The Universe: Finite or Infinite?

[naeemakhtar]

re:universe:Finite or infinite.
i have gone through the all dicussion on the finiteness or infiniteness of the universe.When we talke about finiteness or infiniteness then we percieve a goematrical figure describing (length,area or volume) terms of the numbers.Whole dicussion revolves arroud some definte geomatrical figures(which maths has discoverd) to comprehend the structure of the universe,do we excuse to accept the probablity of existence of some undiscovered geomatrical figures or shapes which could have potential to explain the struture of the universe at BB(big bang) and transition in it explicitly.or Mathematics
is insufficient to cater the qustion.

 

[QuantumDream]

What a great topic and an amazing level of thought has been put into the discussion.

I tend to think the Universe does have it's limits and may have a degree of boundary outside the scope of matter verses spatial volume.

Spacial volume may be infinite, in that the room for a growing and expanding Universe may not bump into a large wall of matter to hinder it's expansion.

Matter however within this Universe does appear to be limited and finite based on the vast amount of spatial volume by which it is scattered. Matter appears finite within an infinite volume of space.

I find it hard to imagine a limit to the volume of space, but easy to imagine a limit to the length of our Universe within that infinite volume. Gravity is taking care of keeping what matter that does exist within this spatial volume some what contained.

Based on gravity, the matter in the Universe will have some type of boundary at the edge of its furthest length of expansion. What lies beyond? Empty space? The edge of another Universe? We can only imagine.

 

[DevilsAvocado]

naeemakhtar,
thanks for your thoughts.

Personally, I’m not that concerned about the 'shape' of the universe, it’s more like the 'scope' that is infinitely on my mind.
(as you can see )

 

[DevilsAvocado]

QuantumDream,

Nice and poetic thoughts, but I’m afraid I must put some 'brutal' science logic on the conclusion...

On the most basic level we could say that the universe consist of only two components: spacetime & matter (= energy), and spacetime is defined as the 'stuff' between the matter/energy.

Conclusion: No Matter = No Space

The universe is expanding, not into 'something', rather nothing...

This is the explanation from the experts.

(Even if my brain gets swollen by this into-nothing-logic )

 

[DevilsAvocado]

Einstein was the first who had realized that. For the infinite Unvierse it means that it collapses into black hole now matter how low an average density is.

Dmitry67, I’ve talked to Santa...

And he promised me a brand new Power Calculator for Christmas...

http://upload.wikimedia.org/wikipedia/en/thumb/6/6f/Powercalc.PNG/500px-Powercalc.PNG

With the new calculator, I will find time in the coming holidays to investigate infinite sets and the Schwarzschild solution, and come back with new (tiring ) questions in the beginning of the infinite year of 2010!

 

[cragar]

can this question ever really be answered?

 

[marcus]

...But, now another question pops up! In an infinite universe, with infinite matter – how can you avoid the thing from turning into a singularity immediately at t=0+1plank... Schwarzschild would go bananas??

Look at the formula for Schwarzschild raduis. Do you see something strange? r is propotional to M. Intuitively one could expect r^3 (as volume).

So yes, you must compress Earth to 6mm to make it a black hole. Now make Earth (using the same material) 10 times bigger (radius of equator). It is now 1000 times heavier, as we assume the same density, and volume increases as r^3. So Schwarzschild raduis will be 6meters. It contains 1000'000'000 more space, then before to accommodate 1000 time more mass, so the density of that object, to be converted into a balckk hole, is 1000'000 times less now!

As you see, for a constant initial density, Schwarzschild radius grows as r^3 of the object radius. So, it 8always* catches with an actual raduis! It means, that you can make a black hole of any material without compressing to - from ground, earth, air, and even interstellar gas, you just need to make a big enough volume of that material.

Einstein was the first who had realized that. For the infinite Unvierse it means that it collapses into black hole now matter how low an average density is. That is why he introduced the lambda, trying to save the Universe.

However, it is applicable to the static universe only, if Universe if expanding, then its density depends on an average density and rate of expansion. So, regrding 'why it does not form singularity immediately' - because it MUST be expanding!

