Invariably when you cross-reference his postulations his articulations are meticulously fastidious.

A mathematical posit is hereby proposed whereby a graph with an algebraic formulae be incorporated acceding proportional benevolence thus eliciting future fan “likes” in his favor. ]]>

I agree it is extraordinary that space-time is appearing out of nowhere and I have no explanation for this – I just don’t see how we can ascribe the cause of it to invisible energy.

I fail to see how the SW effect can be interpreted as a direct observation of dark energy, but maybe it’s just me.

First, let me note that no one says that expansion of space-time is caused by an apparently visible* “invisible” energy. Expansion is ongoing, it is the acceleration that is of concern here. Those are entirely different things. (Say, when warming water, heat is responsible for increased temperature, increased heat flow for accelerated temperature increase.)

Essentially, without dark energy expansion would still be free-wheeling. Inflation is what once caused free-wheeling expansion to happen.

Also we are not considering appearance of initial spacetime, that is a matter of inflation before the free-wheeling expansion of space-time.

Second and more importantly, now we are asked to leap between two different theories.

That the acceleration can be interpreted as dark energy/negative pressure is built into standard cosmology. So that shouldn’t be surprising, it is what the theory says.

What is the causation here is a matter for more theory. Considering standard cosmology it could be that:

1) Dark energy is caused by an accelerated expansion. I dunno about the physics of that, but it is permitted.

2) The accelerated expansion is caused by dark energy. This is what the hypotheses of vacuum energy comes out of, and the observation that dark energy can be interpreted as a cosmological constant allows for this.

3) The acceleration/energy observation is caused by a constraint of zero energy. This is what some of the results discussed in another thread can be used for.**

4) A combination of standard cosmology parameters causes (a constraint on) DE. Again, I dunno about the physics of that, but it is permitted.

– Any other physics outside of standard cosmology than 3) – 4) causes DE.

Third and not important at all, I can’t resist leading off into more physics =D :

I don’t think it is correct to criticize a perfectly valid theory for what theories outside of it predict. That DE exists shouldn’t be a matter of argument, if one accepts standard cosmology theory. What DE is, should be questioned.

You know, this is easily turned on its head. If there is no zero point energy of fields where did it go? What causes the finetuned canceling of vacuum energy? These are the questions that arise if we find that DE isn’t tied to the vacuum but something else entirely.

Considering that, I find it encouraging that there is an available hypothesis that solves all of this. While raising other questions, naturally. Why is the cc so low? Is there any other viable theory than inflationary multiverse theory that predicts this?

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* By visible I mean “observable”, and by observable I mean “observable according to theory”.

** Personally I think the constraint is somehow a result of general relativity/the equivalence principle as per some of those results, and the cc is specifically “the cause” of dark energy.

]]>‘Dark energy’ is not energy, it has energy which is a subtle but important difference. Energy is a property of dark energy, expressed in joules, calories, BTU’s etc.. Similarly, matter is not mass. Again, mass is a measurable value, a property of matter.

Specifically, one property that Dark Energy does not have in its ‘at rest’ or inertial, non accelerating state is ‘mass’. However, in any type of acceleration mode it does have mass and, as a consequence, will exhibit matter like attributes. If this seems difficult to envisage, the photon, or any electromagnetic wave, is another example of something which if it were ever ‘at rest’ would appear to have no mass yet when it moves it has momentum.

The statement *Gravity makes an apple fall to the ground* is obviously true but it is similar to saying *Fire makes us warm*. In the case of fire, it is electromagnetic radiation that makes us warm, an energised form of dark energy. Matter, the mass of which is subject to the famous equation e=mc2, is another manifestation of dark energy and, you will need to take this on trust for a moment, but gravity is caused by a third form, as detailed in the table below.

It helped me, maybe the extract could help others?

]]>So again thanks, for providing the history details!

