So the way I understand it dark matter doesn't even have any physical interaction with matter. But it must be affected by gravity, or else it wouldn't end up trapped in black holes right?
Black holes sans accretion disk clearly satisfy these criteria.
But if it turns out it's black holes, I'm guessing it would have physical interaction with other matter but still be hard to detect and not interact in the usual way we expect of normal matter.
All this is speculation though, and I don't really know what I'm talking about.
Could it be large transparent gas clouds? No, it turns out that gas clouds aren't completely transparent, and can be measured in various ways. We looked, we checked, such clouds don't contribute enough mass.
Could it be dust clouds? Dust clouds are not luminous but they do block visible light, so they'd be obvious. We looked, we checked. It wasn't dust clouds.
Could it be rogue planets or brown dwarfs? No, such objects would cause gravitational micro-lensing effects, which can be observed in dedicated campaigns. We looked, we checked. It wasn't planets or brown dwarfs.
The only theory that has withstood the last several decades of experimental observation and simulation has been the dark matter theory (weakly interacting massive particles at sub-relativistic speeds). It's the only thing that explains all the evidence across the board.
It seems most astronomy theoreticians will rather not rock the boat, they will rather keep believing in invisible stuff permeating space everywhere with variable but exactly right density so it is consistent with star motions and images observed. I guess it's because stuff with infinity of degrees of freedom is traditionally much more secure paradigm to base a career on than to question the established beliefs in applicability of Newtonian mechanics/General relativity.
> "The only theory that has withstood the last several decades of experimental observation and simulation"
Which competing theories were put to stand the test of observation? What made them not stand well in light of observations?
> "It's the only thing that explains all the evidence"
There is little example to such a thing as scientific theory explaining all the evidence. But even if dark matter paradigm did do such a feat, it would not be a good sign for the truthfulness of it. Theories that explain everything are suspicious - they may be exercises in fitting and may not be so scientific or useful as competing theories that explain less, but better.
As such there's no value in actually debating you on these points.
Please read my post again and if you can, address the points made there.
EDIT: those points, slightly expanded, are:
1) Could it be that Newtonian/Einsteinian models of motion in extremely distant, never visited places are extrapolations in error? If not, how do we know that, since we cannot experiment there, with massive objects on astronomical scales?
2) Is working in line of a popular paradigm much more preferable to most researchers than proposing a radical new theory that is inconsistent with it?
3) Searching for different model / theory is hard work but if it successfuly explains something and provides directions to continue, is preferable to fitting massive quanta of data to a model with infinity degrees of freedom (density of dark matter in space).
4) It is hard to find an example of scientific theory fitting all the evidence. Fitting all the evidence suggests we are doing a fitting exercise, not a scientific theory.
It's your job to not be wrong about knowable things. Read a summary of the literature if you are actually interested instead of just proposing that a well accepted theory is wrong because "theoreticians" are biased.
I was requesting the parent to point out which of my points and why they are wrong. I think reply of such kind would be far more useful to many people here sharing similar views to mine on the idea of dark matter or usefulness of academic work in this direction.
> 'Read a summary of the literature if you are actually interested'
I am actually interested in what people here, including you, think of my points; I was hoping for substantive replies to them. Your suggestion to 'read up and shut up' comes out as arrogant and uncalled for.
Or whoever programmed our reality couldn't build a consistent macro-physics engine so they hacked something together while hoping biological evolution wouldn't lead to anything that would notice it. Everything was going smoothly with the natural-selection add-on until the platypus and hominids showed up.
Dark matter seems to interact weekly even with itself, contrary to regular matter. So it really is completely different stuff, not just matter that's hidden from us.
There are four fundamental forces that govern the universe: gravity, electromagnetism, and strong and weak nuclear forces.
Dark matter interacts with gravity, but not electromagnetism. Electromagnetism is the force that we are acting upon when we touch things, or things bump into or collide with one another. Also, it's what makes light and magnetism.
So dark matter would never hit or bump into anything, but it can, say, orbit something.