reverse; you can't use the analogy to extrapolate back to the model. (A massive object may form a gravity "funnel" - but we do not then go looking for a cosmic drain plug!)

 

[SirFishSlayer]

I agree with that...space-less and time-less. Both are associated with our universe...neither existing into what we are expanding into.

I think we should make the cosmologist translate the math into concepts. Tell them to just give us the Cliff's Notes version, in 150 words or less, each theory they used (or created) to come to their conclusion...otherwise the grant money goes away. I'd think it would be cool to see a head explode...or implode.

The thing that has always keeps itching me is: what if we are not alone. What if there are more universes out there expanding like ours is. What if that is the natural order of things. When our universe finally fizzles out, will there be just a bunch of black holes out there eating those smaller ones around them. Assuming that they will still be traveling. Maybe at some point, when they have consumed enough, they can start another universe. Or do they just fizzle out themselves through leakage? Then what?

 

[SirFishSlayer]

Well said. Formulae can accurately describe structures that cannot be adequately represented by human-understandable analogies, which are, by-definition, faulty.

Most of us strive to understand the unknown by comparing to known concepts, and therein lies the flaw. There is no comparison for the universe.

Agreed. We are just along for the ride.

My personal "Heaven" would be to have it all explained to me, after I was given the capacity to understand it, then let me watch the re-run...with the remote control with the buton to zoom in and out.

 

[Trenton]

I personally postulate that the observable universe is a very large black hole sitting in a universe that is infinite in extent and populated with all the objects we have in our universe as well as other ultra massive black holes.

This is not about Russian dolls or wormholes but it does fly in the face of more established notions such as that in which all time and space was crunched in a singularity that somehow exploded - the key implication being that there was no 'before' or 'outside'.

Ultimately, any theory rests on one or more points of faith. For example, that the fundamental constants and the laws of physics are the same everywhere and are invarient with time. We don't know if this is the case and we have very little in the way of proof but we would all think the burden of proof would rest with anyone who disputed it as we would all ask the question 'why would the laws of physics change?' - and not come up with any answers.

To me, a hardcore believer in the invarience of the phycial laws and constants, the idea of an 'act of creation' is totally abhorent. Indeed the big bang as a unique event directly contravenes the principle of the invarience of the phycial laws and constants.

For the moment forget general relativity and quantum mechanics and go back to what we were learning when still in dypers. 1 + 1 = 2 The question is this. Was there ever a 'when' or a 'where' in which 1 + 1 did not equal 2?

It would seem not. 1 + 1 = 2 is true regardless of wether or not there are any entities to add. It is completely independent of the existence of time and space, of matter and energy.

So are all the laws of math - and the laws of physics. It does not matter if there were no photons, the speed of light would still be c.

Extending the concept (the faith) further - to the laws of physics as they really are (rather than as we understand them), the existence of matter and light, space and time, must be a direct conseqence of the laws of physics. Therefore these entities must have always existed and extended to the complete (infinite) set of legal coordinates. Therefore there was a 'before' and an 'outside'

 

[Jake4]

I like to think of the possiblity of different mathematical operators.. other than our standard +,-,÷,* .. in other universes :)

 

[Trenton]

I like to think of the possiblity of different mathematical operators.. other than our standard +,-,÷,* .. in other universes :)

I wouldn't. It would contravene the principle of invariance of math and physical laws. Besides they are not other universes, meerly other multi-billion lightyear radius black holes. By definition [of the word], there can only be one universe.

There is in any case, no shortage of math operators as things stand. What there is a shortage of are decent accounts of the workings and implications of some of the more exotic ones (eg derivation of the equation for the Schwartzchild radius and its implications)

 

[Tanelorn]

What is beyond the observable universe? The unobservable universe.

What is the unobservable universe like? The unobservable universe is like the observable universe except that we cannot observe it because it is beyond the observable universe.


Am I missing something?

 

[SirFishSlayer]

What is beyond the observable universe? The unobservable universe.

What is the unobservable universe like? The unobservable universe is like the observable universe except that we cannot observe it because it is beyond the observable universe.


Am I missing something?

Stating it that way makes waaaay more sense. Now that you've explained the easy stuff, explain women to me...remember, under 150 words. Thanks mucho!

 

[Darken-Sol]

What is beyond the observable universe? The unobservable universe.

