swansont

Those statements are descriptions of their respective models. In Newtonian terms, gravity is a fundamental force. In GR, it's the curvature of spacetime. Such statements should be understood in the context of physics. They are not meant to be taken out of context. One has to be willing to invest in some study of the subject matter to provide that context. If not, too bad. You get what you paid for.

subquantum? It's all ball bearings these days. The question is: Prestone or Quaker State?

How do they not move at the same speed relative to each other? If they are moving relative to each other, at all, they are not in the same frame.

! Moderator Note If you are going to propose such a thing you need to make it rigorous - not just hand-waving. A model. Evidence. Falsifiability. Moved to speculations.

Sound is not a gravitational interaction, so it can't have antigravity properties. No. Endy0816 showed acoustic levitation. We also have mechanical levitation (i.e. standing up, using stairs or an elevator, etc.) We can use air, too - planes and helicopters. It always involves a non-gravitational force that equals or exceeds the gravitational one. From there, application of Newton's second law of motion.

No, that's way off base. I never said we shouldn't believe what physicists say. I never came close to it. I'm saying that there is no basis to say that these discoveries show the underlying reality of the world. (Are you familiar with Plato's allegory of the cave?). Physics tells us how nature behaves, not how it is. Many of the parts of physics are calculational tools that let us more easily describe this behavior. quarks, bosons, etc. aren't "unobservable reality" We observe them, just not with the naked eye. And we are describing behavior. How they interact, and the rules of interaction . The interactions in QCD, for example - do you really think the physicists are claiming quarks and gluons are actually blue, green and red? That's reality? Can you explain how color has a meaning at that scale? Or perhaps, as I'm claiming, it's a convenience, used because of the details of the interaction, i.e. the behavior. We make models that make some kind of sense to us, and use them if they work.

...and...? I mean, so what? Are you saying That one day can't possibly be much warmer than the next, such that the max for one day is reached at 9AM the next day? The days of 24-25 August were quite cool compared to the rest of the month, but the 25th was warmer than the 24th. You found only two examples of this in a six week span. I don't see what the mystery is.

AFAIK the spontaneous transition is probabilistic. More population in the excited state leads to more transitions because the rate is proportional to the number of electrons. Plus you have stimulated emission, which is how semiconductor (and all) lasers work. Your incoming photons will induce some excited state electrons to transition to the lower state, which will vary with both the population and the light intensity. No, since it will not be a blackbody spectrum.

Synchrotron radiation is emitted because you are accelerating a charged particle. There’s no QM involved in solving for the dynamics of the particle (you could try, and discover the energy states are so close together that they could not be resolved). The basic rule is if Planck’s constant doesn’t show up, it’s not QM. Here it’s the acceleration being v^2/r, and equating that with the acceleration from the Lorentz force, qv X B

All one can validly infer from this is that the max did not occur at 9AM or 3PM

It can't be at 0K Ideal is one thing but violating physical law is another.

One other aspect of the problems with thinking physics is telling us what reality is is that over its history we've found better and better descriptions of how nature behaves. So it's ludicrous to think that Newtonian physics described reality, when we know that it was supplanted by relativity and quantum mechanics, and we know that these models are incomplete, and it's likely we will have a better model at some point down the line.

Something with a certain behavior which we call the top quark was discovered. Generally, discussions about this do not split hairs about whether or not we are searching for reality, though there are some good discussions on the bad habit of reifying these things in physics. Mermin's "What's Bad About This Habit?" is a prominent one. Later on he quotes Bohr

This is different from One is asking about science, and the other is asking about scientists. Scientists are free to do things other than science, in this case metaphysics or some other philosophy, and some of them do. I am in no position to say they should or shouldn't. But people looking at the fundamental nature of the world are doing metaphysics, whether they explicitly admit it or not. (similar to the fact that some of what I do is engineering, even though I am a scientist. Disciplines blend together in many ways)

No, of course not. How do you get from what we said to this?

I have already mentioned reflection, recombination and creation of phonons.

I had thought that the difference between religious belief (belief despite there being no evidence) and other kinds (belief because of evidence) was apparent. The equivocation is why some people try to avoid using the word. The belief referenced in your quote is not religious belief, but the use with regard to creationism is. I apologize for overestimating the situation.

