Direct detection of dark energy: the XENON1T excess and future prospects
arxiv.org
arxiv.org
https://www.youtube.com/watch?v=UzVXNFkI60Q
I also recommend his other videos if you enjoy space science.
Xenon experiments have been undergoing a bit of a crisis of faith as of late. Each iteration is a cycle of of "we predict dark matter in this energy window" -> find nothing out of place -> "well we can't rule out the long tail" -> build a bigger, more sensitive xenon detector.
Grossly oversimplified and it's been a hot minute since undergrad. But the gist is WIMPs are excluded from more and more regimes and they are running out of places to look.
We observe two apparently incongruous facts:
1) Something that we don't understand is operating on very long lengthscales (all of the effects accorded to dark matter and dark energy), which normally would suggest some very light particle to mediate that interaction
2) We don't see any new light particles (see inverse-square law tests of gravity, for example).
Chameleons offer a strategy for simultaneously explaining both. They're far from the only option in town. Intuitively, I don't really like them, but objectively, I can't see a reason to exclude them. Self-interacting theories are general (even electromagnetism is very-weakly self-interacting); a chameleon advocate could reasonably go so far as to suggest that such things are the natural order of things...
I harbor some slightly more radical opinions in that I think the whole dark energy hypothesis is broken, hell I'm not even fully convinced that the universe is accelerating in its expansion globally, and therefore the big lambda term may be way off (there are many potential other explanations for the supernovae curves out there). But I'm an engineer not a pro physicist, so my headcannon isn't worth much :).
I mean, Darwin had to see the weird finches before he saw a need for a new theory to explain them. Newton had to get hit by the apocryphal apple. Plank et. al. needed to be bothered by all those funny lines in spectra.
Fitting theory to observation is how science is *supposed* to work, 99% of the time. The reason we get fooled into thinking otherwise is that we tend to celebrate ab initio theories as the work of genius (really relativity specifically). But normal science is about finding something that doesn't make sense and making sense of it.
Of course, after that, when you have a promising theory, you then start trying to make other predictions to show your theory isn't just an overfit model. And clearly that hasn't happened yet here, so we should apply a little salt.
But I see nothing wrong with the process here at all.
This seems very interesting but I do not understand it. This seems to be saying that dark energy is produced by the sun, and.. exists alongside baryonic matter? What is “new light degree of freedom”?
Have a look at the CAST experiment for one of the standard examples of searches for such particles.
For the layperson (and perhaps everyone), "new light degree of freedom" = new low-mass particle.
Based on movies of active sunspots, I can imagine those giant twisting magnetic fields on the sun's surface possibly being a source of unusual type of energy -- possibly emitting an unusual type of matter or photon.