The Universe: Finite or Infinite?

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Discussion Overview

The discussion centers around the question of whether the universe is finite or infinite, exploring implications of both possibilities and the conceptual challenges they present. Participants engage with theoretical aspects, cosmological models, and the philosophical implications of these ideas.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants propose that a finite universe does not necessarily imply a "beyond," using analogies like a ring or a spherical surface to illustrate boundaryless finite spaces.
  • Others argue that the Big Bang theory does not definitively state whether the universe began as finite or infinite, suggesting that popular interpretations may mislead the public.
  • There is mention of ongoing controversy among cosmologists regarding the finite versus infinite nature of the universe, with some preferring infinite models for mathematical simplicity.
  • Participants note that observational data is currently consistent with both finite and infinite models, and caution against making assumptions that could lead to circular reasoning.
  • One participant expresses difficulty in visualizing abstract concepts like a finite volume boundaryless space, indicating a personal struggle with the implications of these models.
  • Another participant challenges the idea that a positively curved universe must be finite, suggesting that the relationship between curvature and finiteness is not straightforward.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the universe is finite or infinite, and multiple competing views remain. The discussion reflects a range of interpretations and conceptual challenges without resolution.

Contextual Notes

Limitations include the dependence on definitions of curvature and finiteness, as well as unresolved mathematical implications of different cosmological models. The discussion highlights the complexity of interpreting observational data in the context of these theories.

  • #151
cragar said:
thanks

You're welcome.

(And remember Wikipedia did all the pictures and most of the facts. :wink:)
 
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  • #152
mattex said:
OK, please let me begin by declaring that, YES, I have read around this topic, but I am still stumped.

It continually plagues me. I even had a friend blurt out of the blue the other day, "What's with the universe? Does it just keep on going forever? Or does it stop? If so, what's beyond it?"

The answer to your question is another question. Who are you? The Universe exists inside you. The Keys.Maharaji.net should help if you want to pursue this in an experiencial way. This is a paradox and can only be understood by experiencing it.
 
  • #153
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  • #154
DevilsAvocado said:
Who are you? You are clearly at the wrong place. Please read the https://www.physicsforums.com/showthread.php?t=5374", or return to Maharaji.net.

If you read the initial question, you will realize that the person asking the question was in the wrong place to ask what he really wanted to know. I didn't mean to offend, only trying to be helpful.
By the way, I'm not from M.net nor am I selling anything.
Original poster was Mattex. Also, refer to Mattex post dated May 15, 2007.
 
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  • #155
rfstanton said:
If you read the initial question, you will realize that the person asking the question was in the wrong place to ask what he really wanted to know.


Well, I think you’ve misunderstood the whole thing, and referring to Mattex doesn’t make your case any better:

"I'm not interested in an artificial concept, I'm only interested in the Reality of the whole situation."

Mattex is spot on, at the right place and time. You are not.

Prem Rawat (Maharaji) has absolutely nothing to do with real science, physics and cosmology. This fleshy Guru is a faked crackpot (as most of them are), chasing easy money in the west. He promotes peace and understanding within, but when the Guru Maharaji got http://en.wikipedia.org/wiki/Divine_Light_Mission#Detroit_incident".

"The Lord of the Universe" ... ??
https://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/VPehWlDFRcE&hl=sv_SE&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/VPehWlDFRcE&hl=sv_SE&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
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  • #156
The universe is infinite. Becouse Time is infinite. The universe Stays in the "present" becouse (Time and Anti-Time) work to move time into the (future and the past) working together. So the True Past is always the moment of creation, and the true future is always the moment of destruction. Meaning one second ago the universe was created, and one second from now the universe is destroyed.

No worrys though the universe stays in the (Present).

But just to add. There really is only one Particle, and one anti particle present in the whole universe. And Time and Anti-Time' Past and Future only holds a single Particle, But this results in an infinite amount of particles in the present.

So in a strange way the answer is kinda both. it just depends on how you preceive time.

Sorry it is a little confusing when i try to type it out i explain it better verbally.

just think of the laws of motion. every action has a equel and opposite reaction. Same applys to time as well. When something moves forward in time, Anti time moves time backwards to work to keep time in the present. So if you are riding a beam of light you are indeed Speeding through time, but anti time is also working to keep you in the present. this is why nothing can go faster than this point, except time time is as fast as light also. then again i can't prove it.
 
