What Is Beyond The Observable Universe?

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Discussion Overview

The discussion revolves around the nature of what lies beyond the observable universe, exploring concepts of infinity, the possibility of multiple universes, and the implications of current cosmological models. Participants engage in philosophical reasoning, theoretical implications, and speculative ideas regarding the universe's boundaries and the existence of phenomena beyond our observational limits.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Philosophical reasoning

Main Points Raised

  • Some participants question whether the universe extends infinitely or if there are boundaries beyond which lies another universe.
  • Others assert that by logical necessity, there is 'nothing' beyond the observable universe, as it is unobservable and cannot be subjected to falsifiable predictions.
  • A few participants propose that the observable universe may be part of a larger multiverse, suggesting that future advancements might allow us to observe beyond current limits.
  • There is a discussion about the implications of the inflation model, which posits that the universe is much larger than what we can observe, yet still finite.
  • Some participants express skepticism about the concept of a finite universe, questioning what lies at the 'end' and whether it could be a barrier or something else entirely.
  • Concerns are raised about the nature of existence and whether events outside our observable universe can be said to exist if they cannot be observed.
  • Participants discuss the concept of 'horizons' in cosmology, which define the limits of what can be observed due to the finite speed of light and the age of the universe.
  • One participant speculates that there may be more stars, black holes, and galaxies beyond the observable universe, suggesting that cosmic expansion prevents their effects from reaching us.

Areas of Agreement / Disagreement

Participants express a range of views, with no clear consensus on the nature of what lies beyond the observable universe. Some agree on the philosophical implications of 'nothingness,' while others propose alternative models or speculate about the existence of additional cosmic structures.

Contextual Notes

Limitations in the discussion include unresolved assumptions about the nature of the universe's boundaries, the implications of different cosmological models, and the philosophical interpretations of existence and observation.

What Is Beyond The Observable Universe?

  • Just Infinite Black Space

    Votes: 27 13.6%

  • Blacks Space Until A Different Universe

    Votes: 36 18.1%

  • Other

    Votes: 136 68.3%
  • Total voters
    199
  • #361
Jake4 said:
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!)
 
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  • #362
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?
 
  • #363
DaveC426913 said:
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.
 
  • #364
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'
 
  • #365
I like to think of the possiblity of different mathematical operators.. other than our standard +,-,÷,* .. in other universes :)
 
  • #366
Jake4 said:
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)
 
  • #367
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?
 
  • #368
Tanelorn said:
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!
 
  • #369
Tanelorn said:
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
 
  • #370
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.
 
  • #371
Trenton said:
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
 
  • #372
Trenton said:
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?
 
  • #373
'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'.
 
  • #374
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.
 
  • #375
ummm said:
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.

ummm said:
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'.
ummm said:
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.
 
  • #376
ummm said:
...
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.
 
  • #377
ummm said:
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. :smile:

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... :rolleyes: 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. :smile:

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... :blushing:

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... :rolleyes:)

ummm said:
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 (:biggrin:) 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!
 
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  • #378
ummm said:
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

ummm said:
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


ummm said:
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
 
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  • #379
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.
 

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