What is the unobservable universe like? The unobservable universe is like the observable universe except that we cannot observe it because it is beyond the observable universe.


Am I missing something?

prove it

 

[Trenton]

Women have a fundamentaly different neurology - and more eratic hormones. (10 words)

But what you are missing over and above what all men miss, is that you have forgotten to postulate what make the unobservable universe unobservable. In what sense is it beyond the observable? Is it too far away? behind event horizons?

I suspect that advances in telescopes will come to widen the observable, ultimately by orders of magnitude. After all I can remember being told that 'all the matter in the universe amounts to less than 1 percent of that needed to ultimately bring about a big crunch'

Today I note that there is an article on Wikipeadia stating the Schwartzchild radius of the (observable) universe is approx 10 billion lightyears. That shows we have counted up many times more matter than before - because we have better telescopes.

 

[Jake4]

Women have a fundamentaly different neurology - and more eratic hormones. (10 words)

But what you are missing over and above what all men miss, is that you have forgotten to postulate what make the unobservable universe unobservable. In what sense is it beyond the observable? Is it too far away? behind event horizons?

I suspect that advances in telescopes will come to widen the observable, ultimately by orders of magnitude. After all I can remember being told that 'all the matter in the universe amounts to less than 1 percent of that needed to ultimately bring about a big crunch'

Today I note that there is an article on Wikipeadia stating the Schwartzchild radius of the (observable) universe is approx 10 billion lightyears. That shows we have counted up many times more matter than before - because we have better telescopes.

Farther, yes, but more.. no...

the universe is expanding at speeds much higher than the speed of light, thus it is physically impossible for us to see any more of it.

That is what causes it to be 'unobservable'

And I'll state again, that I do like thinking of different operators :) Not in any serious way, but it's fun :P

 

[DaveC426913]

Women have a fundamentaly different neurology - and more eratic hormones. (10 words)

But what you are missing over and above what all men miss,

What?

 

[Chronos]

'Outside the universe' is logically inconsistent given the universe, by definition, includes all aspects of nature that have observable consequences - or in simpler terms, 'all that is possible to see'.

 

[ummm]

Okay! I read about the first three pages of this discussion and skipped ot the last page, having the last post on May18-11, 10:16. I guess classes are out for summer, but I noticed that the discussion seems to be repeating the SOS. Since I didn't read all of the pages I'll probably get flamed for not doing so if my questions have already been asked but here goes:

1) If, at the time of the big bang, the entire universe was in, say, maybe a little ball, maybe the size of a baseball, or golf ball, or smaller like a grape or my brain (okay nothing's that small), then what was outside that little ball? What did the parts or gas or whatever, that was in the little ball of universe, expand into? Whatever it expanded into, obviously had to be outside the little ball of universe.

2) Since I'm not a physics phD, I'm still laboring with the notion that nothing is faster than the speed of light. If that is true, how can the universe be expanding faster than that?

Thanks for any answers.

 

[DaveC426913]

1) If, at the time of the big bang, the entire universe was in, say, maybe a little ball, maybe the size of a baseball, or golf ball, or smaller like a grape or my brain (okay nothing's that small),

Much smaller than an atom.

then what was outside that little ball? What did the parts or gas or whatever, that was in the little ball of universe, expand into? Whatever it expanded into, obviously had to be outside the little ball of universe.

It did not expand into anything. The universe - everything - was simply very small. There was - and still is - no 'outside'.

2) Since I'm not a physics phD, I'm still laboring with the notion that nothing is faster than the speed of light. If that is true, how can the universe be expanding faster than that?

Space expanding is not a 'thing'. The expansion of space between things does not violate relativity.

 

[marcus]

...
2) Since I'm not a physics phD, I'm still laboring with the notion that nothing is faster than the speed of light. If that is true, how can the universe be expanding faster than that?

Thanks for any answers.

In usual motion, you get somewhere. In the uniform pattern of expanding distances nobody gets anywhere.

There isn't any destination that you are approaching (aside from some small local motions galaxies have in their surrounding space, which are much slower than light).

