Right, but the fact that it behaves as matter means it must be treated integral to GR, which is the basis to BBT. What ever flavor it turns out to be isn't detrimental to the view that it influences spacetime. At least that's how I see it. We both agree that science isn't about proofs, and DM lacks multiple lines of evidence, so maybe something else is at play here. But I would put it above conjecture.I agree that observations make it look like there is more matter than we can account for. But, we don't even know for sure that it is actually matter. Or, if it is, that it is only one form of matter.
The current S&T edition has a short article on FRB (Fast Radio Bursts). This is a new area of observations that helps determine the amount of matter in space around galaxies because there is a time delay as radio waves of different wavelengths propagate at different speeds based on amount of matter that it passes through. The preliminary results are that galaxy halos are lighter than expected of normal matter. This, IMO, implies more DM. A lot more FRB observations are likely in the near future, no doubt.
Agreed, except conjecture is just a step away from subjective-based supposition. I think it merits a normal "hypothesis" level given how well it does fit the model, namely how it produces measurable tests. We seem to agree in kind, but not degree.But, that doesn't stop people from assuming that it has had effects on the evolution of the universe that make BBT fit the other data we can get from observations. That is where "conjecture" comes in, rather than some actual equation of state for dark matter that can be included directly in physical calculations about how it behaves when compressed, exposed to magnetic fields or electric fields, how it loses and gains energy (dark photons, anyone?), etc.
But those who made those estimates knew they were working with very limited information. Initial conditions for the Bang will likely never be known, so I can't imagine anyone is surprised that the estimates were wrong. This is common. Columbus underestimated the distance to India because he used Ptolemy's model, who got wrong reports of distances in the Mediterranean region.As for the CMBR, yes, it has been detected and studied, so it is real. But is it really what is left over from the Big Bang? It took some effort to get the prior theoretical predictions to fit the measurements for temperature.
I'll look at this when time allows. Thanks.And there are other issues on distribution, for example, see https://scitechdaily.com/the-universe-throws-a-curveball-the-dark-matter-distribution-paradox/ .
Well, yes, if homogeneity looks axiomatic, then you're right, I think. But observations certainly seem to support this principle. That could change but the tiny anisotropy suggests otherwise. Yet there is the "cold void" region that may introduce something more profound, so time will tell.I often wonder is there is something about the physics of the universe that is variable by location and/or time that we think is everywhere like we measure it on Earth, os that we are misperceiving reality in some way. But, that thought scares cosmologists, because it opens up so many possibilities that we are never going to be able to travel far enough from our single location in space/time to determine what it is that varies and how it does so. But, if theorists can accept that space can vary in scale, why can't they consider that time can vary in rate, and why do both have to be the same everywhere at any point we think of in times past and locations "today"? Since we have no idea how or why space "inflated", how can we be so sure it happened everywhere exactly the same way at exactly the same time?
We still don't really understand gravity, so thorough understanding isn't required even if sought diligently. Do gravitons exist? We both got engineering degrees based, in part, on Newtons "laws" because we ignored the lack of knowledge of the deeper questions, and applied the well-tested equations.