Space is not infinite.

[michel123456]

That is what Bondi called the "perfect cosmologicalrinciple". It leads to s steady state theory of cosmology as advanced by Hoyle or Bondi and Gold.

 

These theories intuitively appealing, relatively simple and wrong.

 

And to Allan Guth's Chaotic inflation Theory, which still stands.

 

There is no doubt the Perfect Cosmological Principle MUST be correct. Considering otherwise would throw yoursef in the bottom of my infinitely deep consideration well.

Edited April 26, 2011 by michel123456

[Spyman]

There is no doubt the Perfect Cosmological Principle MUST be correct.

According to observation time flows and things change, everything is affected and nothing remains the same.

 

We don't have knowledge of anything able to continously restore or keep the Universe in a static steady state.

 

Without a reasonable explanation of how the Universe can avoid changing I am in serious doubt of such claims.

 

Any observational evidence or good logical arguments other than your opinion that it MUST be correct?

[John Cuthber]

"There is no doubt the Perfect Cosmological Principle MUST be correct."

 

OK Michel, how come it goes dark at night?

[jamiestem]

If the universe is expanding, then it can't be infinite, can it?

[Spyman]

Try to visualize than you and your meterstick are slowly shrinking inside a huge container, thus the distances you try to measure between marks on the floor is increasing, does it make any difference whether the container is finite or infinite since the walls of the container is not moving?

 

"The metric expansion of space is the increase of distance between distant objects in the universe with time.

 

It is an intrinsic expansion—that is, it is defined by the relative separation of parts of the universe and not by motion "outward" into preexisting space. In other words, the universe is not expanding "into" anything outside of itself."

http://en.wikipedia.org/wiki/Metric_expansion_of_space

[michel123456]

Try to visualize than you and your meterstick are slowly shrinking inside a huge container, thus the distances you try to measure between marks on the floor is increasing, does it make any difference whether the container is finite or infinite since the walls of the container is not moving?

 

I totally agree but:

that is NOT what the expanding space states.

I whish it was.

What the expanding space states is that WE ARE FIXED through gravitational bounds and that the "fabric of space" is expanding.

[DrRocket]

If the universe is expanding, then it can't be infinite, can it?

 

Yes it can. Quite easily.

 

Imagine an infinite sheet of rubber. Now stretch it.

 

Or imagine an infinite sheet of paper with grid lines. Now look at it through a magnifying glass.

[michel123456]

Yes it can. Quite easily.

 

Imagine an infinite sheet of rubber. Now stretch it.

 

Or imagine an infinite sheet of paper with grid lines. Now look at it through a magnifying glass.

 

That is not easy at all.

1. I cannot imagine an infinite sheet of rubber.

2 If you stretch a very large sheet of rubber, you can do that only locally, somewhere else the sheet will contract.

3 I cannot imagine an infinite sheet of paper with grid lines.

4 are you suggesting that our observation of the expanding space is comparable to an observational deformation and not to something that actually happens?

[DrRocket]

That is not easy at all.

1. I cannot imagine an infinite sheet of rubber.

2 If you stretch a very large sheet of rubber, you can do that only locally, somewhere else the sheet will contract.

3 I cannot imagine an infinite sheet of paper with grid lines.

4 are you suggesting that our observation of the expanding space is comparable to an observational deformation and not to something that actually happens?

 

1. You need a better inagination.

 

2. Not true. Just stretch it everywhere.

 

3. See 1.

 

4. No. I am suggesting that the expansion is describable by a scale factor --- Google FLWR metric.

[michel123456]

1. You need a better inagination.

 

I can imagine a sphere of rubber. I cannot imagine an infinite sheet of rubber. From your comment I suppose you can.

[DrRocket]

I can imagine a sphere of rubber. I cannot imagine an infinite sheet of rubber. From your comment I suppose you can.

 

 

 

Yes.

 

It is just like the Cartesian plane, but stretchy.

[michel123456]

Zoup with the 2 others.

[DrRocket]

Zoup with the 2 others.

 

????????

[Spyman]

I totally agree but:

that is NOT what the expanding space states.

I whish it was.

What the expanding space states is that WE ARE FIXED through gravitational bounds and that the "fabric of space" is expanding.

First I would like to know what part of my analogy is NOT correct according to what the expanding space states? In my analogy the person is fixed to the floor by gravity and friction and it is the "fabric" of the floor that is expanding. The analogy was only ment to show that the distance to any walls don't have to influence whether marks on the floor can recede from each other or not from the viewpoint of the observer.

 

Secondly, since you seem to be arguing something entirely different than what I was trying to explain to jamiestem, I think you should mention that more clearly and not express yourself as you are presenting a valid argument against what I said. Your argument is totally irrelevant to whether the expansion of space is preventing any hypothetical infiniteness of the Universe or not.

 

Lastly I think your interpretation that we are nailed to an expanding "fabric of space" is wrong. Can you provide a quote in context with a link to the full article where it's stated that "WE ARE FIXED" to the "fabric of space"?

[michel123456]

First I would like to know what part of my analogy is NOT correct according to what the expanding space states? In my analogy the person is fixed to the floor by gravity and friction and it is the "fabric" of the floor that is expanding. The analogy was only ment to show that the distance to any walls don't have to influence whether marks on the floor can recede from each other or not from the viewpoint of the observer.

