Markus Hanke

Because it’s a local excitation of a quantum field, like all other elementary particles too. Also, the Higgs is electrically neutral, short lived, and couples to particles that allow for rest mass - thus, even if it was “big enough”, you still wouldn’t see it visually, as it does not absorb or emit photons.

I feel the same way (which is why I don’t post here so often anymore) - too many threads that have nothing to do with science.

You’re right, it’s not the same. But then, there’s also the issue of predictability - as @sethoflagos pointed out, even in some systems the dynamics of which are fully deterministic, and even if those dynamics are computable, there may still be a limit to how far into the future you can meaningfully predict the state of that system. This is true even if all the initial conditions were known to infinite precision (which in reality isn’t possible of course).

“There are thoughts, therefore there is thinking” The issue that is often forgotten here is computability - a system may be described by a known system of equations, and may indeed be fully deterministic, and yet it may be too computationally expensive to find solutions for all real-world circumstances. A good example are the Einstein equations of GR - they are only solvable in closed form for some highly idealised situations, and numerical methods for more realistic situations very quickly become extremely resource-heavy. And the full classification of all possible solutions is still an unsolved problem.

Ok, but…my understanding is that WIMPs are thought to be a new type of elementary particle, so it’s no constituted of quarks that could interact with the quarks in the nucleus. But I think we’re getting a bit ahead of ourselves here - there is still a non-negligible chance that the observed event is just a rare type of otherwise bog-standard ordinary physics; it could even just be a statistical fluke in the data. Remember, confidence sits at just around 3 sigma, not enough to be sure. So I think more data is needed to draw more definite conclusions.

My understanding was that this means specifically that DM does not absorb or emit EM radiation, so that it can’t be detected in the EM spectrum. That wouldn’t preclude it having a magnetic moment. But maybe I’m wrong? Anyone? How would that work?

I readily admit that the technical details of the actual paper are way above my pay grade. However, from what I understand, they studied two different interaction mechanisms; the more probable one is based on the notion that both the particular type of WIMP in question and the atomic nucleus have a magnetic moment. When they come close enough, these interact, leading to transfer of momentum; since the WIMP is much heavier, it is then the nucleus that experiences a recoil. To make this work, the WIMP would need to be electrically neutral and have a mass on the order of ~1 TeV. That’s a whole order of magnitude above anything the Standard Model offers right now. Note that this data is also compatible with some proposed SUSY particles, particularly some versions of the Higgsino.

It appears we might have the first genuine detection candidate for a DM particle in one of our liquid xenon detectors: Berkeley Lab News CenterLZ Sees Surprising Result in Search for Dark MatterOf course, a single detection event - if it is confirmed to be real - does not yet constitute a discovery, but it is interesting.

Apologies, I’m only now realising that I never explicitly named the principle in question - it is indeed the principle of least action, so S represents the action. In that case my suggestion doesn’t qualify, as you need to know a good few concepts in order to solve the equation for anything at all…

I’d offer up \[\delta S=0\] because the expression has the simplest form while still capturing the widest phenomenology in physics. After all, this principle underlies most things from QFT all the way up to GR; it is, in a sense, the closest thing we have to a “theory of everything”. So I’m relating “simplicity” to the form of the equation; other choices will lead to other candidates.

A recent problem with that has been the advent of AI - cranks can now produce maths that look, on the surface, genuine and bona-fide, though of course once you look closely at it, it generally falls apart rather quickly. Likewise, one can start with a desired result (eg aforementioned orbit), and get AI to generate maths from a crank idea that on the surface appears to produce said result. All in all, it has become more labour intensive to debunk woo because of this.

I actually have that same issue - wanted to change my display name, but was unable to contact admin (my message wasn’t read). Any suggestions?

I think this was badly formulated on my part, apologies. What I meant was really that, when talking about conservation laws, the energy content of the gravitational field itself must be taken into account. This energy content is unfortunately not by itself a covariant quantity. At the same time, the covariant divergence also introduces curvature-related terms (as you correctly pointed out), which, when taken in isolation, are also not covariant. The only way around this is to introduce a new quantity that accounts for both energy-momentum of sources, and the energy content of gravity itself - it is only that particular combination that can be said to be conserved. This can be done, but I don’t know if this construction is unique.

You won’t ever see one, at least not within the domain of Newtonian and SR physics. There are fundamental reasons why this conservation must hold. In GR however, the situation is a little more subtle, as in regions of substantially curved spacetime there is no simple “law of energy conservation”. It’s possible to still formulate something along these lines, but one has to account for the self-interaction of gravity.

“Rate of time” is a meaningless concept. This is a discussion forum. If you don’t wish to debate your personal theory, then you have no valid reason for being here. While some things certainly can be expressed in terms of a single quantity like eg the gamma factor (not “rate of time”), gravity is an explicit counterexample - you need at least a rank-2 tensor field to correctly capture its dynamics. And since gravity is the dominating factor on large scales, this has a bearing on cosmology too.