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As for Ethan’s article, IMHO dark energy is indeed “the energy inherent to space itself”. There’s an energy-pressure diagonal in the stress-energy tensor, and you can think of space expanding like a stress-ball when you open your fist. But I don’t see how the spatial energy density can remain constant. That’s creation ex-nihilo, it’s in breach of conservation of energy. I think one has to look again at the balloon analogy, which Ethan depicted. The balloon is in vacuum, the pressure within is counterbalanced by the tension in the skin, and there’s two ways to make it bigger. You can increase the pressure by blowing air into it, which is in breach of conservation of energy. Or you reduce the tension by making the skin weaker. Like it’s a bubblegum balloon. The skin gets weaker so the balloon expands, so the skin gets weaker, and so on. Replace 2D skin with 3D space, and it isn’t dark energy per se causing the increasing expansion, it’s the reducing “strength of space”. This is maybe unfamiliar to some, but it’s related to the strong force. See http://arxiv.org/abs/0912.2678 where you can read this on page 5:“We see that the modification of GR entailed by MOND does not enter here by modifying the ‘elasticity’ of spacetime (except perhaps its strength), as is done in f(R) theories and the like.”
Ethan Siegal https://medium.com/starts-with-a-bang/ask-ethan-58-what-is-dark-energy-61db04945b3d points out that “…as the Universe expands and more and more space appears between the galaxies, the energy density of dark energy doesn’t decrease,….”This must mean that not only is space constantly being created, but so is dark energy.How can this be justified in terms of conservation of energy?
The gravitational field energy is decreasing by the same amount leaving the total energy constant.
Could you say a bit more about how that works, please.
What the f* is 'energy'?
If the dark energy is magnetic energy then it is massless has no gravity but exists and can expand if it is pushed outwards to create a larger volume