how much energy is ther in universe?

[zapatos]

Recession, as in cosmic expansion, is an increase in the metric of space and thus overall decrease of the density of the universe. Motion is just rearranging of things within the universe. Or to put it another way, motion is travel from point A to point B. Recession is when point A and point B get farther apart.

Is there any way to measure which is happening? For example, if I was an outside observer and noticed that two galaxies were further apart from each other today than they were yesterday, is there some way to determine if they are further apart due to expansion or motion or some combination of the two? Can you measure the decrease in density of the universe between those galaxies? If not, is it theoretically possible to measure the density?

[lemur]

Recession, as in cosmic expansion, is an increase in the metric of space and thus overall decrease of the density of the universe. Motion is just rearranging of things within the universe. Or to put it another way, motion is travel from point A to point B. Recession is when point A and point B get farther apart.

I know that people talk about universal expansion as the product of spacetime expansion being radically different from the distance between two galaxies increasing simply due to motion. My issue is with the fact that this implies that space/time exists as some actual "fabric" outside of its contents, but I am getting over that by taking gravitational field-force as the "fabric." Still, I think from the perspective of a moving object, there is no observable difference between distance growing due to expansion or motion.

 

From the perspective of the objects involved, this matters a great deal. For instance, it is impossible for any two objects to have a relative velocity of C or greater. However, objects can recede at faster than C, such that they are no longer causally connected, unless the rate of expansion slows. It creates a "horizon" for every point in the universe, beyond which no information can ever reach.

How can something cease to be a cause of something else if it caused it at some point in the past? This sounds like a statute of limitations for physical causation. Yes, they are out of reach once they exceed each other's hubble horizon but who can say if there isn't some broader field whose curvature will allow the parted gravitational fields to re-connect at some point?

 

Magically? I believe the suggestion of infinite energy was contingent on the universe itself being infinite, right? So, if the overall energy density of the universe is some finite quantity greater than zero, and the universe is infinite in size, then the total amount of energy in the universe is infinite.

Well, if the universe in fact is expanding from a beginning point "big bang," then it couldn't extend beyond the size-age it has expanded until present, right? But if there is more to the universe than what began expanding at the big bang, it could be infinite, I guess. Is there any way for it to be infinite if it all began with the big bang?

 

Surely whether the universe is infinite or finite is a pretty fundamental aspect of the model? Anyway, I don't know. I was just trying to help clear up what seemed like a misunderstanding.

I suppose you could look at it as an "aspect of the model." What other method would you have for extrapolating this aspect of the model except by applying logic to it? One problem though, imo, is that saying time actually began at the big bang, that implies that absolutely nothing existed prior to it. So if nothing was somehow suddenly replaced with everything, why shouldn't that everything be infinite? This is all very abstract, imo. To me the issues are what the relationship between forces, different forms of energy, matter, etc. were and how they would have evolved. Circumscribing the totality of "the universe" seems about as relevant to me as counting the number of words in a book and how many times each has been read.

[between3and26characterslon]

How do you know that matter-energy receding away from each other faster than the SOL won't curve around and reappear on new horizons of each other?

 

I don't, and that may happen but I don't think it's current theory. Also I'm thinking would that mean when they do appear on the horizon of each other they would be approaching faster than SOL.

 

Not "simply in another universe." I said that the interior of a black hole could generate spacetime-expansion within its contents and that this could appear as a "big bang" of an independent universe from the perspective of an observer within that universe (assuming such an observer could/would be able to observe it).

 

Ok not simply in another universe, but what I'm saying is that our laws of physics do not describe what you are saying therefore I put it to you that you need different laws of physics when describing a blackhole from the outside than when you describe it from the inside. You can not know the physics inside a blackhole if you are outside it and you can not know the physics outside a blackhole if you are inside it, therefore you can not describe a mechanism whereby a blackhole can be the beggining of a new universe. If you don't know the physics of a universe how do you know if it's a universe at all? Or capable of realizing a blackhole.

 

Why does that matter?

 

Because in the model you are describing we would be inside a blackhole which would be a tiny fraction of the mass of the universe it is in, and that universe is a blackhole which is a tiny fraction of the mass of the universe it is in and...

 

Which energy? In what context? If the universe is prone to irreversible fragmentation into regions unreachable from one another (as you said earlier), in what sense could energy be infinite?

 

If the universe is infinite. Or as in the model you describe if the universe condenses into one blackhole and space expands inside that blackhole to create another universe which in turn condenses into one blackhole in which a universe develops and condenses... you can see where this is going, then what are the consequences? Is energy shared amongst an infinite number of universes and is therefore zero in each? or does the energy of each universe add up making it infinite?

 

How can gravity and mass cancel each other? Are you just talking about variable in an equation or are you actually proposing that there is some physical mechanism where gravity and mass can cancel each other somehow?

 

No I'm talking about what Lawrence Krauss said.

 

 

How can energy be infinite in any context if it is conserved in every context?

