I've always had a hard time swallowing the concept of dark matter- seems like a scientific stop-gap to me. Interesting stuff. https://phys.org/news/2020-01-evide...l6rSCTYk2NexzgJywCxdZZO1Xmwak5LWnPW9OIAm0qjKU
I've begun to suspect that instead of gravity being a distortion of spacetime caused by mass, spacetime is in fact an emergent property of gravity. Mass doesn't distort spacetime via gravity, rather, concentrations of gravity create mass.
Air (unlike dark matter and dark energy, apparently) has profound, obvious, testable, and observable effects on the rest of the non-air world.
The whole business of Dark Energy and Dark Matter didn't seem to make much sense to me when compared to something like MOND. After all, MOND basically says that our understanding of physics gets things wrong when we try to apply them to the scale of things like galaxies and the universe. That doesn't seem to be too outrageous. After all, it makes little sense for the rules that apply to atoms to apply equally as well as to something as large as a galaxy or a galaxy cluster. That'd be akin saying that the rules which applied to your hair apply to humanity at large. Seems silly, right? And yet, that may not be the case. When I saw Neil deGrasse-Tyson speak a few years back, someone asked why he supported things like Dark Matter and Dark Energy over MOND, his answer was one in which I have a hard time arguing with. The gist of his response was basically that the existence of Dark Matter and Dark Energy requires fewer rewrites of our understanding of physics than does something like MOND. So, it seems to me that maybe DM and DE make the most sense.
This is really interesting stuff. Firstly, people are confusing dark matter with dark energy. Despite the similar names, these are different things and not at all linked. Dark matter is the hypothetical material that would account for the structure of galaxies. Without it the galaxies we see would fly apart. We're not sure what it is - it could be fundamentally the same sort of "stuff" that we already know about or it could be something more exotic. Dark energy is another unknown substance - which certainly is more exotic - that is used to account for the accelerating expansion of the universe. It is proposed to arise from the vacuum of empty space. Of course, if the universe is not actually accelerating then there is no need to believe it exists. Now, I have heard about this new research in a couple of different places and there are differing views about it. To my knowledge it essentially suggests that previous measurements of acceleration were flawed and that what was measured was a phenomenon local to our part of the universe, presumably caused by the interactions of nearby galaxies. But there are some who have challenged the findings and cautioned that the results need to be confirmed before we start overturning existing theories.
That's essentially one of the conclusions of loop quantum gravity. Spacetime is emergent as an accounting mechanism for the relationships that exists between actual things.
I mean, yeah, that's basically how it started. There's something not adding up, so put an x in there and try to figure out what it stands for. Should've just left it alone, and kept it to spring it on him in the Red Room. The notion that gravity somehow behaves differently at galactic distances is really freaky to me . . . but I guess there's precedent. Strong and weak interactions only matter at sub-atomic level, and one of Maxwell's equations needed a term added to make it work properly. So I'm doubtful, but who knows?
We're definitely overdue some new physics so I wouldn't be surprised if something like that were the case. The problem is that - whatever theorists come up with - checking things experimentally has become more and more difficult and is becoming prohibitively expensive. The LHC confirmed the Higgs but it ruled out several versions of SUSY and some of the other things they've been working on so it is difficult to see where they can go next.
