lamont
Contributor
MikeFerrara:
Direct observations match theory extraordinarily well for the post-3000K era, down to the scale of the anisotropy in the 2.7K CMBR being correct to produce the observed clumping of matter and galaxies in the Universe. It is when you go significantly before that, above 1GeV of energy and before 10-^-6 seconds when we no longer have a really good equation of state for the quark-gluon plasma, and above that we would like to produce the CMBR anisotropy due to inflating quantum fluctuations from a symmetry-breaking release of energy.
We know the post-3000K era about as well as you can observe anything. We can extrapolate back to the ~1 GeV area because we know physics below those energies extremely well. It is at higher temperatures and earlier times that we have issues because the early photons in the unviverse destroyed all directly observable traces of the expansion then, and we don't yet understand physics at those higher energies.
Dark matter is more of a problem of the observed gravitational density vs. luminosity of galaxies and superclusters. We can model galaxies based on their luminosity and make assumptions about the mass-to-luminosity ratio which are reasonable based on what we observe from stars and gas clouds, etc. But that causes the galaxies to fly apart, so there has to be more material in the galaxies, hence dark matter. And we've already found dark matter recently. While I was an undergraduate the major discoveries going on in physics were pinning down the neutrino mass and finding neutrino flavor mixing. We now know that neutrinos have mass and know roughly what that mass is going to be and have found a small chunk of the missing dark matter in the universe.
There is another problem with dark matter in big bang neucleosynthesis and in producing enough anisotropy of matter in the early universe to collapse and produce galaxies and other structure -- but the matter predicted to be missing from the study of missing dark matter in galactic rotation curves agrees with the amount needed to cause the formation of galaxies in the early universe. Given the agreement across such widely differing observations it strongly points to dark matter existing (just like the neutrinos existed back when energy non-conservation in atomic decay pointed at its existance but they had never been directly observed).
Heh, yeah, you don't know what you're talking about. Scientists do have to make it work. If the observed CMBR anisotropies hadn't come out to be at the scale where they were that would have been a huge problem in the Big Bang theory. If the dark matter missing from galactic rotation curves would have disagreed with the dark matter needed to have the CMBR ansiotropies cause galaxy formation due to the jeans instability that would have been highly embarassing. It all has to hang together and work. It can all fall apart, just like the theories of the Ether fell apart over a century ago...
The problem that really annoys me about arguments made by people like you is that scientifically untrained people who don't understand our current body of knowledge and where it came from and have no appreciation of the history of it are really bad at understand what it all means. When you look at the current issues with dark matter, supersymmetry and inflationary cosmology its better to put that in historical context with things like the prediction of the existance of the positron, or the "blind faith" in the conservation of energy which led to the discovery of the neutrino -- without placing the current cutting edge of scientific research within the same kind of historical context as the cutting edge of scientific research of years ago you can't draw useful conclusions from the lack of knowledge or the quality of the lack of knowledge that we have.
And I do think that historically you need to look at both the successes such as the neutrino and the positron and the failures like the ether. In the former cases there was theoretical and experimental evidence strongly pointing to the existance of those particles which was compelling and they were later found. In the latter case the ether was developed by analogy from earlier theories of wave mechanics, had no experimental evidence, had dubious theoretical foundation, and after awhile evidence racked up against it and it had to be discarded. In the case of dark matter we have an issue which is much closer to neutrinos or positrons and much less like the Ether. In the case of string theory you're looking at something that appears a whole lot more like the Ether. The failure of the Ether as a theory didn't doom all of physics, though, and didn't require the existance of God, and didn't imply that scientists were incapable of discovering anything about the Universe, and certainly didn't set themselves apart from Engineers as not having to deal with the real world or make their theories fit observable fact. The failure of the Ether instead shows how physics can pull itself out of a dead end, without having to throw away the entire program.
LOL all you want, but I'm one of those people who don't find ignorance of science and ignorance of scientific history all that amusing -- I don't particularly understand that joke...