 

 

Each expression of energy in a physical manifestation is a finite amount of energy. The only way it could be infinite is if it somehow multiplies itself under certain conditions, like if somehow unbeknowst to anyone the sun was multiplying energy and radiating it endlessly. How else could energy be infinite? You can't rely on the whole transcending the parts. If energy is conserved in every observable part of any imaginable universe, how could it be infinite on a grander level?

 

I disagree, I don't think you'd ever reach infinity by multiplying (unless multiplying by infinity or and infinite number of times)

[lemur]

I don't, and that may happen but I don't think it's current theory. Also I'm thinking would that mean when they do appear on the horizon of each other they would be approaching faster than SOL.

That is an interesting point. It makes me wonder if spacetime regions "expanding" back into each other would in fact appear as >C motion. Obviously that's not possible, but I can imagine that if space/time itself is just the internal dynamics of other force-interactions (nuclear and electromagnetic) within gravity-fields that the merging of the gravity-field-regions themselves would, if anything, result in spacetime contraction that would govern the wavelengths of the light within. Thus if EM waves were contracting faster than what we would call C in a static frame of reference, they would still be moving at C within the frame. Maybe the contraction would only be noticable in the amount of blueshifting of light between objects. Energy might intensify, thus, but there would/could be no overtaking of photons by photons behind them, in the sense that soundwaves can overtake each other when the speed of sound is broken. It's an interesting issue, though, imo.

 

 

Ok not simply in another universe, but what I'm saying is that our laws of physics do not describe what you are saying therefore I put it to you that you need different laws of physics when describing a blackhole from the outside than when you describe it from the inside. You can not know the physics inside a blackhole if you are outside it and you can not know the physics outside a blackhole if you are inside it, therefore you can not describe a mechanism whereby a blackhole can be the beggining of a new universe. If you don't know the physics of a universe how do you know if it's a universe at all? Or capable of realizing a blackhole.

Well, you're right that I'm incapable of knowing; but I CAN hypothesize on the basis of what I know, however little that may be or however flawed my application of my knowledge. Black holes seem, imo, to be gravity-wells in which EM force becomes eclipsed by gravitational force to the point that photons cannot radiate away from the matter that emits them. Since I don't think that volume can exist without electrostatic repulsion between particles, I reason that force and energy must collapse within a black hole to a dimensionless point. Then, I think it all either gets converted into gravitational field-force extending beyond the event horizon OR it must have some way to express itself within that horizon. If it expresses itself within the horizon, I think it may generate spacetime-expansion in a way that does not extend outward. The possibility of this in my thinking is aided by my belief that space/time is a function of force-field intensity differentials rather than it being a container for those fields. Thus, imo, it could be that what we perceive and measure as space/time is in fact just a ratio of nuclear and electromagnetic forces to gravitational-intensity. We could exist as part of a single dimensionless point of convergence between these three (or 4 if you count the weak force) where our perception of gravitational fields as being larger than atoms is due only to the fact that the nuclear and EM fields are relatively stronger and therefore "tighter" relative to the gravity-field "particles" which appear as containers for the "tighter" fields. I know this is sounding crackpottish just because I'm having to write so elaborately to explain it but just try to imagine an extremely dense force-field that begins to differentiate internally into variable intensities of force and how this could either be interpreted as shrinking/contraction of the "tightening" fields OR as expansion of the "loosening" outer field.

 

 

 

Because in the model you are describing we would be inside a blackhole which would be a tiny fraction of the mass of the universe it is in, and that universe is a blackhole which is a tiny fraction of the mass of the universe it is in and...

What if the total amounts of force/energy were not as important as the (changing) ratios of force-field densities? E.g. what if protons, electrons, and photons do not so much consist of fixed amounts of absolute energy as they consist of differentiated ratios of field-force and the ability to interact with each other within "looser" fields?

 

 

 

If the universe is infinite. Or as in the model you describe if the universe condenses into one blackhole and space expands inside that blackhole to create another universe which in turn condenses into one blackhole in which a universe develops and condenses... you can see where this is going, then what are the consequences? Is energy shared amongst an infinite number of universes and is therefore zero in each? or does the energy of each universe add up making it infinite?

I suppose if I go with this idea of diffentiating ratios of field-force determining the internal mechanics of any given "universe" then energy would be infinite only because it is infinitely divisible into relative multiplicities of particles.

 

 

 

No I'm talking about what Lawrence Krauss said.

I'm not familiar. Maybe you could elaborate it more here to bring the discussion more in that direction.

 

 

I disagree, I don't think you'd ever reach infinity by multiplying (unless multiplying by infinity or and infinite number of times)

You'd never reach infinity if you assumed that energy quanta were absolute but if they were a function of the ratio between gravity-strength and the strength of other forces, energy would multiply according to how much the differential between the forces grew. Think of it like the energy potential of a thermodynamic system increases as the temperature differential between the hot area and cold area increases.