swansont

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

How do you test it? How do determine if that’s the “truth”? All you have are observations. If you don’t have that, all that’s left is philosophy (points at metaphysics)

Alternate viewpoints are fine, in general; there are many instances where you can explain a phenomenon by analyzing the energy, and also by analyzing the momentum.

Your map is only valid in one frame of reference

No, I made no mention of speed. There are relativistic corrections to the energy. Synchrotrons are classical and you can talk about the speed of the electrons. No, but you don’t know the speed. The explanations talking about this are making an invalid connection, using a classical equation/concept where it’s not valid https://en.wikipedia.org/wiki/Klein–Gordon_equation#Derivation

There are relativistic corrections to the energy, which do not explicitly require having motion. The explanation that it’s relativistic speeds is pop-sci/watered-down. QM uses things like energy and momentum operators, and you solve for energy eigenstates. Which differ when the energy gets to be an appreciable fraction of the rest energy.

! Moderator Note You were the one who brought up functioning brain. Your original claim was “can you act, before you think?” This is moving the goalposts; both use of a fallacy and arguing in bad faith, both of which violate the rules

! Moderator Note Critiques of GR and exploration of an alternative model is OT - split

Science cannot answer this. It’s a metaphysical question. One can’t affirm that GR is reality, only that it models observed behavior very well. In that model, gravity isn’t a force. In the Newtonian model, it is. You’re obviously quoting someone. What is the source of this quote?

“Recorded” is not the same thing as “measured” The image caption on the right says they use a max/min thermometer. It measures the high and low over some time period. It does not mean either one occurred at 9 AM. It means that’s when the numbers were recorded. This implies for a 9 AM recording, the high is for the previous day, just as your link says (Minimum temperature is recorded against the day of observation, and the maximum temperature against the previous day) https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100141761

It’s not infinite, and the application might dictate the desired geometry.

At that energy there would be no KE left over, so the electron isn’t going anywhere, and you might need more to satisfy conservation of momentum (especially a factor for indirect bandgap materials). Some electrons would be dropping back to the ground state. Plus you will have reflection at the surface.

Just pointing out that something does not need to absorb thermal radiation, i.e. heat, in order to heat up. (an issue with our colloquial use of the terminology). A microwave oven would be a common example.

The voltage generated is proportional to the number of turns. Every loop counts toward the area that is experiencing the changing magnetic field. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html The reason for more turns depends on the application. The voltage might be the important factor. You might be using the solenoid to create a magnetic field by supplying it with current, and a longer solenoid has a more uniform field inside of it. You could be current-limited but not voltage-limited, and want a stronger field.

Its temperature can go up, since absorbing non-thermal photons will do work on it. And work can get converted to thermal energy quite easily.

There are some that don't bring anything new to it, which is a big "meh" in my book, but the Dead have a unique sound. Also in the "unique sound" category is Johnny Cash's version of "Heart of Gold"

If you learned something it's not a waste.