Quote:
Originally Posted by Tim Thompson
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.)