How is space expanding ?

[island]

The viewpoint that the universe is expanding may not need to be the case at all' date=' it may be an illusion created by our universal motion.

 

This is similar to optically looking through a telescope, if you look through the correct way everything looks magnified, turn it around and everything looks smaller than it is.

 

Space-time is the carrier of all light and gravity can create a lense effect for light.

 

Maybe looking in the direction of where we came from, everything seems to come from a single point, and when we look into the direction of where we are going maybe everything looks infinately large.

 

This viewpoint is more likely to be realistic than, the viewpoint where we all miraculously exploded out of a pinhead. For this reason my mind still remains open in this area.

 

Maybe space-Time is not expanding but just in motion, giving us the illusion of an expanding universe.

 

I am interested in you comments..

 

Signed

SpaceTime[/quote']

 

No "pinhead"... per the physics that I've previously given, since tension between the vacuum and ordinary matter increases when you make particles from Einstein's vacuum energy. Eventually, tension will become so great that the forces will be compromised and it'll blow... again.

 

That also elimnates the need for inflationary theory, since the universe already has volume when a big bang occurse, and it also resolves the flatness problem since the charateristics of this universe will be "convolved" into the next, just like the last one... so the next one will necessarily be flat too.

 

Not to mention the matter/antimatter asymmetry... did somebody mention "causality"... ? ;-)

[SpaceTime]

Island,

Please learn to spell, I had to read you several times to properly understand what you were trying to say..

 

Where did the volume come from, and isn,t a vacuum just the absence of gas atoms, what created the volume in the first place? the empty space in your head? Come how can the universe come from nothing and go back to nothing or are you clutching at straws here?

 

Relax Island, this is a very contraversial subject and I do have an open mind. Do You?

 

If somebody says jump off the Sydney harbour bridge like the rest of us, remember you don't have to do it, You do have a mind of your own, and you are entitled to use it.

 

Thanks for your comments anyway.

 

Signed

SpaceTime

[island]

lol... what a dink

 

contraversial

 

 

 

 

... and learn how to spell "harbor" right-n-proper like us yankee Sepo's do... mate...

[SpaceTime]

Taught proper english in England, born in Birmingham UK, Harbour has a U in it.

 

SpaceTime

[BlackHole]

The question "how is space expanding?" or "what is space expanding into?" is not only sophisticated but also tricky because it depends on two things: 1) what is meant by space and 2) how we measure distances.

 

Generally, a space is a set with some additional structure. Important is to realize that the distance in the Riemannian metric is the one which is growing.

[island]

Let's go back to Ned Wright's excellent treatment of this:

http://www.astro.ucla.edu/~wright/cosmo_constant.html

 

Vacuum Energy Density, or How Can Nothing Weigh Something?

 

Recently two different groups have measured the apparent brightness of supernovae with redshifts near z = 1. Based on this data the old idea of a cosmological constant is making a comeback.

 

Einstein Static Cosmology

 

Einstein's original cosmological model was a static, homogeneous model with spherical geometry. The gravitational effect of matter caused an acceleration in this model which Einstein did not want, since at the time the Universe was not known to be expanding. Thus Einstein introduced a cosmological constant into his equations for General Relativity. This term acts to counteract the gravitational pull of matter, and so it has been described as an anti-gravity effect.

 

Why does the cosmological constant behave this way?

 

This term acts like a vacuum energy density, an idea which has become quite fashionable in high energy particle physics models since a vacuum energy density of a specific kind is used in the Higgs mechanism for spontaneous symmetry breaking. Indeed, the inflationary scenario for the first picosecond after the Big Bang proposes that a fairly large vacuum energy density existed during the inflationary epoch. The vacuum energy density must be associated with a negative pressure because:

 

The vacuum energy density must be constant because there is nothing for it to depend on.

 

If a piston capping a cylinder of vacuum is pulled out, producing more vacuum, the vacuum within the cylinder then has more energy which must have been supplied by a force pulling on the piston.

 

If the vacuum is trying to pull the piston back into the cylinder, it must have a negative pressure, since a positive pressure would tend to push the piston out.

