swansont

Please explain this. Why is this not zero? There is no Casimir force in free space

Is it? On what basis do you make this premise? How does nothing have a temperature?

! Moderator Note You keep claiming this but I have yet to see you actually derive the expressions from classical physics. Janus has shown you to be incorrect. These two are strongly coupled. It's something you need to address, rigorously.

Sound is a wave, so the answer is yes. We can model this; it behaves as light does in this regard. http://amrita.olabs.edu.in/?sub=1&brch=1&sim=1&cnt=1

Space isn't a substance. The "state" of space is the result of (as Strange has noted) the presence of mass-energy. You seem to be proposing that space has curvature all on its own, which requires a new model.

Classical E&M says EM radiation is a wave. QM says it's a photon. Both are successful and widely used. Similarly for sound. Are phonons real? Is vibration actually a particle?

It's probably related to this device https://en.wikipedia.org/wiki/Kelvin_water_dropper You would attach an LED across the spark gap.

Coulomb's law works. The weak and strong force have their own interaction characteristics. So far as we have been able to tell, charge is charge, and independent of other properties. And physics is a subset of science. Just because you are talking about science doesn't mean you are talking about physics. And "is a donkey real" is arguably philosophy, rather than science. We've had discussions where people insist that particles don't exist and what we're seeing is field excitations. Because that's the model that they are using. Using a model that employs a particular phenomenon may lend itself to assuming that the model represents something real. When you look at electromagnetic interactions in QM, it's photon exchange.

Yes. Not sure what you mean by "different" here. What we can do is describe how things behave. Two charged particles repel orvattract in a predictable way. Much of the physics that falls under this are things we can't see with our naked eyes. But "is a donkey real" really isn't discussing physics.

In a rough sense, this is what science is trying to do. Come up with a set of consistent rules that nature follows. And if it works (which you establish by testing, i.e. experiment), well, that's what we're trying to achieve. We can explain and predict how nature behaves.

No, it's not. Even if it were true, such a statement would be unenlightening, anyway, since now you have to explain what energy is. Energy is a term that a lot of people have a misconception about, so it's not a valid starting point for a discussion. It's probably why physics usually starts talking about velocity and acceleration first, and then forces, before getting into work and energy. People do have an understanding of what position is, and direction, and so you can talk about straight-line motion, and so forth. You need to have a solid foundation in order to discuss more advanced concepts.

And my answer is no they don't, and it is a model. But nature behaves as if they were real. The real thing is the interaction. Bingo. So you know an interaction is taking place, but that doesn't actually tell you that the field is real. How would you test it to see if it physically exists?

If the reporting was proper, they would say gain or lose, since there would be no way of knowing. It could run fast, or slow. Such is the nature of having noise in your measurement. It's a little lazy to say it would lose a second — that just means that the noise is such that you would expect a difference of no more than one second against the "true" time. It's also a bit of showmanship, because the device (optical lattice "clock") only runs for a few days at best (maybe they've gotten it up to a week or two by now). Which raises the question of how many seconds you gain or lose when your device is turned off. They are awesome when they are running, but a better analogy is that they are a really, really, good stopwatch.

We now get to the point that we always seem to get to when this comes up: which sense of "real" are you applying? Because it gets very muddled if one jumps back and forth between them. 1) Real, as in not an illusion? or 2) Real, as in it physically exists, i.e. is not a model or abstraction. They Feynman quote is using #2, and in that sense electric fields aren't. Even though nature behaves in a way that they seem to actually exist. I'm not sure color fits into this, since it's not really physics; it's a perception and at best, a property of something (and not necessarily an inherent quality), so that may not be a proper analogy. And I have no desire to follow anyone down that particular rabbit hole.

Think about classical systems. Are electric fields real?