So expansion is not usual motion you ordinarily think of---the speed limit of special relativity does not apply to it.
================

relativity developed in two stages first special (1905) which gave us the speed limit for ordinary motion in our local surrounding space

and then general (1915) which allowed geometry to be dynamical and changing (especially over large time and distance scales, if less noticeably close by)

changing distances between stuff that is not, in an ordinary sense, moving is another name for spacetime curvature. (I didn't say space curvature. the curvature may not be purely spatial, it may only show up in spacetime) the approximately uniform pattern of expanding distances is just one type of spacetime curvature.

if you accept the 1915 general theory, then you have to allow for geometry to change dynamically----among other things this means distances can change at rates faster than c.
But those effects normally only show up at very large distances and long timescales.

Current expansion of distances is only 1/140 of one percent per million years. And only applies between objects not bound together by gravity or other forces. So widely separated galaxies. 1/140 of one percent change in a million years is tiny tiny tiny percentagewise.
but if the distance base is long enough it could amount to a rate faster than light.

 

[DevilsAvocado]

1) If, at the time of the big bang, the entire universe was in, say, maybe a little ball, maybe the size of a baseball, or golf ball, or smaller like a grape or my brain (okay nothing's that small), then what was outside that little ball? What did the parts or gas or whatever, that was in the little ball of universe, expand into? Whatever it expanded into, obviously had to be outside the little ball of universe.

THAT QUESTION IS VERBOTEN!

No no sorry, silly joke, of course you have the right to ask, and I actually 'struggled' with exactly the same question for years, and got several times the same 'reaction' as in my first sentence.

First hint you will find in Chronos comment, just before your post. That’s the short version.

The longer version is that we just don’t know... i.e. we don’t know if the universe is finite or infinite!

If the universe is infinite, your question becomes 'invalid', because it just goes on and on and on and on and… etc for all eternity. If you would like to make a 'picture'; imagine a computer that just adds a (random) number at the end of a (already) very large number:

382211534546249571707506749878740794978813573152867305453507764320658956233792005229311772993057049548155758228845860778017611126014402141...

There’s (AFAIK) no law stating that the computer ever will run out of a 'new' number to add.

If the universe is finite, the simple answer is related to Chronos comment, the universe we live in and do science and physics in – is all there is to 'investigate'. I.e. our mathematics describes the natural laws inside our universe, and does not say anything about what’s 'outside'. Furthermore, science is about making testable predictions, which can be verified or refuted by physical experiments (you never get a Nobel without experiments, ask Stephen Hawking). It’s tuff to go 'outside the universe' to make any experiment... If you wish to penetrate the 'outside business', you end up with 'supernatural things'. This is not what physics and cosmology is about.

However, to complicate this just a little bit – this last claim of mine is not entirely true...

There are very bright scientists, like Max Tegmark, who indeed speculate about multiverse, i.e. a lot of parallel universes (that are separated). Don’t ask me how Tegmark could ever verify this experimentally. Also in String theory there are 'mathematical investigations' dealing with the possibilities of "Branes" and larger extra dimensions. We are however forever "locked in" in our 3D world, our "Brane".

(Hope I didn’t make things worse... )

2) Since I'm not a physics phD, I'm still laboring with the notion that nothing is faster than the speed of light. If that is true, how can the universe be expanding faster than that?

Thanks for any answers.

This question is even better! And this almost drove me crazy () before I found the simple answer:

There is NO speed limit for the expansion of the universe; however every object moving inside the universe is always limited to the speed of light.​

You can read more about it here: http://www.fnal.gov/pub/ferminews/ferminews00-05-12/p5.html" .


P.S. Welcom to PF ummm!

 

[bcrowell]

1) If, at the time of the big bang, the entire universe was in, say, maybe a little ball, maybe the size of a baseball, or golf ball, or smaller like a grape or my brain (okay nothing's that small),

We don't know whether the universe is finite or infinite. We have a FAQ entry on that topic: https://www.physicsforums.com/showthread.php?t=506986

then what was outside that little ball? What did the parts or gas or whatever, that was in the little ball of universe, expand into? Whatever it expanded into, obviously had to be outside the little ball of universe.

Even if it's finite, it doesn't have an edge; it wraps around.

http://www.astro.ucla.edu/~wright/cosmology_faq.html#XIN

2) Since I'm not a physics phD, I'm still laboring with the notion that nothing is faster than the speed of light. If that is true, how can the universe be expanding faster than that?

We have a FAQ entry on that:
https://www.physicsforums.com/showthread.php?t=508610

 

[bcrowell]

Since this thread dates back to 2006, I'm going to close it.

@ummm, if the replies you've received haven't answered your questions, please feel free to open another thread.