The expansion force in space is tiny, so tiny that within a solar system or even a galaxy it has little effect and is generally swamped by gravity. And we usually consider that gravity is a very weak force anyway. Plus, dark energy isn't even the expansion force, it is the extra bit of the expansion force we can't account for (is that correct?).
So, after all that, how does it come to make up nearly 3/4 of the universe? Or come to think of it, by what measure is it 3/4?
2012-06-29T03:26:09Z
I don't want speculation or ignorance, I just mean how have we calculated there is so much of it when it has such a tiny effect? And allied to that what is the 3/4 figure anyway - is just by total energy or what?
2012-06-29T05:41:52Z
Look guys, don't talk bobbins about if dark energy exists or not. I'm asking how come the calculated amount is so big. It makes no difference if physics is wrong or not, there is still a current calculation for it.
Lola F2012-06-29T06:16:35Z
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The calculation for it, like all the rest of the parameters of the big bang, is currently based primarily on analysis of WMAP data. See http://map.gsfc.nasa.gov for details. There are other ways to estimate it, such as measuring the acceleration of the expansion directly with supernovae, but that is much less accurate.
The 3/4 refers to the fact that the energy density of dark energy is 3/4 of the critical density required for the universe to be flat. The universe is indeed very close to flatness, the rest of the energy density coming from matter.
It would be inaccurate to call dark energy a "force" in GR, just as attractive gravity between masses is not a force in GR. Both the accelerating expansion and attractive gravity of masses are simply different kinds of curvature of spacetime.
A problem occurred with the big bang theory. To account for the discrepancy it was decided to invent an invisible and undetectable thing called dark matter & dark energy.
I'd suggest that there is some other "more plausible" explanation for the discrepancy that does not require dark energy.
We just need to wait until cosmologists re-evaluate the situation.
Something new to our media science is the concept that quantum wave particle duality may be the cause of the accelleration in universal expansion. Since all electromagnetic particles, like light, behave as a wave untill they contact something and apear as particles, the probabillity wave for that particle potentialy encompasses the entire universe where the wave is aligned, these waves are constantly interacting over vast distances. It is suggested that this property is driving the universal expantion by exerting quantum vacuum presure on all the objects in the trejectory of the wave.Since there are so many of these photonic waves ripping through the cosmos in all directions,though the effect is small on a localised level, over the expanse of the universe the cumulative effect is greater than gravity across the vastness of intergalactic spaces and is supplying a constant outward thrust to all the galaxies. So far that makes more sense than a mysterious non force force driving expansion. It could also be the result of weak interaction of the multiverses resulting from small perturbations in the dimensional seperations of these coexisting universes we inhabit. These are realy big questions with realy long and potentialy wrong answeres.Fact is we may never be able to prove any of it since we are locked in our dimentional frame and can't directly observe these co-universii.All we can do is take carefull measurments of lot's of stuff and ponder the implications of the data till something makes sense.