 

The magnitude of the negative pressure needed for energy conservation is easily found to be P = -u = -rho*c^2 where P is the pressure, u is the vacuum energy density, and rho is the equivalent mass density using E=m*c^2.

 

But in General Relativity, pressure has weight, which means that the gravitational acceleration at the edge of a uniform density sphere is not given by

 

g = GM/R^2 = (4*pi/3)*G*rho*R

 

but is rather given by

 

g = (4*pi/3)*G*(rho+3P/c^2)*R

 

Now Einstein wanted a static model, which means that g = 0, but he also wanted to have some matter, so rho > 0, and thus he needed P < 0. In fact, by setting

 

rho(vacuum) = 0.5*rho(matter)

 

he had a total density of 1.5*rho(matter) and a total pressure of -0.5*rho(matter)*c^2 since the pressure from ordinary matter is essentially zero (compared to rho*c^2). Thus rho+3P/c^2 = 0 and the gravitational acceleration was zero,

 

g = (4*pi/3)*G*(rho(matter)-2*rho(vacuum))*R = 0

 

allowing a static Universe.

 

Einstein's Greatest Blunder

 

However, there is a basic flaw in this Einstein static model: it is unstable - like a pencil balanced on its point. For imagine that the Universe grew slightly: say by 1 part per million in size. Then the vacuum energy density stays the same, but the matter energy density goes down by 3 parts per million. This gives a net negative gravitational acceleration, which makes the Universe grow even more! If instead the Universe shrank slightly, one gets a net positive gravitational acceleration, which makes it shrink more! Any small deviation gets magnified, and the model is fundamentally flawed.

 

In addition to this flaw of instability, the static model's premise of a static Universe was shown by Hubble to be incorrect. This led Einstein to refer to the cosmological constant as his greatest blunder, and to drop it from his equations. But it still exists as a possibility -- a coefficient that should be determined from observations or fundamental theory.

[island]

Okay, now let's look at Ned's example of Einstein's vacuum in a jar again, because we can very simply prove that the vacuum does *not* runaway during expansion if particle creation is the cause:

 

If a piston capping a cylinder of vacuum is pulled out, producing more vacuum, the vacuum within the cylinder then has more energy which must have been supplied by a force pulling on the piston.

 

If the vacuum is trying to pull the piston back into the cylinder, it must have a negative pressure, since a positive pressure would tend to push the piston out.

 

Okay, the energy density of Einstein's vacuum is -- rho(vacuum)=0.5*rho(matter), so what happens to the vacuum if we get into the jar and squish this energy down over a finite region of space, until we have enough of it to achieve positive matter density?

 

1) You achieve positive gravitational curvature, and mass as well.

 

2) You have rarefied the vacuum, so negative pressure increases, and if there were no walls to contain it... ?...

 

3) The increase in mass energy is offset by the increase in negative pressure, so the vacuum does *not* runaway, as tension between the vacuum and ordinary matter grows, instead.

 

4) Eventually the forces will be compromised... and then what?

 

 

hint:

BOOM!!!

 

 

Guess what that does to Dirac's hole theory if his "sea of electrons" has negative pressure until they get condensed to equal the matter density... ?...

[BlackHole]

Halton Arp says that redshift is not a reliable distance indicator and that some redshifts might be intrinsic. Arp discovered, from photographs and spectra with the big telescopes, that many pairs of quasars ("quasi-stellar objects") which have extremely high redshift z values (and are therefore thought to be receding from us very rapidly - and thus must be located at a great distance from us) are physically connected to galaxies that have low redshift and are known to be relatively close by.

 

Allessio Notari believes that Friedman's equation is not suitable at very great distances (or at late times).

 

http://arxiv.org/PS_cache/astro-ph/pdf/0503/0503715.pdf

 

I think the CMB could be:

 

1) the local ground-state of the quantum vacuum

 

2) the polar opposite of gravity

 

I hope the 2nd year WMAP data will be released until 2006. The longer the release is delayed, the more I suspect that the delay is due to a "problem" with the magnitude of the small angle anisotropies.

[Spyman]

I think that it does if you study it, since negative pressure increases as the vacuum expands.

My question goes deeper than that. Ned Wright doesn't explain how the negative pressure of vacuum is able to grip matter and push it away from us, (gravity), faster than the speed of light. Space has no friction.