 

You wrote:

"Try to visualize than you and your meterstick are slowly shrinking inside a huge container" (emphasis mine)." I understand what you mean. IMHO it is the reverse of "the person is fixed to the floor by gravity and friction and it is the "fabric" of the floor that is expanding".

Of course, either the observator is shrinking in a huge container, either he is at a fixed scale in an expanding container, the observation will be the same. I suppose that was your meaning. But IIRC it is assumed by the entire scientific community that we are not shrinking, and that the "container" is expanding.

 

Secondly, since you seem to be arguing something entirely different than what I was trying to explain to jamiestem, I think you should mention that more clearly and not express yourself as you are presenting a valid argument against what I said. Your argument is totally irrelevant to whether the expansion of space is preventing any hypothetical infiniteness of the Universe or not.

 

I barely understand your statement but I guess you must be right. If it was irrelevant please accept my apologies.

 

Lastly I think your interpretation that we are nailed to an expanding "fabric of space" is wrong. Can you provide a quote in context with a link to the full article where it's stated that "WE ARE FIXED" to the "fabric of space"?

 

Do you ask me to provide a link where it is stated that we have a fixed size?

I found this one which says that we are not shrinking

People often assume that as space expands, everything in it expands as

well. But this is not true. Expansion by itself--that is, a coasting expansion neither accelerating nor decelerating--

produces no force. Photon wavelengths expand with the universe because, unlike atoms and cities, photons are not

coherent objects whose size has been set by a compromise among forces.

A changing rate of expansion does add a new force to the mix, but even this new force does not make objects expand or contract.

 

For example, if gravity got stronger, your spinal cord would compress until the electrons in your vertebrae reached a new

equilibrium slightly closer together. You would be a shorter person, but you would not continue to shrink. In the same

way, if we lived in a universe dominated by the attractive force of gravity, as most cosmologists thought until a few years

ago, the expansion would decelerate, putting a gentle squeeze on bodies in the universe, making them reach a smaller

equilibrium size. Having done so, they would not keep shrinking.

from Misconceptions about the Big Bang page 4 & 5 Scientific American Edited April 29, 2011 by michel123456

[Spyman]

I barely understand your statement but I guess you must be right. If it was irrelevant please accept my apologies.

No apology needed, I was only pointing out a fault in your argument and not claiming inappropriate behavior.

 

Since there seems to be some cind of misunderstanding, I will try to explain it again for you:

 

jamiestem asked: "If the universe is expanding, then it can't be infinite, can it?"

 

I described an analogy of how a container can expand from an inside view, even with infinite distant walls.

 

Can you explain how your argument affects the possibility in my analogy for the Universe to be infinite or not?

 

 

You wrote:

"Try to visualize than you and your meterstick are slowly shrinking inside a huge container" (emphasis mine)." I understand what you mean. IMHO it is the reverse of "the person is fixed to the floor by gravity and friction and it is the "fabric" of the floor that is expanding".

Of course, either the observator is shrinking in a huge container, either he is at a fixed scale in an expanding container, the observation will be the same. I suppose that was your meaning. But IIRC it is assumed by the entire scientific community that we are not shrinking, and that the "container" is expanding.

The scientific consensus is that the Universe is expanding with a scale factor changing the metric, making both observations equal.

 

"Taken together, the only theory which coherently explains these phenomena relies on space expanding through a change in metric."

http://en.wikipedia.org/wiki/Metric_expansion_of_space#Observational_evidence

 

In cosmology the scale factor tells us how much larger the Universe grows with our meterstick as reference, if the observer and his meterstick shrinks, then the Universe also gets enlarged from his view, space is expanding in comparison to how long we are defining one meter to be.

 

We don't have any absolute reference of how long one meter is from outside of the Universe and are not able to stick map pins in space and observe how the "fabric" is growing either.

 

What we do have is pieces of matter we can use as reference, both the old one meter alloy bar in France and the new definition from lightspeed are depending on things inside Universe that we have no ability to check against anything outside.

 

We also have observations of redshift from distant objects that currently only can be explained if space is expanding by a scale factor of the metric and a well working theory of Relativity that matches observation.

 

Taken together we can only conclude that space is expanding compared to our reference of the length of one meter. So in both our examples the Universe gets larger and in none of them do we shrink compared to our meterstick. Because if we really would shrink so would our meterstick, there is no inside view of the Universe differenting between the examples. Even in my analogy the person shrinks equally much as his meterstick and is not able to anyway determine that he himself is shrinking.

 

 

Do you ask me to provide a link where it is stated that we have a fixed size?

No, I wanted to know what you ment with "What the expanding space states is that WE ARE FIXED through gravitational bounds.

(I think I got it right now anyhow.)

 

 

I found this one which says that we are not shrinking

Your link is explaining how a small cosmological constant only would change our size slightly and then reach equilibrium with the other forces acting on particles, however if we find out that Dark energy is phantom like then the acceleration of expansion will eventually accelerate exponentially and finally growing strong enough to literally rip atoms apart.

 

It does not claim that the Universe is growing or that we are not shrinking in the way you seem to be insinuating.

Edited May 2, 2011 by Spyman

[Snuttifronk]

The further away a lightsource is, the more dim it gets.

 

This is due to it being obscured by for example particles floating around in space.

So the furher away something is the more particles obscures the light.

 

Even if the particles are immensly scattered it would serve as an impenetrable veil if the lightsource is far enough in the distant would it not?