This is my first post. I couldn't find the introductions section. Hope that's not a bad sign.

Greeting brodix. Welcome to BAUT. 'c' does, in a sense, increase as space expands. This does not violate GR because photons sacrifice energy [redshift] in the process. It does not violate SR because time dilation conserves the distance velocity relationship between remote observers.

Thanatos,

Does that mean redshift is due to recessional velocity, or negative curvature?

Moved from ATM section - welcome to BAUT, brodix!

Occam must be quite dizzy and his razor is reduced to a wet noodle.

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For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

Nereid,

Thanks for the direction, but I'm being somewhat leading with these questions. Dipping my toe in the water and trying to find where the members of this forum are, with regards to their adherence to the Big Bang model.
If you wish, I could offer up some thoughts on the subject. For instance, if space is expanding due to recessional velocity, does that mean that when the universe was half its present dimension, the speed of light was half as fast as it is now? Otherwise it would seem the speed of light is relative to a more stable dimension of space then that proposed by Big Bang Theory, as based on the redshift of this light.

Welcome, Brodix...

You'll find that some like balloons, some like cake and some like to have their cake and eat it. But beware, there's sharks in the water (and ducks, IIRC)...

Q: Why doesn't c increase as space expands?

A: Why should c increase as space expands?

The questions & answers are always intimately connected to the model(s) that one chooses to describe the detailed physics of the universe, as well as its expansion history (if any). So, one might legitimately answer the question with the obvious counter question. Is there some reason we should expect c to increase as the universe expands? How about c decreasing as the universe expands (which is the way it behaves in the variable speed of light cosmology, advanced primarily by João Magueijo; i.e., Albrecht & Magueijo, 1999 and citations thereto).

And what exactly do you mean by "c" anyway? Do you mean the speed of light as measured by an observer in his own frame of rest? Do you mean the speed of light as a variable in the equations of general relativity? Do you mean the speed of light as a "constant" (or variable) of proportionality between space & time? They are all different, but all perfectly valid cosmological interpretations of c.

The original question really only makes sense in the context of some cosmological model. In standard big bang cosmology there is no need for c to vary at all, so it does not. It could be variable, there is nothing about general relativity that prevents it from being variable, it's just that things are a lot easier to understand & manipulate if it is not.

So, why do you think it should be variable? And are we heading back to ATM?

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Originally the big bang model simply assumed the universe was expanding, but as galaxies were examined more closely, they were all redshifted directly away from us, with no other direction or flow, suggesting an expansion from some general region. Therefore the impression was that we were at the center of this expansion. The concept was amended to say that space itself was expanding, so that every point was receding from every other point at a rate proportional to distance and they have all started out as a singularity. My point is that the speed of light is 299,792,458 meters per second, so if space itself is expanding, and the meter is a measure of space, then it is expanding, so the speed of light should stay relative to this dimension, even though it is expanding. Of course, this would create a matrix effect and we wouldn't even be able to detect the expansion, but that is why it doesn't make sense to say that space is expanding, if our most basic measure of it is stable.

My theory is that radiation negatively curves space, just as mass positively curves space. So light which managed to travel across the universe, without falling in any gravitational wells, would have crossed a lot of negatively curved space and appear as though its source was moving away.
This idea first occured to me, many years ago, upon hearing that Omega should equal one. It seemed a convective cycle would be the most logical explanation for this. Like the diameter of both sides of the same coin being equal.
When mass collapses to a sufficent density, it ignites and radiates out the constituent energy, so if we can accept that mass causes space to be curved positively and radiation expands out from collapsed mass, wouldn't it be logical to assume that it causes space to be curved the other way?
We know mass collapses, we know it ignites and radiates out. The only part of the circle which is open is if this radiation eventually cools to the point of condensing back into mass. Obviously there is a big gap between photons and hydrogen, but physics has spent the last fifty years proposing and analysing a zoo of subatomic activity, from quarks and neutrinos to strings. Where do the strings representing light start to bind into those representing mass? E=mc2.
The 2.7k level of CMBR would amount to a dew point/phase transition and black holes would be the eye of the storm.
If the expansion of space is a vital property and not the residue of a singularity, then the closer measurements would be the more accurate, so the question of dark energy would be moot. This curvature is the cosmological constant that balances the force of gravity.
I'll let it go at this for the moment. (Got to pick up my daughter.)

It was because of Edwin Hubble's redshift findings that Lemaitre proposed his Big Bang theory, as it was later coined by Hoyle. Not the otherway around.

I don't think Lemaitre or others thought this way, but I would be curious if any evidence supports this idea.

I suspect otherwise, but I am, admittedly, pretty low on the totem pole.

Yes, per E=mc^2; photons have relativistic mass.

I don't think light contributes much to curvature.

My limited view has light appearing to us to redshift because we have gained in relative velocity with respect to the photon emitter due to expansion. This is a pure Doppler approach. The photon remains intact, similar to the fact galaxies and clusters are barely affected.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

This is Questions and Answers. You should pick another section to promote your theory, probably Against the Mainstream.

