Dark Matter and Dark Energy

[axmukher]

The billions of stars in the sky have been throwing out huge amounts of energy for billions of years, ever since the big bang. We can see a portion of that energy as light coming directly to us. But all the rest of the energy that has spewed out is trapped within our universe but is not visible to us. We can't see this energy moving around in the huge void of space, but surely it could not have vanished in a closed system. Could this be the dark energy that astronomers refer to? And matter being equivalent to energy, this may be a manifestation of the dark matter that is proving so elusive to see. This energy should be growing every moment as the stars continue to add to it continuously. And if this happens it should accelerate the expansion of the universe. No? :roll:

 

[SteveCNC]

I can't really argue too much with you after all who knows if we are even aware of all levels of energy coming off a star . Sure we have senses that can see the light and we can feel infrared and we are able to detect many of the invisible emisions but are we aware of all possible forms of energy a large object like a star can create ? maybe not , as much as I would like to think we have things all figured out , I know that's not the case .

here's a thought along similar lines ,

If space is expanding at a rate slower than the speed of light (not sure what it's current speed is but I believe it is slower) then any energy that isn't absorbed by an object should run into the edge of the universe eventually , so what happens when it does ? would it cause a build up along the edge like a blob shaped shell around the entire universe and all this energy with no where to go ? Now either the energy goes somewhere or that shell is going to thicken up even with the expansion I doubt it can keep up with the buildup . Perhaps that's what's pushing the expansion to go faster and faster .

 

[mafrank]

I have another question. Astronomers can observe that the expansion is going faster and faster. But, if time is relative, then could it be that time for us is really just decelerating (instead of the expansion accelerating)? Perhaps we're approaching a black hole?

If our time were decelerating, then changes in the universe would appear to be accelerating, relative to us. Right?

 

[a_lost_packet_]

...This energy should be growing every moment as the stars continue to add to it continuously. And if this happens it should accelerate the expansion of the universe. No? :roll:

No.

First of all, what kind of "energy" are you maintaining these stars are emitting? Secondly, how would such energy interact with the Universe in order to "expand" it.

The expansion of the Universe is not occurring because the bodies in space are accelerating locally in velocity away from each other. In fact, some galaxies are moving towards each other, attracted by gravity. Space is "expanding" itself and the bodies that "rest" within it are moving apart relative to each other, but not locally. They aren't "accelerating" as far as they are concerned. They're just along for the ride. Gravity is locally stronger than this rate of expansion so galaxies continue to hold themselves together and interact because of it.

If such a mechanism existed, given that it was possible for a star to emit unknown energy we could not detect and have that interact with spacetime, wouldn't we witness some sort of more localized effect in clusters of stars rather than a general expansion of space itself?

 

[SteveCNC]

say a_l_p , did you read the last paragraph of my post above ? if the expansion rate is less than the speed of light then energy of any kind traveling away from it's source at the speed of light must eventually reach the edge of the expanding universe if it dosen't hit something else first . What happens when it gets there ?