I tend to think something in the nature of expansion has to exist, to accommodate the travel of light.
Still the question remains, could the universe exist without invoking the unknown properties of “Dark energy/Matter” ?
If the answer is yes, then why are we wasting/exploring models that can’t be proven ?
If the answer is NO, then how is it that we know anything ?
What other “Dark” properties will we assume and why ?
IMHO, science has transitioned from empiricism to pure speculation. It is the popular acceptance of this speculation that is destroying the foundations of belief.
With respect, I think that DE, DM, and the UDF, when taken together, are actually pretty good arguments for a designed universe.
The UDF especially. Atheists cannot invoke the Anthropic Principle on that one. (AP is their fallback position when cornered about how improbable life is.)
There is simply no way we ought to be able to see so much cool structure at billion light-year distances like this. Not by chance. And AP can't explain away that one because life can exist just fine on Earth without it.
I think so. Dr. Andrew Thomas (Hidden in Plain Sight) posits modifications to the math associated with gravity that, if shown to be accurate, would produce the same astronomical observations that "forced" the invocation of dark energy and dark matter. Not saying he's right, just that there are other possible theories that fit the observations.
-- If the answer is yes, then why are we wasting/exploring models that can't be proven ? --
All of that "wasted" effort is undertaken on account of observations, and a desire to understand the forces that create them.
-- IMHO, science has transitioned from empiricism to pure speculation. --
Yeah, there is lots of that. Multiverse, string theory, etc. It is amazing that at the "rock bottom" level, science can't get a handle on reality. I've mentioned to my kids the fact that the closer physicists look at "stuff," the more it disappears. Atoms are mostly space - what we perceive as solid material is the result of the Pauli Exclusion Principle (no more than two electrons in a given energy level).
All of this, is based on the absolute unequivocal speed of light having remained unchanged since the Big Bang.
But there has been a gnawing supposition in all of this that asks what if the speed of light traveled at different speeds over time?
Cosmological Constant
Einstein's Greatest Blunder
Einstein's Greatest Blunder
However, there is a basic flaw in this Einstein static model: it is unstable - like a pencil balanced on its point. For imagine that the Universe grew slightly: say by 1 part per million in size. Then the vacuum energy density stays the same, but the matter energy density goes down by 3 parts per million. This gives a net negative gravitational acceleration, which makes the Universe grow even more! If instead the Universe shrank slightly, one gets a net positive gravitational acceleration, which makes it shrink more! Any small deviation gets magnified, and the model is fundamentally flawed.
In addition to this flaw of instability, the static model's premise of a static Universe was shown by Hubble to be incorrect. This led Einstein to refer to the cosmological constant as his greatest blunder, and to drop it from his equations. But it still exists as a possibility -- a coefficient that should be determined from observations or fundamental theory.