Believing a theory is not the normal description; in this case its because you have a non-scientific alternative that relies solely on belief. Notice that your quote does not actually cite belief. The theory works whether you believe in it or not, and it's a good theory because it works - it matches observation and because of its strong explanatory and predictive powers. If there was a competing theory one could objectively compare them. Lamarckism, for example, was discarded because it lacks a mechanism for it to work. Not working = bad Nothing about that lays claim to revealing realty. But the models and mechanisms of evolution aren't the examples that are most relevant. I argue that would be physics, and the reason that we know physics isn't trying to describe reality is because physics itself admits that it's making stuff up to make good models. Nobody claims that electric field lines physically exist. Phonons are quantized vibrational modes of a structure - not physical particles that exist independent of that structure. Electron holes are the absence of electrons, not some particle that exists on its own. These things aren't real, physical entities. They are calculational and conceptual aids to modeling behavior.

To expand on what I said earlier: some of these explanations are leaning a bit too hard on classical physics in quantum situations. What they are doing is trying to use a classical analogue, that a body in a circular orbit has a KE that is half the magnitude of the PE, so for an orbit close to the nucleus (i.e. using the Bohr theory, which we know isn't correct) an electron in hydrogen, which has an ionization energy of 13.6 eV, has a KE of 13.6 eV and a potential energy of -27.2 eV. Those numbers aren't actually true in the QM solution, but those are the most probable values. The improper extrapolation is to assign 1/2 mv^2 to the KE, since you can't assign a velocity to the electron. When you get to an atom with a large Z, some electrons have a high enough average KE that relativistic corrections are necessary. The incorrect explanation is to say you are correcting the speed, but this doesn't show up anywhere in the equations. You solve the relativistic version of the wave equation, which gives different results than the non-relativistic version (Schrödinger equation) so there is a difference in the energy eigenstates. A relativistic correction of energy, without ever invoking velocity. I recall some years ago reading a pop-sci article on this and they linked to the paper it was based on. The pop-sci article talked about the relativistic correction of the speed, and saying that the mass of the electron increased. When I read the journal paper, none of that was mentioned. It was only the energy that was corrected, as one might expect of a rigorous paper. The pop-sci article had tried to use this classical explanation to make the effect make sense, but it made for incorrect physics.

AFAIK you can get materials from essentially zero out to 4 eV. I don't know how closely you approximate a continuum, but from a purely hypothetical standpoint of an ideal case it's not IMO more outrageous than other assumptions one can make. But at some point the practicality has to kick in, since your material is infinitely thick. (edit: see e.g. https://en.wikipedia.org/wiki/Wide-bandgap_semiconductor https://en.wikipedia.org/wiki/Narrow-gap_semiconductor ) Even under the idealized case, though, the efficiency is not 100%, for reasons I've described.

You can get different bandgaps with different combinations of materials, and varying the doping/stoichiometery. GaAs. AlGaAs, AlGaxAs1-x etc. so there are potentially a quite large number of combinations But the proposal doesn't consider the possibility of e.g. a 2 eV photon being absorbed by a material with a 1 eV bandgap, or that the material has to be thick enough to absorb all the light if you want maximum efficiency

The professor is confirming the validity of general relativity. Any more is you reading something into it. How do you empirically determine the "best" explanation without invoking philosophy or other assumptions? "True" here means valid. i.e. we have confidence that the theory can be applied and give god answers. But it's still all about behavior and observation, and not about any underlying reality.

String theory has a model, but not much in the way of experimental confirmation thus far. It's physics, but not yet an actual theory in the scientific sense of the word - as beecee noted above, it's more properly termed an hypothesis.. It's a work in progress.

What's your point? I highlighted the information from your link, where they explained how they did the max and min temperature measurements and recordings. None of this, AFAICT, contradicts that. Pasting a couple of links doesn't clarify anything about your claims.

Two things. 1) I'm thinking of the case where, owing to thermal motion, that the electron needs a little more than 1.8 eV to reach the conduction band. 2) how does an electron with no KE contribute to a current? To your point about the electron thermalizing, sure - but this represents another loss mechanism you have to worry about I don't know how you would do that. Electrons dropping to a lower energy is a spontaneous reaction. The only way to prevent it is to somehow make the lower state unavailable