the universe is not expanding!!! ? ? ? - Page 3

yawyaw · #61 (**permalink**) 27-April-2008, 10:27 PM

Quote:

Originally Posted by czeslaw

The gravity energy is negative if you calculate it from an infinity to a certain Radius. It means a supply of the Dark Energy from outside of the Observable Universe.

The Dark Energy is supplied by the vector gravitational energy, mcv. The real gravity energy -mu/R is attractive (centripetal) the vector gravity energy,mcv is repulsive cmDel.v = -cmv/R cos(g). What is being called Dark Energy is the vector energy of gravity, mcv. The v=sqrt(GM/R). Newton and Einstein did not include the vector gravity energy. Is there a problem in conceiving of a vector energy like mcv? There is no need to look outside the Observable Universe for the "Dark Energy".

czeslaw · #62 (**permalink**) 28-April-2008, 06:37 AM

Quote:

Originally Posted by yawyaw

The Dark Energy is supplied by the vector gravitational energy, mcv. The real gravity energy -mu/R is attractive (centripetal) the vector gravity energy,mcv is repulsive cmDel.v = -cmv/R. What is being called Dark Energy is the vector energy of gravity, mcv. The v=sqrt(GM/R). Newton and Einstein did not include the vector gravity energy. Is there a problem in conceiving of a vector energy like mcv? There is no ned to look ouutside the Observable Universe for the "Dark Energy".

I agree that potential gravitational energy has a component of vector (covariant ?) and it is repulsive kinetic energy. It is perfect balanced in the Black Hole, so the overdense singularity does not exists.

The problem is that Black Hole remains with a constant Radius if the Energy is not supplied fro outside. The BH grows when the total energy is supplied from outside.
Dark Energy (vector gravity energy) prevents a collapse of the Black Hole but if it is supplied from outside BH may grow like our Observable Universe and even accelerate.

The repulsive component vector of the gravitational energy is very important. I wrote about it in my website http://www.blackhole.glt.pl/

HypothesisTesting · #63 (**permalink**) 29-April-2008, 02:56 PM

Quote:

Originally Posted by Bob Angstrom

It is impossible to get a triangulation on the perturbations of the CMBR so its distance remains strictly theoretical.

You do make a good point here, which I agree with. The CMBR is pure blackbody without any spectral lines in it, so getting the redshift is probably impossible.

However, you do also have to explain another piece of evidence: quasars. These are clearly grouped about 10-13 billion light years away, and they have a good measure of the redshift/distance for these. These are thought to be energetic early phases in galactic evolution. In steady state theory, these would be spread out over 3-dimensions and not grouped at this distance which is clearly coincident with the early part of universe.

Jim · #64 (**permalink**) 29-April-2008, 09:03 PM

I have closed two kinds of expansion. as it seems to cover much the same ground as this thread. Let's keep discussion of the topic here.

tommac · #65 (**permalink**) 30-April-2008, 02:06 AM

I dont understand how you can claim that space just starts appearing ...

also do you claim that the universe is expanding constantly in all directions
If so do you think gravity plays a role in the expanding of space?

Jim · #66 (**permalink**) 30-April-2008, 12:41 PM

Quote:

Originally Posted by tommac

I dont understand how you can claim that space just starts appearing ...

But, space is nothing. Having more nothing appear does not violate any laws of physics as we know them.

(Okay, not really "nothing." It's more a sea of virtual particles, but since they are virtual they don't really exist, so... nothing. The Universe can be so Zen.)

Let's try a different balloon analogy...

Take an empty balloon. The wall of the balloon represents the edge of the universe; "beyond here be dragons," as in those inside the balloon have no idea what exists outside the balloon.

Blow a little air into the balloon and seal it closed.

You have now created a universe. It has a certain volume and contains a finite number of particles.

Now, place that balloon into a vacuum chamber. (Remember, what is inside the balloon doesn't know this is happening.) Make a vacuum around the balloon. It expands.

The volume of the balloon - the space inside it - expands, but the number of particles does not. You have not created (or added) any new particles, but the balloon is larger.