Please, start a new topic in the right place.

Starting out your advocacy by asking a question -- especially when done to gauge where the audience is, not to actually get a question answered -- leads to topics that don't fit well anywhere.

Thanks

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It still does. That's the fundamental statement of the Big Bang model, yesterday, today, and always: the universe is expanding. How you choose to further describe that expansion in words depends entirely on your coordinate system (which in turn is a choice of picture, not a statement of reality).
Who said a meter is a measure of space? A meter is a measure of distance. Distances are increasing, that's what one means by saying the universe is expanding, and that's all one means. If the meter were to expand as well, then distances would not increase and the universe would not be expanding. You need to review the definitions of measurables used in physics before you can lay claim to any improvements.
No, that is why your incorrect interpretation of space expanding doesn't make sense.
OK, redshifts are not caused by curvature in space, they are caused by curvature in spacetime. Curvature in space depends on the coordinate system. It is becoming more and more customary to use a flat space to do cosmology, such that all the curvature, and all the redshift, comes from the time dimension.
It seems to me you are crossing the line from legitimate ATM into simple nonsense here, and continues in that vein.

[quote=George;870118]It was because of Edwin Hubble's redshift findings that Lemaitre proposed his Big Bang theory, as it was later coined by Hoyle. Not the otherway around.

I don't think Lemaitre or others thought this way, but I would be curious if any evidence supports this idea.[quote]

I mashed a lot there, sorry it doesn't come out clear.

Then the speed of light is relative to a different dimension.

Comment in this week's New Scientist, on gravity, pointing out that below the temperature for super conducting, photons gain mass and electrons start binding. Interesting for my hypothosis that light radiation dropping below the level of CMBR might start condensing into mass.

If it was accepted, then I wouldn't be proposing it.

The problem with using the Doppler effect to describe this is that it doesn't imply expanding space, only increasing distance in fixed space. The train might be moving away, but the railroad tracks are not stretching. The speed of light amounts to the railroad tracks.
Why is it so easy to accept positively curved space, but negatively curved space is taboo?

This is Questions and Answers. You should pick another section to promote your theory, probably Against the Mainstream.

Please, start a new topic in the right place.

To be fair, he did start it in ATM but Nereid moved it to Q&A (see post 3.)

so if space itself is expanding, and the meter is a measure of space, then it is expanding, so the speed of light should stay relative to this dimension, even though it is expanding.

The metre's definition is based on the speed of light so regardless of what happens with space, c is fixed.

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It must be fun to lead a life completely unburdened by reality. --- JayUtah

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Apollo: The History and the Hoax
Enter the World of Athran

Sorry for the confusion. I'm a little gunshy. I've been avoiding this topic for some time, but find myself drawn into it discussing other things.

If it doesn't get switched back, I guess I've have to put something together.

[quote=Ken G;870176]It still does. That's the fundamental statement of the Big Bang model, yesterday, today, and always: the universe is expanding. How you choose to further describe that expansion in words depends entirely on your coordinate system (which in turn is a choice of picture, not a statement of reality).[quote]

The speed of light is a rather fundamental parameter of reality. It's not just some abstraction.

The reason why it's described as expanding space and not an expansion in space is because all the other galaxies are redshifted directly away from us, with no hint of motion in other directions, as if it were an expansion from another point, so the impression was that we were the center. The concept that space itself was expanding presumably meant that every point was the center. That's why the fact that our most basic measure of space, C, isn't growing is a problem.

I'm not saying space is expanding. I'm saying that in the areas of space where gravity doesn't prevail, radiation causes it to be negatively expand.

Obviously. We call it curved because nothing travels in a flat line, or at a completely constant rate.

So saying that light causes space(time) to be negatively curved is more nonsensical then saying the universe began at a point, expanded to many times its visible size in a fraction of a moment, slowed immediately(what was the breaking mechanism for the momentum of Inflation), is speeding up again and is 96% invisible, is perfectly sensible? How about the virgin birth? I've got some stock in a bridge up in New York, cheap! Don't get these guys to do your taxes.

So saying that light causes space(time) to be negatively curved is more nonsensical then saying the universe began at a point, expanded to many times its visible size in a fraction of a moment, slowed immediately(what was the breaking mechanism for the momentum of Inflation), is speeding up again and is 96% invisible, is perfectly sensible? How about the virgin birth? I've got some stock in a bridge up in New York, cheap! Don't get these guys to do your taxes.

It would, if that was actually the current MS version of the BB, which it isn't. Perhaps you better do step one, go learn the current MS theory of the big bang (more like a big whoomph) and then come back and try again.

__________________
Howling from the Shadows

It must be fun to lead a life completely unburdened by reality. --- JayUtah

You can't reason an irrational person out of an irrational belief. --- Noclevername

Apollo: The History and the Hoax
Enter the World of Athran

Usually I list it in miles because of that, but the site I googled it off of this time had it in meters and I was in a hurry. The point still stands, though.

Maybe it will get switched back.