]]>Friedmann wrote a solution to the Einstein field equations which is similar to the dynamics of a projectile. If the energy of the projectile is too little, kinetic energy less than potential, it falls back. If it is just at the escape velocity, total energy = 0, it will in an infinite time period reach zero velocity at “infinity.” If the kinetic energy is larger than the potential the projectile escapes to “infinity” with some terminal velocity > 0. These in a cosmological setting correspond to the closed space, an open flat space and the hyperbolic saddle shaped space. Friedmann’s model was not regarded widely, in part because Friedmann died not long afterwards of tuberculosis. His model was picked up in the forthcoming decade by Robertson,Walker and Lemaitre who worked out more of the physical consequences or observable aspects of this spacetime.

At around the same time the Dutch mathematician Willem de Sitter worked the Einstein field equations in 5 dimensions and examined the curved 4 dim spacetimes that could exist as embedded spacetimes. These are the de Sitter and anti-de Sitter spacetimes. The de Sitter spacetime is a form of the Friedmann-Lemaitre-Robertson-Walker spacetime for a constant energy density assigned to the space. This constant energy is what we call dark energy and is a cosmological term intrinsic to the spacetime metric.

These developments were conducted in the early 1920s, on the heels of Schwarzschild’s solution for a static gravity field. These early developments in general relativity were eclipsed by the much bigger interest in quantum mechanics that developed in the mid to late 1920s. The next interruption came with world war II, where Oppenheimer and Snyder worked out much of the physics of black holes in 1939, and three years later Oppy was up to his behind in matters of fission, uranium gun barrels, plutonium implosion and fat-man at Los Alamos. Broad interest in general relativity only resurged about 10 years after WWII.

LC

]]>The situation has some reminiscences with the aether theories of the late 19th and early 20th centuries. A large number of degrees of freedom (or a continuum of such degrees) were assigned to a type of fluid. The solution to how electromagnetic radiation propagated in space consistent with dynamics was simply due to 6 parameters in the special relativistic boosts and rotations. We are facing a similar problem these days.

LC

]]>I agree it is extraordinary that space-time is appearing out of nowhere and I have no explanation for this – I just don’t see how we can ascribe the cause of it to invisible energy.

I fail to see how the SW effect can be interpreted as a direct observation of dark energy, but maybe it’s just me.

]]>“The main results of the FLRW model were first derived by the Soviet mathematician Alexander Friedmann in 1922 and 1924. Although his work was published in the prestigious physics journal Zeitschrift für Physik, it remained relatively unnoticed by his contemporaries. Friedmann was in direct communication with Albert Einstein, who, on behalf of Zeitschrift für Physik, acted as the scientific referee of Friedmann’s work. Eventually Einstein acknowledged the correctness of Friedmann’s calculations, but failed to appreciate the physical significance of Friedmann’s predictions.”

Friedmann had presented Einstein with the solution before Hubble’s observations, but he was so intent on modelling the static universe he missed the implications. Had he realised the consequence, he could have predicted the expansion before Hubble’s publication of his measurement of expansion, that was the blunder to which he later referred. As you say, it is ironic that it resulted in the CC which accidentally ‘predicted’ dark energy.

]]>“The main results of the FLRW model were first derived by the Soviet mathematician Alexander Friedmann in 1922 and 1924. Although his work was published in the prestigious physics journal Zeitschrift für Physik, it remained relatively unnoticed by his contemporaries. Friedmann was in direct communication with Albert Einstein, who, on behalf of Zeitschrift für Physik, acted as the scientific referee of Friedmann’s work. Eventually Einstein acknowledged the correctness of Friedmann’s calculations, but failed to appreciate the physical significance of Friedmann’s predictions.”

Friedmann had presented Einstein with the solution before Hubble’s observations, but he was so intent on modelling the static universe he missed the implications. Had he realised the consequence, he could have predicted the expansion before Hubble’s publication of his measurement of expansion, that was the blunder to which he later referred. As you say, it is ironic that it resulted in the CC which accidentally ‘predicted’ dark energy.

]]>