Need for Dark Energy
We do not understand the motion of galaxies.
Dark energy involves the observed motion of galaxies
The basis for dark energy is not justified.
In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain the observations since the 1990s indicating that the universe is expanding at an accelerating rate.
After about 40 years, since 1980, this 'most accepted hypothesis' remains 'unknown' which suggests the possibility it offers nothing to become known.
The nature of dark energy is more hypothetical than that of dark matter, and many things about it remain in the realm of speculation. Dark energy is thought to be very homogeneous and not very dense, and is not known to interact through any of the fundamental forces other than gravity. Since it is quite rarefied and un-massive — roughly 10^-27 kg/m3 — it is unlikely to be detectable in laboratory experiments. The reason dark energy can have such a profound effect on the universe, making up 68% of universal density in spite of being so dilute, is that it uniformly fills otherwise empty space.
From a National Geographic article:
Dark energy is even more mysterious, and its discovery in the 1990s was a complete shock to scientists. Previously, physicists had assumed that the attractive force of gravity would slow down the expansion of the universe over time. But when two independent teams tried to measure the rate of deceleration, they found that the expansion was actually speeding up. One scientist likened the finding to throwing a set of keys up in the air expecting them to fall back down-only to see them fly straight up toward the ceiling.
Scientists now think that the accelerated expansion of the universe is driven by a kind of repulsive force generated by quantum fluctuations in otherwise "empty" space. What's more, the force seems to be growing stronger as the universe expands. For lack of a better name, scientists call this mysterious force dark energy.
Unlike for dark matter, scientists have no plausible explanation for dark energy. According to one idea, dark energy is a fifth and previously unknown type of fundamental force called quintessence, which fills the universe like a fluid.
Presently dark energy is unexplained.
When astronomers look at images of distant space they see clusters of galaxies in a region of space.
When they look at the spectra of all those galaxies all have a red shifted hydrogen atom absorption line. In the 1930's the red shift of this line was known to be proportional to distance for many galaxies.
Some person decided henceforth this red shift should also be treated as a velocity.
As our imaging technology improves we can observe fainter objects which are faint due to distance. These more distant objects have a higher red shift. When treated as a velocity an increasing red shift implies increasing velocity at greater distances.
We can image and record the spectrum for very distant objects; the highest Z value is now 11 times the speed of light. It is safe to assume observed Z values will continue to increase and so this assumed expansion will continue to accelerate.
Since this mistake in the 30s, astronomers see all the galaxies in all the clusters are zooming away from Earth.
Quasars add to this misperception with its hydrogen emission line with an extreme red shift (that is the atom not the quasar).
Unfortunately there is no visible cause for all to be moving away from Earth, or for that observed velocity. That combination of velocity and direction is simply impossible to explain.
When I look at those galaxy clusters I am curious about relative motions within a cluster. To determine them we must image the cluster many times over hundreds of years, probably much longer, to detect any changes in positions. Over time perhaps a velocity and trajectory could be found for each. I expect these motions will be slow. For example, the Sun takes 226 million years for one orbit in the Milky Way. Much time is needed to learn about galaxy motions. Right now there is no knowledge of lateral motion of galaxies in clusters. The only known detail about a galaxy motion is its velocity away from Earth (from a red shift due to distance). There is no visible cause for this recession.
In this context cosmologists can explain nothing about galaxy clusters, neither their velocities nor their positions.
With this complete lack of understanding of the universe at the galactic scale cosmologists are confronted with no viable explanations for their observations at this scale.
With the precedent of dark matter for hiding an inability to accurately predict the complex motion of billions of stars in a galaxy, an excuse at the galactic scale was introduced: dark energy.
Dark energy is claimed to be everywhere and causing the galaxies to be where they are and why they are moving. No further details are provided.
Dark energy is the name for an excuse for having no real explanation. Cosmologists need the facade of adult comprehension, not of adolescence on the way to maturity. The honest version is we do not have enough data to truly understand the universe at the galactic scale.
This disinformation campaign also includes further false certainty like the 68% number which is quite impressive to anyone unfamiliar with the creative usage of statistics.
Dark matter suggests cosmologists are attempting to understand motions of stars. Models are being updated based on observations of spiral galaxy rotation.
Dark energy suggests cosmologists are making no attempt to learn about motions of galaxies.
Perhaps the end of this post is too cynical but what is the correct response to the precise claim of 68% of a complete unknown?
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