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  • #157
DevilsAvocado said:
Well, I think you’ve misunderstood the whole thing, and referring to Mattex doesn’t make your case any better:

"I'm not interested in an artificial concept, I'm only interested in the Reality of the whole situation."

Mattex is spot on, at the right place and time. You are not.




What is "real"? The art or the artist? If the art is perceptual, that does not change the rules or our science and the way we practice it, only the way we understand and approach it. Possibly with a little more respect for the artist and the art.

The way it all makes sense to me, time and space are continuum and the present time and space are all that we exist in. The past is only history, the future, only possibility. Present is what we are stuck with. Lucky us!

"All the world's a stage, and we are merely actors." Shakespeare, I think.
 
  • #158
LoreSpade said:
The universe is infinite. Becouse Time is infinite.

None can prove this at this stage, not even the 'peace loving' "Lord of the Universe" - Prem Rawat Maharaji.

LoreSpade said:
There really is only one Particle, and one anti particle present in the whole universe.

This is horrible wrong.
 
  • #159
rfstanton said:
What is "real"?

Well what’s real is for example the fact that Prem Rawat (Maharaji) is a faked crackpot, talking about love, peace and understanding – and at the same time almost kill people who he dislike, with an iron bar.

This is real and can be proven.

Art is about emotions and real science is about hard and provable facts – two completely different things.
 
  • #160
Back to the art and artist concept. If the physical universe is merely the artwork of the artist, then the question of whether the universe is infinite or infinite is easily answered, along with a lot of other questions. Like I said before, this view does not change the way we need to practice science, only the way we view and approach it. It seems that we exist in 2 dimensions simultaneously. One is experienced with our heart, and the other with our mind. Which one is "real" and which is the "illusion" leads us to which one (heart or mind) to give precedence. Morality gets into the picture, but I don't think anything we do should be totally the venue of the mind or the heart, for this phenomenon is what makes us what we are. This will be my last post on this thread. Just some of my stupid ideas. At least that's what my wife says.
 
  • #161
Wanting the universe to be infinite for philosophical, aesthetic, or artistic reasons does not make it a valid assumption. There is no compelling observational evidence the universe is spatially infinite. There is overwhelming evidence it is temporally finite.
 
  • #162
Does the fact that the universe is flat implies that it is infinite?
 
  • #163
I think the expansion is something hard to visualize for us. In my mind the universe is infinite but finite at one moment. As the universe expands it creates its own space inside its own 4d structure within its 2d sheet. In the same way that its predicted that if we created a universe inside our own, it would be here for an instant before expanding into its own dimensional space, and we would never see it again. They take up space defined by their own laws as it is needed.
 
  • #164
maxverywell said:
Does the fact that the universe is flat implies that it is infinite?

I think The Hubble Universe can be flat unbounded and finite.

But, there's still the question about if the Hubble Universe is embedded in a larger bulk universe; which would be difficult to imagine having an irrefrutable (sp?) end.
 
  • #165
Pjpic said:
I think The Hubble Universe can be flat unbounded and finite.

I think this is impossible, because, if I'm not mistaken, the flatness of the universe implies that it's open and unbounded and therefore it's infinite. It would be finite only if it was positively curved which is not the case (acording to the CMB). Please correct me if I'm wrong.
 
  • #166
This is getting beyond me now. But if positive means the universe contracts to a singularity and flat means it reaches a steady state, I don't see how either case changes the current condition of being finite.
 
  • #167
boy, i read thru some of this thread, and i am confused.

my understanding of the question went more along with what marcus had thought it to be.

i can't see how there could be an infinite amount of anything ?

if the universe is expanding, does that not mean there is more space now, than there was a second ago ?
 
  • #168
Any problem of infinite Universe.

1 dimension axis

---0---1----2----3-- ---n-1---n---n+1---

0 -> Earth 0 position, 1 -> 10000 kpc away galaxy, n -> n kpc away galaxy

Every interval is same speed expansion.

dv/dx=vx
v; expansion velocity, x; galaxy position
solution
ln v=x^2/2 +c
v=C e^(x^2/2)
condition x=1, v=v0 ; 10000 kpc away galaxy.
final soluton
v= v0 e^(x^2/2 - 0.5)

Problem is that the expansion speed of the far away galaxy is over the light speed.
Is it possible that galaxy speed is over the light speed?

This is a very big paradox.
 
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  • #169
maxverywell said:
Does the fact that the universe is flat implies that it is infinite?

