Finally, A Reexamination of Dark Energy and Cosmic Expansion

When something sounds too audacious or too stupid to be true, it is always worthwhile to re-examine the possibilities. I have been saying for quite some time that cosmology is very ripe for re-examinations of things like an expanding universe, cosmic inflation, dark energy, and dark matter. Well, there is some light at the end of the tunnel.

This is from the Universe Today Blog (1-12025)

New Study of Supernovae Data Suggests That Dark Energy is an Illusion

Dark energy is central to our modern understanding of cosmology. In the standard model, dark energy is what drives the expansion of the Universe. In general relativity, it’s described by a cosmological constant, making dark energy part of the structure of space and time. But as we’ve gathered more observational evidence, there are a few problems with our model. For one, the rate of cosmic expansion we observe depends on the observational method we use, known as the Hubble tension problem. For another, while we assume dark energy is uniform throughout the cosmos, there are some hints suggesting that might not be true. Now a new study argues we’ve got the whole thing wrong. Dark energy, the authors argue, doesn’t exist.

Let’s start with what we know. When we look out across the billions of light-years of cosmic space, we see that matter is clumped into galaxies, and those galaxies are groups into clusters so that the Universe has clumps of matter separated by great voids. On a small scale, this means that the distribution of matter is uneven. But as we go to larger scales, say a billion light-years or so, the average distribution of matter evens out. On a large scale, the cosmos is homogeneous and not biased in a particular direction. This means we can broadly describe the Universe as the same everywhere. This is known as the principle of homogeneity. By applying this principle to cosmic expansion, we can model the Universe by the Friedmann–Lemaître–Robertson–Walker (FLRW) metric, where dark energy is a cosmological constant.

Opponents of the standard model argue that the principle can’t be applied to cosmic expansion. Some even argue that the basic principles of general relativity can’t be applied on cosmic scales. In one such model, known as the Timescape model, it’s argued that dark energy would violate the principle of equivalence. Since the principle equates inertial energy and gravitational energy, there is no way to distinguish cosmic expansion as a real effect. Furthermore, since we know that gravitational fields affect the rate of time, the Timescape model argues that the Universe can’t be homogeneous in time. Basically, the model argues that within the gravitational well of a galactic cluster, clocks would run more slowly than they would within the vast empty cosmic voids. Over the billions of years of cosmic history, this difference would build up, creating a variance of time throughout the Universe. It is this time divergence that would give the appearance of cosmic expansion.

I have no idea whether this interpretation will hold up but at least people are trying to eliminate incoherent concepts, such as dark energy and dark matter.

WTF? The Mysterious Force We Call Dark Energy Makes Up More Than Two Thirds of the Universe

The sentence in the title above came from the EarthSkyNews blog/newsletter. I expect better from sources purporting to explain scientific concepts.

“The mysterious force we call dark energy makes up more than two thirds of the universe.”
(www.earthsky.org, 11-13-2024)

First “Dark Energy” is indeed mysterious as it is entirely hypothetical, the concept being created to explain the hypothetical acceleration of the hypothetical expansion of space, or space-time if you prefer, in the universe. No one has yet found evidence to support its existence (the original issue leading to it being hypothesized does not count as evidence).

Using the label “energy” for a “force” is quite odd as these two are not the same.

Force is an external factor which can change the state of rest or state of uniform motion of an object. (Newton’s first law)

Energy is defined as the “ability to do work, which is the ability to exert a force causing displacement of an object.”

So an object able to exert a force possesses energy to do so, and so energy is the source of the ability to exert a force or forces.

Dark energy is not a force, it is an energy which is the source of the force causing the expansion of the universe to accelerate, or so it is proposed.

Moving on to “dark energy makes up more than two thirds of the universe.” This should be better stated as “dark energy, if it is real, would make up more than two thirds of the universe” or “the theory hypothesizing the existence of dark energy also claims that it would make up more than two thirds of the universe.”

Under no circumstances should a mysterious energy, lacking any proof of its existence, be referred to as if it were a fact, certainly not in the same sentence!