We have begun a discussion about what dark energy tells us about our universe at the link provided. We hope that it will end with a better understanding of the inner working of our universe.
“Recently there have been many observations that are extremely difficult to integrate into the currently accepted theoretical models.
Particularly the force called Dark Energy has eluded any attempt make it a part of the "The Standard Model of Particle Physics" one of the most successful theories ever created.
However what makes this even more troubling is that the Standard model is based on two other very successful theories, that of Einstein General Theory of Relativity and Quantum Field Theory.
Therefore if, despite continued efforts to developed a theoretical understanding of Dark Energy in terms of these theories we still cannot succeed, should we assume that, due to how interconnected these theories are we must discard them and look in a new direction.
Not necessarily because we may be able to understand its causality in terms of our current theories if instead of trying to make Dark Energy conform to them we allow its observed properties to guide us to a more complete understanding their validly”
http://www.theimagineershome.com/blog/?p=12397
As far as I know, Dark Energy is a "buzz" word for a collection of oddities found in astronomical observations. Explaining these observations in terms of a hypothetical energy which does not emit a detectable level of light is fine but some connection with currently understood physics will be needed. This connection may say a lot.
The observed phenomenon is that the expansion rate of the Universe is presently increasing. In addition the mass-energy budget appears to contain a large contribution (almost three quarters) that is not matter. However, this is just what foreseen by the Einstein - Hilbert equation of general relativity, where it is called cosmological constant. What is strange is its value, which is very small
I doubt the dark energy is real ! I have strong assumptions that what we call dark energy is just a manesftation of energy we know seen from a specific geometrical point of view: The enegy seen from a point of view behind our understanding. The concept ot of dark energy came out to us just to answer some questions of space time. There is currently no proof (100%) that this kind of energy exists. The universe is expanding and we could explain thi by just distorsions of space in certain regions in whichtheenergy is bahaving abnormaly !
Jeff, I am sorry but the Standard Model of particle physics is definitely not based on Einstein's General Theory of Relativity. The term "Dark Energy" refers to efforts to understand some oddities in cosmology on a general energetic basis. There is nothing wrong about this approach as long as we resist the temptation to give it a mystical touch, which unfortunately is done in some popular science publications. Of course, every scientist hopes that in the end we will understand what this energy is made of. But as long as we don't, the catchy term "Dark Energy" simply reflects our ignorance.
One of the fundamental tools in cosmology is the relationship between luminosity distance dL and redshift z of a cosmological source object. In recent years this relationship has been used to measure time evolution of the expansion rate of the universe. These measurements are done with objects of redshift z nearly equal to 1. These objects are a known type of supernovae whose brightness is known well (standard candles). Measured time evolution of the expansion rate does not follow from an usual matter dominated Friedman Robertson Walker cosmological model but, surprisingly, the explanation requires us to add a new component to the energy density of the (nearly flat) universe. New component is usually called Dark Energy. Therefore, we see that indications of the existence of dark energy are indirect; but what is known from the luminosity-redshift plots (of standard candles of z nearly 1) is that the universe is presently undergoing a phase of acceleration indeed. See:
1) Perlmutter, S. (2003) Supernovae, Dark Energy and the Accelerating Universe, Physics Today, vol. 56,no. 4.
2) Krauss, L.M., Turner, M.S. (2004) A Cosmic Conundrum, Scientific American,
3) Riess, A.G., Turner, M.S. (2008) The Expanding Universe: From Slowdown to Speedup, Scientific American,
4) Appell, D. (2008) Dark Forces at Work, Scientific American,
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