A flat universe that is not simply connected can be finite.
physalpha said:
Problem is that the expansion speed of the far away galaxy is over the light speed. Is it possible that galaxy speed is over the light speed?

This is a very big paradox.

See

https://www.physicsforums.com/showthread.php?p=2955417#post2955417.
 
  • #170
I have been able to understand and accept that galaxies at the edge of our observable universe can recede from us at superluminous velocities, but I cannot think why they do not become infinitely massive when observed from our frame of reference. How can we apparently decide at will to no longer apply certain laws?


Also if our universe is truly infinite then galaxies an infinite number of observable universe radii away from us would be receding from us at an infinite multiple of the speed of light away from us. Either that of they all hit the pan galactic flypaper at the edge of the universe where all the black holes are :)


Another question regarding the possibility of an infinite universe; How does an infinite universe fit into an infinitesimal inflatron singularity?!
 
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  • #171
Above the light speed.
Is it possible to be particles state?
According to the uncertainty theory, at the very high speed, particles uncertainty is increased very high.
That means, the far away galaxy is very difficult to be a condensed state.
And, above the very high speed, particles existence probability is very low.
 
  • #172
No, it's impossible to move through the space with speed greater than the speed of light c (in vacuum), but space itself can expand with speed > c.
 
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  • #173
George Jones said:
A flat universe that is not simply connected can be finite.

How it can be not simply connected? Can we think of black hole as "holes" on space that make it to be not simply connected? :-p :smile:
 
  • #175
Thanks George!
 
  • #176
So

When we see the galaxy.

----Earth------------small gap light speed---------light speed -----above light speed--

----->||<-------------------->|<--------------------->|<----------------------------
============ red shift========== can not see============ never see=======
.........very small light speed...light go to the other side

visible lignt case
...O visible light
.....O infrared light
......O radio wave


Is this right?
?
 
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  • #177
I would vote for finite but at the same time have the potential to expand indefentily. So it could be a certain size but then continue to expand larger forever. Like a beach ball that you could continue to blow up larger forever. The larger the universe gets the more dark energy would end up takeing over makeing the universe expand more and more as time progresses.
 
  • #178
Chalnoth can you please help me out here:


I have been able to understand and accept that galaxies just beyond the edge of our observable universe can recede from us at superluminous velocities, but I cannot think why they do not become effectively infinitely massive due to their relative velocity to us. What am I misunderstanding here?

Also if the universe is infinite in size then due to expansion galaxies would be moving at infinite speeds away from us, which makes the above situation even more strange.

Finally if the universe is in fact infinite in size, how can an infinite universe ever be finite let alone an infinitesimal inflatron singularity?
 
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  • #179
Tried to answer the above questions myself and came across this theory that claims that even though both the universe's density (ρ) and its temperature (T) are shown to be larger in the past, it seems likely that these are purely relativistic affects and that at those times the measured values would be what they are today. Cosmological Special Relativity and Special relativity are not exclusive but work together, each being most significant under the right circumstances. Special relativity as v approaches c and Cosmological Special Relativity as t approaches τ.

http://creationwiki.org/Cosmological_relativity


This is an interesting paper discussing relativistic mass:

"We can thus tell our students with confidence that kinetic energy has weight, not just as a theoretical expectation, but as an experimental fact."

http://arxiv.org/PS_cache/gr-qc/pdf/9909/9909014v1.pdf


What is Relativistic Mass:

http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html



Is this statement correct: Most of the mass (protons and neutrons) comes from the relativitic mass of quarks.
 
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  • #180
For the most part, we don't usually consider relativistic mass in relativity any longer, just the rest mass. The relativistic mass notation was largely dropped because it caused mistakes, instead taking mass to simply mean the rest mass, and allow energy to scale with velocity instead:

E = \gamma mc^2

This doesn't go against what Carlip said, mind you, because in this formulation gravity responds to energy, not mass, and inertia is similarly a function of energy instead of mass.

How does this mesh with far-away galaxies receding at faster than the speed of light? Well, the short answer is that the energy (or relativistic mass) of an object is an observer-dependent quantity. As an observer-dependent quantity, it shouldn't be any surprise that with some particular choices of coordinate system, the result is nonsensical.

In special relativity we are protected from such difficulties by the flatness of the space-time. But with space-time curvature, velocities of far-away objects become arbitrary, and thus carry no direct physical significance.
 

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