Outstanding response to a frequently asked question. Expansion is the key to why the universe didn't immediately form a black hole when it was at high density, and also the key to why we don't live in a black hole with radius approximately the Hubble radius---things people often ask about. I want to keep track of this post, put it somewhere I can find it. Or maybe I will just adopt the explanation and use it myself.

 

[DevilsAvocado]

Outstanding response to a frequently asked question.

Yes, I agree. As I said earlier, this answer sends shivers down my spine. The thing that really excites me, is the fact that the "Schwarzschild radius grows as r^3 of the object radius", and this made me realize that this is (probably) inside my 'light-cone of mathematical understanding'. And it made me happy. I always thought that this kind of high-level science required (at least) differential calculus and/or integral calculus... and a lot of 'odd' symbols...

It’s been a hectic period before Christmas, but now I finally have the time too really evaluate this answer and do the math. I know it’s not that complicate (mathematically), I just need my brain to accept the 'deal' as well!

2010 is going to be a very interesting year!

 

[DevilsAvocado]

can this question ever really be answered?

Well, I don’t know if I’m the right (lay)man to give you the answer... but I’ll give it a try.

Science and technology have made tremendous progress the last century. If someone would have said in 1900 that in a hundred years – we are going to put a man on the Moon, and then send a remote-control-car to Mars, and then photograph the whole Universe when it was only 400 000 years old, from a satellite, and put the picture on the 'electronic net', so that everyone can sit at home and study the picture any time they like, etc, etc – that person would probably have been sent to a mental hospital...

No one today can say what the next hundred years will look like in science and technology (if we survive the threats against mankind). All we can do is guess that it will be astonishing.

Today: We can say that the shape of the observable universe (local geometry) limit the possibilities for the universe as a whole (global geometry). If the shape of the local geometry is spherical, then the global geometry must be finite.

Problem: Think of a football ground on earth. It seems pretty flat, right? But we do know that the surface of the Earth is round, a sphere! If the local geometry is only a 'football ground' compared to the global geometry, it can be hard to realize it’s actually spherical...

Status: In 2003 (confirmed 2008), scientist studying the data from the WMAP satellite, led to the suggestion that the shape of the Universe is a Poincaré sphere. And what is a Poincaré sphere, one might ask? Well, it’s a homology sphere, also known as Poincaré dodecahedral space. And a dodecahedron looks like this;

Alternatively, "the Poincaré homology sphere can be constructed as the quotient space SO(3)/I where I is the icosahedral group" (according to Wikipedia). And a disdyakis triacontahedron, or hexakis icosahedron, looks like this;

Or, we can make it simple (I like that! ) and say – a common example of a spherical truncated icosahedron, that has full icosahedral symmetry, is a soccer ball!

Now we are back on the flat football ground again!

 

[cragar]

thanks for the response , you put a lot of work into it .

 

[DevilsAvocado]

thanks

You're welcome.

(And remember Wikipedia did all the pictures and most of the facts. )

 

[rfstanton]

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.

 

[DevilsAvocado]

Who are you?

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.

 

[rfstanton]

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.

 

[DevilsAvocado]

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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[LoreSpade]

The universe is infinate. Becouse Time is infinate. 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 infinate 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.

 

[rfstanton]

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.

 

[DevilsAvocado]

The universe is infinate. Becouse Time is infinate.

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

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

This is horrible wrong.

 

[DevilsAvocado]

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.

 

[rfstanton]

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.

 

[Chronos]

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.

 

[maxverywell]

Does the fact that the universe is flat implies that it is infinite?

 

[Eyelegal]

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.

 

[Pjpic]

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.

 

[maxverywell]

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.

 

[Pjpic]

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.

 

[Physics-Learner]

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 ?

 

[physalpha]

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.

 

[George Jones]

Does the fact that the universe is flat implies that it is infinite?

A flat universe that is not simply connected can be finite.

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.

 

[Tanelorn]

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?!

 

[physalpha]

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.

 

[maxverywell]

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.

 

[maxverywell]

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?

 

[George Jones]

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?

See

https://www.physicsforums.com/showthread.php?p=2587993#post2587993

https://www.physicsforums.com/showthread.php?p=2726707#post2726707.

 

[maxverywell]

Thanks George!