I know that if strong enough it of course can and that the force of gravity from very distant galaxies is very very small, but still to defeat that the force must have a "grip". Any force must have a direction, strengh, source and a point where it acts.

Where does this force of negative pressure act on matter ?

[Spyman]

This is because the matter furthest from the centre of the universe has the greatest kinetic energy and that closest has the least.

How did the matter furthest from the centre get greater kinetic energy than that closest ?

How can the matter furthest have so high kinetic energy that they moves away from us faster than the speed of light ?

Where did this kinetic energy come from and how can it grip the matter ?

[ed84c]

Is this kinetic energy not from the big bang?

[Spyman]

The viewpoint that the universe is expanding may not need to be the case at all' date=' it may be an illusion created by our universal motion.

 

This is similar to optically looking through a telescope, if you look through the correct way everything looks magnified, turn it around and everything looks smaller than it is.

 

Space-time is the carrier of all light and gravity can create a lense effect for light.

 

Maybe looking in the direction of where we came from, everything seems to come from a single point, and when we look into the direction of where we are going maybe everything looks infinately large.

 

This viewpoint is more likely to be realistic than, the viewpoint where we all miraculously exploded out of a pinhead. For this reason my mind still remains open in this area.

 

Maybe space-Time is not expanding but just in motion, giving us the illusion of an expanding universe.[/quote']

Big Bang theory and the expansion could be wrong but the Universe doesn't look bigger in one direction and smaller in another.

 

The redshift from distant galaxies is not due some magnified effect of gravity, it is a doppler effect either caused by expansion of the Universe faster than the speed of light or matter moving away faster than the speed of light or an illusion caused by some yet unknown cosmic effect which are streaching the light, not magnifying it.

 

We, (matter), are in motion in Space-Time, Space-Time is likely not.

[Spyman]

The question "how is space expanding?" or "what is space expanding into?" is not only sophisticated but also tricky because it depends on two things: 1) what is meant by space and 2) how we measure distances.

 

Generally' date=' a space is a set with some additional structure. Important is to realize that the distance in the Riemannian metric is the one which is growing.[/quote']What is a "Riemannian" metric ?

 

Oups ! Nevermind, I found Your link in an later post, which explains it.

[Spyman]

Halton Arp says that redshift is not a reliable distance indicator and that some redshifts might be intrinsic. Arp discovered' date=' from photographs and spectra with the big telescopes, that many pairs of quasars ("quasi-stellar objects") which have extremely high redshift z values (and are therefore thought to be receding from us very rapidly - and thus must be located at a great distance from us) are physically connected to galaxies that have low redshift and are known to be relatively close by.

 

Allessio Notari believes that Friedman's equation is not suitable at very great distances (or at late times).

 

http://arxiv.org/PS_cache/astro-ph/pdf/0503/0503715.pdf[/quote']Interesting link and as sad earlier it explains what a "Riemannian" metric is.

 

But it doesn't answere my question how the expansion of space can grip matter and bring it with it ?

(Just lowers the value of the speed and removes the acceleration.)

 

It also raises the question how to explain the high values of redshift if they are not caused by speed.

[Spyman]

Is this kinetic energy not from the big bang?

I thought the Big Bang was an explosion of space everywhere, how did different matter get different KE and how did the streaching of space during BB grip matter to be able to transform BB energy to KE and bring matter with it ?

 

I was asking edicius to clearify and maybe You should read his post to.

(Which in fact also was an answer to my question to Johnny5.)

[ed84c]

I had read his post, but you were asking were the KE came from?

[Spyman]

I had read his post, but you were asking were the KE came from?

Well if I am not totally misinterpreter the Big Bang theory and the balloon analogy than all matter should receive equally much KE from BB.

So if edicius think they received different KE it might be from somewhere else, BB is not mentioned in his post, or where did the difference came from ?

 

Maybe edicius misinterpreter my question to Johnny5 and tries to clarify the balloon analogy to me ?

(Which I am not asking for.)

[island]

My question goes deeper than that. Ned Wright doesn't explain how the negative pressure of vacuum is able to grip matter and push it away from us' date=' (gravity), faster than the speed of light. Space has no friction.

