On Monday, June 23, 2025 at 3:16:50 PM UTC-6 John Clark wrote:
On Mon, Jun 23, 2025 at 10:32 AM Alan Grayson <[email protected]> wrote: *>>> So, in this scenario, the experiment can be done so that tidal forces will not be detected* *>> Obviously it can be done! It's ridiculously easy to perform lousy experiments that have huge error bars, but such experiments can tell you nothing. More precise experiments are more difficult but they have the potential to tell you that something is not true. Extremely precise measurements have been made but none of them show that the equivalence principle is false. * *> I am not contemplating lousy measurements. If I have great measurements and detect tidal forces, therefore denying the EP, I can easily change the design of the experiment, so tidal forces will not be detected.* *Yes exactly. No matter how good your instrument is, I can ALWAYS find a volume of space that is so small your instrument is not good enough to detect tidal forces, and this fact holds true all the way down to zero volume and a 100% perfect instrument.* * >>> But this is obviously contrived, and depends on NOT having no definite idea what "local" means. AG * *>> The operational definition of "local" means that no matter how sensitive your tidal force measuring device is, I can pick a volume of space that is so small that your device cannot detect that tidal force. If your device is infinitely sensitive (such a device would be unphysical, but never mind) then "local" would be a point which has zero volume. * *> Sure, you can always design the experiment to get the result you want.* *The experiment seems pretty damn fair to me. You are allowed to use an instrument of arbitrary precision, even one that is absolutely perfect. And I am allowed to use a volume of arbitrary smallness, even one that has zero volume. * *> Is this what you call "physics"? AG* *No, that's what I call "local".* That's what I call BS! "Local" means that an event in spacetime depends entirely on the local conditions, such as field strengths at that point. It doesn't mean an experiment can be rigged to get some desired result. AG *>>>>The reason all objects fall at the same rate under the influence of gravity is because gravitational mass and inertial mass are equivalent. And that is the Equivalence Principle. * *>>> I'm not sure how this conclusion is reached. AG* *>> If you double the gravitational mass of an object falling to the Earth then you double the force it feels from gravity, but if they are equivalent then you have also doubled the inertial mass, so it takes twice as much force to produce the same acceleration. Therefore the rate of acceleration an object has as it falls to the ground is the same regardless of what the mass of that object is.* That result follows immediately in Newtonian physics, where the mass being accelerated by a gravitational force is in the numerator, and the inertial mass in the denominator cancel each other out. But how is this recapitulated in GR where there is no force of gravity? AG *> Things as they are, remain baffling. You just can't admit that you can't answer my questions. For example, how can an observer see a moving clock ticking slower than an observer in the moving frame, which is at rest with the clock in his frame?* *That's the twin "paradox", and if you really want to understand it then take a look at the following video, it's the best intuitive explanation of how it works that I have ever seen, and it proves that it's not a logical paradox at all, it's just odd. * Definitely NOT the TP. Generally, time dilation is a symmetric phenomenon, and remains so in the muon case, but in the TP the traveling twin goes through several accelerations to leave and return to meet his resting twin. So NOT symmetric. I don't think it's hard to show that it's the asymmetry which leads to the age disparity when the twins are reunited. It's the false assumption of symmetry that leads to the alleged paradox. AG *I Never Understood How To Intuitively Solve The Twin's Paradox ... Until Now! <https://www.youtube.com/watch?v=3V00tAfcHCI>* *You might also want to take a look at this: * *I Never Understood How Curved Time Creates Gravity… Until Now! <https://www.youtube.com/watch?v=OpOER8Eec2A>* *And this: * *I never understood why black holes slow down time...until now! <https://www.youtube.com/watch?v=k5H7UwSjdek>* *This guy has the ability to explain things very clearly. * *>> And classical electrodynamics could NOT explain how it could be possible that a negatively charged electron could orbit a positively charged nucleus because an orbiting object is experiencing acceleration do to the fact it is constantly changing directions, and classical electrodynamics says that an accelerating charged object, such as an electron, will emit electromagnetic radiation, lose energy, fall to a lower orbit, and spiral into the nucleus in 10^-11 seconds. * *> Does QM explain why atoms in motion don't radiate energy?* *Yes. Because an electron cannot radiate continuously because it is only allowed to be in certain orbits and radiate a certain amount of energy when it changes orbits. Why is that? Because the electron has wavelike properties, and its wavelength is h/p where h is Planck's constant and p is momentum. And if the electron is in a stable orbit then it must be in a standing wave because otherwise it would interfere with itself, so the circumference of the orbit must contain a whole number of wavelengths. And that causes the energy levels to be quantized. * I was careful to use the word "atoms". When you accelerate from a traffic light which turns green, the PROTONS in the nuclei of your car and body accelerate. Shouldn't protons, being charged particles, radiate energy when accelerated? I've heard on good authority from one of Brent's colleagues, that this is an unsolved problem in classical E&M. AG *>> When you touch a marble with your finger, why is a force applied to the marble? To really get to the bottom of that question you need more than classical physics, you need Quantum Mechanics. It's not because of electromagnetism which can be attractive or repulsive or zero if there is no electrical charge, and atoms have no electrical charge, and both your finger and the marble are made of atoms. **The real reason is because atoms have electrons in their outer layer, and electrons are fermions (that is to say they have half-integer spin) and so must obey the Pauli Exclusion Principle which says that two fermions cannot be in the same quantum state.* *> How does Pauli's Exclusion Principle prevent radiation loss due to acceleration? AG* *As I have already explained, Pauli's Exclusion Principle is the reason you can't put your hand through your desk or walk through brick walls. Discrete energy levels are the reason electrons don't radiate continuously and spiral into the nucleus. * I don't see the connection between the Exclusion Principle and the fact that electrons have discrete energy levels. AG *>> On the other hand bosons such as photons (that have integer spin) do NOT need to obey the Pauli Exclusion Principle, in fact in some circumstances they prefer to be at the same quantum state. In 1917 Einstein used that fact to discover the principle of Stimulated Emission, which is the operating principle behind the LASER, which is an acronym that stands for Light Amplification through Stimulated Emission of Radiation. **But why is the Pauli Exclusion Principle true? Because Quantum Mechanics demands that it be true. What demands that Quantum Mechanics be true? I don't know. * A *> when you're sitting on your butt, but time, the 4th dimension, continues to advance. Also, when I used the condition "at rest", I meant at rest on the Earth, or any other frame one might choose. AG* *>> On a space-time diagram you are always moving at a constant speed, the speed of light. When you're sitting on your butt all your speed is in the time dimension, but when you get up and start walking a small part of your speed is in a spatial dimension, so your speed in the time dimension decreases slightly. And that is called time dilation. * *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* ih7 -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/0a00b05a-54f1-409c-b15d-042efeb03932n%40googlegroups.com.