That's sort of what is happening to our Universe. Space is expanding, but the number of particles is the same. Literally nothing is being created.

tommac · #67 (**permalink**) 30-April-2008, 02:26 PM

This analogy is way too simple and in its simplicity it lacks to explain what is really happening.

Firstly when you expand the balloon. The real distance between particles move apart. Particles can only move at the speed of light? So in your baloon analogy if you expanded the baloon at the speed of light ... particles would at the max velocity of the speed of light rush towards the vacuum you have created. You simplified example does not account for super-luminal expansion.

Quote:

Originally Posted by Jim

But, space is nothing. Having more nothing appear does not violate any laws of physics as we know them.

(Okay, not really "nothing." It's more a sea of virtual particles, but since they are virtual they don't really exist, so... nothing. The Universe can be so Zen.)

Let's try a different balloon analogy...

Take an empty balloon. The wall of the balloon represents the edge of the universe; "beyond here be dragons," as in those inside the balloon have no idea what exists outside the balloon.

Blow a little air into the balloon and seal it closed.

You have now created a universe. It has a certain volume and contains a finite number of particles.

Now, place that balloon into a vacuum chamber. (Remember, what is inside the balloon doesn't know this is happening.) Make a vacuum around the balloon. It expands.

The volume of the balloon - the space inside it - expands, but the number of particles does not. You have not created (or added) any new particles, but the balloon is larger.

That's sort of what is happening to our Universe. Space is expanding, but the number of particles is the same. Literally nothing is being created.

NEOWatcher · #68 (**permalink**) 30-April-2008, 05:08 PM

Quote:

Originally Posted by tommac

This analogy is way too simple and in its simplicity it lacks to explain what is really happening.

That's why it's an analogy...
Besides, it addressed ONE issue you brought up...

Quote:

I dont understand how you can claim that space just starts appearing ...

...and I feel it addressed that nicely. It was about creating space... not an explaination on the expansion of the universe (although some other parallels may also apply).

tommac · #69 (**permalink**) 30-April-2008, 07:53 PM

Quote:

Originally Posted by NEOWatcher

That's why it's an analogy...
Besides, it addressed ONE issue you brought up...

...and I feel it addressed that nicely. It was about creating space... not an explaination on the expansion of the universe (although some other parallels may also apply).

You didnt create space. You merely moved the boundary. Are you saying that in the universe the boundary is the thing that is moving and things have a tendency to move towards the extended boundary?

I think I see where you want to go with the analogy but again it is too simple to explain the topic.

The anology does not work well to describe the situation we are debating.

Jim · #70 (**permalink**) 01-May-2008, 12:42 PM

Quote:

Originally Posted by tommac

You didnt create space. You merely moved the boundary. Are you saying that in the universe the boundary is the thing that is moving and things have a tendency to move towards the extended boundary?

I think I see where you want to go with the analogy but again it is too simple to explain the topic.

The anology does not work well to describe the situation we are debating.

Yeah, apparently far too simple.

Yes, you are "creating space." What do you think space is? It is "nothing." It is the distance between things.

And, yes, the "boundary" is moving. That's what happens when the box grows; the sides of the box move outward.

And, yes, things tend to "move toward" the "boundary" as the "box" grows. Everything moves away from everything else.

tommac · #71 (**permalink**) 01-May-2008, 03:37 PM

Quote:

Originally Posted by Jim

Yeah, apparently far too simple.

Yes, you are "creating space." What do you think space is? It is "nothing." It is the distance between things.

And, yes, the "boundary" is moving. That's what happens when the box grows; the sides of the box move outward.

And, yes, things tend to "move toward" the "boundary" as the "box" grows. Everything moves away from everything else.

Yes I get this ... and I get the portion of the analogy that was congruent with the theory.

However the piece that is being debated is really not addressed. That part is how does a galaxy receed away from us at speeds greater than the speed of light.

Lets take the baloon thing. You move the boundary away at 5x the speed of light would the particles also move away from each other at all points at 5x the speed of light? I dont think so ... they would move towards the new space ( towards the vacuum ) at a maximum speed slower than the speed of light. While after the particles moved to their new place there would be more space in between ... it was because the particle moved away ... not because new space was introduced.

I think we agree 100% except for the intracacies and details ... neither of which are addressed by this analogy. right?