Where does this force of negative pressure act on matter ?[/quote']

 

Well, maybe Ned didn't directly answer your question in so many words, but the answer is there if you study it carefully:

 

Negative pressure still has postive energy density, so a universe that has a predominant expansive tendency also has negative gravitational curvature, which causes matter to diverge.

 

That means that the gravity of the vacuum "pushes matter away from us"... but I have no idea why you think that this process *currently* exceeds the speed of light.

[island]

I couldn't help but notice, and now I can't get over how awkward this looks, and I wanted to explain that it was not intended as an insult:

 

"i" wrote:

No "pinhead"... per the physics that I've previously given

 

I simply meant to address this point:

 

SpaceTime wrote:

This viewpoint is more likely to be realistic than, the viewpoint where we all miraculously exploded out of a pinhead.

 

I should have said something like... 'No "pinhead" necessary'... or something that appeared less insulting than the way that it came out, but it honestly wasn't my intent to call spacie a pinhead...

 

On the other hand... calling him a "dink"... was quite appropriate under the latter circumstances... heheh

[chatlack]

Its possible that space could be anything from next dimension. It can be a little hard to explain for me. But i will give it a try.

Think that we are not living on earth, we are living on one of the electrons of an atom. Atoms create a universe with many of them. This is solar system. Then solar systems create a new world with many of them. And so on...

 

This may pass for our cells : Our cells create a universe (us , their country maybe) while our cells are made of systems inside them. I think it maybe the answer for the universe (and why of existance) . Think that also we (cells made us work) are a universe with our nations. (Its a absolute truth that our body's existing reason is the same reason of our nations existence (also national feelings))

 

Can anybody discuss it?? (As Im saying these I do not believe them but they seem to be one of the logical answers)(Personal thoughts- all rights reserved )

[Ophiolite]

I hate to be the first to break it to you, but almost everybody who thinks, has at sometime pondered the atom/solar system parallel. When you look at it more closely the comparisons break down.

I once drafted a short SF story where quantum effects occured on a macroscopic level. It was crap, and fortunately its waveform collapsed on a fire.

[island]

The only truly universal pattern that I've ever found to extends to all *levels*... is for obvious good reason... a layers theory.

 

Patterns being the essence of all math and physics, this "universatility" necessarily defines a ToE, which extends teleologically right across the philosophical and metaphyical realm, and into the reality of our everyday lives.

 

The yin-yang is one philosophical example of this, because *related* layers oppose each other relatively or *complimetarily*.

 

Matter/Antimatter symmetry examples the literal relevance of this.

[bascule]

The only truly universal pattern that I've ever found to extends to all *levels*... is for obvious good reason... a layers theory.

 

Patterns being the essence of all math and physics' date=' this "universatility" necessarily defines a ToE, which extends teleologically right across the philosophical and metaphyical realm, and into the reality of our everyday lives.

 

The yin-yang is one philosophical example of this, because *related* layers oppose each other relatively or *complimetarily*.

 

Matter/Antimatter symmetry examples the literal relevance of this.[/quote']

 

I think a better example of this would be the open and closed branes which in theory compose all of reality

[island]

Don't branes come in layers?...

[Spyman]

Well' date=' maybe Ned didn't directly answer your question in so many words, but the answer is there if you study it carefully:

 

Negative pressure still has postive energy density, so a universe that has a predominant expansive tendency also has negative gravitational curvature, which causes matter to diverge.

 

That means that the gravity of the vacuum "pushes matter away from us"... but I have no idea why you think that this process *currently* exceeds the speed of light.[/quote']Negative gravity, Hmm, I will consider the idea...

 

The speed of the expansion is measured by the redshifts of the light from distant stars.

 

Link to thread "Space expanding FTL": http://www.scienceforums.net/forums/showthread.php?t=9693

 

Quote from a small part of a good post by Martin in that thread:

it is not unusual for astronomers to observe galaxies which were receding away from us faster than the speed of light at the time when they emitted the light which is now reaching us

And here are a link to Ned Wright's own online cosmology calculator: http://www.astro.ucla.edu/~wright/CosmoCalc.html