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The Cosmological Constant

Posted: Thu Mar 27, 2014 3:20 pm
by ant
Does the CC have any effect on time?

What's the current speculation?

Re: The Cosmological Constant

Posted: Fri Mar 28, 2014 3:25 pm
by johnson1010
http://en.wikipedia.org/wiki/Cosmological_constant

Hm...

I don't recall ever seeing a lecture on this particular aspect of the cosmological constant, but lets see if we can puzzle out what the effects would be.

First, the cosmological constant is the proposed energy of empty space which is thought to be responsible for the acceleration of the expansion of space. The expansion of space is the cause of red-shift, or the doppler effect of light as distant galaxies are receding the "pitch" of light emitted from those galaxies shifts just as the pitch of a train engine's sound changes when it recedes from us, the stationary observer.

Time is the change in relationship of objects in space as entropy continues to increase in the universe.

Objects interact with eachother at luminal, or sub-luminal speeds. Meaning, for one electron to effect another electron it has to exchange a photon which travels at the speed of light. This is how things interact, and how the relationship of objects changes.

The cosmological constant is responsible for the expansion of space, but the effect is small and cumulative. So, while there is a large red shift for very very distant galaxies, there is a much smaller red shift for nearby galaxies, and stars within our own galaxy.

For the stretching of space to have an impact on time it would need to have an appreciable effect even on the interaction between atoms which is a very small distance.

The rate of expansion now is i think .025 meters per second over a distance of one light year. That number may be wrong, but it's pretty close from what i remember. Basically, it takes quite a lot of space to equate to measureable expansion of space on macroscopic scales.

Take into consideration also that you have to be traveling at speeds near C to achieve time dialation then i think the cosmic constant shouldn't have much impact locally on time. Of course where it really does have a big impact is in extremely long distances, such as those we observe between ourselves and very very distant galaxies where we are actually in effect looking backward in time, as the expansion of space has cause light to have to travel very far indeed to reach us, the light coming to us from such distant reachese of space is in fact pictures of the very early universe.

So i would say that it looks to me like the CC has effect "globally" not locally.

But then, the CC is the energy of space itself, which permeates everything we know of, and so whatever effect it does have locally should be a part of what we regularly experience as the "Normal" flow of time. As energy, and being equivalent to matter, it would have an effect on the path of light traveling through space and have it's own gravity.

As i say, these are my speculations, and i would have to yield the floor to anybody who has had more education in this area.

Re: The Cosmological Constant

Posted: Fri Mar 28, 2014 3:40 pm
by ant
Great response.

But then, the CC is the energy of space itself, which permeates everything we know of, and so whatever effect it does have locally should be a part of what we regularly experience as the "Normal" flow of time. As energy, and being equivalent to matter, it would have an effect on the path of light traveling through space and have it's own gravity.
Wait a second..,

Dark energy is the force of the CC.
The expansion of space and space itself create a relationship. One characteristic of that "relationship" is time.

What might be the rate of time at the moment energy and space expand into whatever it is space/energy expand into?

:?

Re: The Cosmological Constant

Posted: Fri Mar 28, 2014 4:32 pm
by Interbane
What might be the rate of time at the moment energy and space expand into whatever it is space/energy expand into?
That entirely depends on the reference frame. In relativity, the question can only be answered relative to something else. An external observer wouldn't make sense, since we cannot know how math applies to anything external to the universe(if there is such a thing). Within the expansion zone, rates of time's passing would vary throughout.

Re: The Cosmological Constant

Posted: Fri Mar 28, 2014 5:02 pm
by johnson1010
Dark energy is the force of the CC.
Yes. But dark energy might as well be just a mathematical symbol. Instead of writing the words "dark energy" which sounds like we might know what the stuff is, we might write "X", which i think is just as informative.

All we know is that there is some force which is propelling the expansion of the universe which we have called dark energy. Energy because it is acting on something, dark because it is still a mystery.

The cosmological constant implies it is space itself which has this excess energy. (This is me remembering from one of Lawrence Krauss' recent books, so i might be wrong on this).
The expansion of space and space itself create a relationship. One characteristic of that "relationship" is time.
hm.

If there were nothing in space. No radiation, no particles, how could we tell it were expanding? If there were some kind of, for lack of better word, granularity to space we could tell the difference. Those grains, or maybe instead picture a 3-d network of chicken wires forming a cubic grid.. those grid lines would either expand uniformly, in which case we couldn't see a change except from outside, or new grid lines would appear as MORE space was added, rather than the current space expanding.

I say we couldn't tell in empty space if it was expanding because there would be no applicable ruler.

I guess i am saying as i see it, it depends on the nature of space whether or not space's expansion can be clocked as time.

In empty space with no matter or energy deviations to warp any part of the "framework" of space then any expansion would look no different in proportion than if it were shrinking or staying still. You would need an irregularity, like the spacetime divet caused by massive objects to show you an increasing change in angle to the other "grid lines", or you would need the addition of "units" of space.

Not that any of those ideas are what's really out there. I am not asserting that space has a granularity, or that there IS some equivalent to a wireframe throughout the cosmos. I'm just trying to work out how there could be relationships to change and create a directionality which we could call time in empty space.
What might be the rate of time at the moment energy and space expand into whatever it is space/energy expand into?
I don't know what you are asking for here.