NEOWatcher · #72 (**permalink**) 01-May-2008, 04:39 PM

Quote:

Originally Posted by tommac

...However the piece that is being debated is really not addressed. That part is how does a galaxy receed away from us at speeds greater than the speed of light...

For that piece, you need to ignore the balloon thing.

The only galaxies receeding faster than the speed of light, are outside our realm of space-time. For any object in that galaxy's space time, it is not traveling faster than light speed.

Any observations of space-time can only be made within the radius of observer's detection of space-time and not beyond. There is no outside observer.

Quote:

Originally Posted by tommac

...I think we agree 100% except for the intracacies and details ...

Knowledge is not a compromise...

tommac · #73 (**permalink**) 01-May-2008, 07:50 PM

Quote:

Originally Posted by NEOWatcher

The only galaxies receeding faster than the speed of light, are outside our realm of space-time. For any object in that galaxy's space time, it is not traveling faster than light speed.

Is that true? I thought the whole ant and the rope thing says that we can still see galaxies that are receeding away from us faster than the speed of light ... it just takes super long for the light to get to us.

NEOWatcher · #74 (**permalink**) 01-May-2008, 07:57 PM

Quote:

Originally Posted by tommac

Is that true? I thought the whole ant and the rope thing says that we can still see galaxies that are receeding away from us faster than the speed of light ... it just takes super long for the light to get to us.

In a way...
Yes; they are receeding away from us faster than light NOW.
But; we are seeing them the way they were in the past before they went past the boundary of our space time. Eventually; they* will redshift completely away from our view.

*they... as in what we currently see as the galaxy.

tommac · #75 (**permalink**) 01-May-2008, 08:04 PM

Quote:

Originally Posted by NEOWatcher

In a way...
Yes; they are receeding away from us faster than light NOW.
But; we are seeing them the way they were in the past before they went past the boundary of our space time. Eventually; they* will redshift completely away from our view.

*they... as in what we currently see as the galaxy.

Sorry to go off topic on this ... but cant a photon of light that is sent now from a galaxy that is currently receeding faster than the speed of light eventually make it to us? Based on the ant and the rope?

grant hutchison · #76 (**permalink**) 01-May-2008, 08:08 PM

Quote:

Originally Posted by NEOWatcher

In a way...
Yes; they are receeding away from us faster than light NOW.
But; we are seeing them the way they were in the past before they went past the boundary of our space time. Eventually; they* will redshift completely away from our view.

We can see galaxies that are "now" and always have been receding faster than light. I've just quoted Lineweaver & Davis on this topic on another thread:

Quote:

One might conclude that the light beyond the Hubble distance would never reach us and that its source would be forever undetectable. But the Hubble distance is not fixed, because the Hubble constant, on which it depends, changes with time. In particular, the constant is proportional to the rate of increase in the distance between two galaxies, divided by that distance. (Any two galaxies can be used for this calculation.) In models of the universe that fit the observational data, the denominator increases faster than the numerator, so the Hubble constant decreases. In this way, the Hubble distance gets larger. As it does, light that was initially just outside the Hubble distance and receding from us can come within the Hubble distance. The photons then find themselves in a region of space that is receding slower than the speed of light. Thereafter they can approach us. The galaxy they came from, though, may continue to recede superluminally. Thus, we can observe light from galaxies that have always been and will always be receding faster than the speed of light. Another way to put it is that the Hubble distance is not fixed and does not mark the edge of the observable universe.

Grant Hutchison

speedfreek · #77 (**permalink**) 01-May-2008, 08:08 PM

Subjects that may be relevant to this issue.

Cosmological Horizons: The Hubble Sphere, The Cosmological Event Horizon, The Particle Horizon

Simultaneity: The general relativistic problem of assigning a time function to a congruence of timelike curves.

John Mendenhall · #78 (**permalink**) 01-May-2008, 08:37 PM

Quote:

Originally Posted by grant hutchison

We can see galaxies that are "now" and always have been receding faster than light. I've just quoted Lineweaver & Davis on this topic on another thread:Grant Hutchison

Well, that hurts my head to think about it. But I agree. Thanks for the link, Grant.