DanMP

For DM particles, as I wrote above (see especially what I underlined), the photons "inside" time is very very short and the same for all frequencies, unlike the "inside" time for atoms and molecules. So, the index of refraction in DM gas is the same for all frequencies. No different speeds and no "rainbow" at the refraction responsible for gravitational lensing. Also, the change in direction (dispersion) is very limited. I'll be busy next days, so I won't be able to reply for a while.

Exactly (thanks), I just tried to describe what is happening. I know it sounds silly, but I consider the DM particle as a very stable "system". When a photon gets in, the particle/ system becomes unstable and promptly "spits" the photon out. Don't ask me how, because it's like asking Koch when he just discovered bacteria about its DNA. Take it as a definition of my model. Let experimental tests I proposed to decide if the model is good. You need a clock to measure the mirror speed. So it's not much different than the Fizeau apparatus in the opening post. You obviously didn't read what I wrote 6 years ago. I explained/proposed that, in the Hafele-Keating type experiments, kinematic time dilation is caused by the movement of the clock through Earth’s DM gas atmosphere, the reason being easy to explain with a light clock (the original use of the light clock). So, in very high orbit, where the instrument/clock can be surrounded by its own, comoving, DM atmosphere, there is no movement of the clock trough DM gas, hence no kinematic time dilation. Simply to detect but/and never attempted.

Quasi (or failed) absorption immediately followed by re-emission is not scattering. The definition of scattering is: "the process whereby a beam of waves or particles is dispersed by collisions or similar interactions". There are no collisions ... and the change in direction at re-emission is very limited, because the time between quasi-absorptions and re-emissions is too short. Normal matter, as opposed to DM, can form atoms and molecules, structures able to use (actually absorb) the photons if the photon energy is the one needed by the electron to "jump" to a higher energy level. So, the time between quasi-absorptions and re-emissions is longer, giving the time for the electron to move around (Bohr model) and emit in other directions than the original. The time needed to "decide" if the photon can be used depend on its energy, therefore light/photons travel at different speeds in transparent materials and the refraction is energy/frequency dependent. DM gas atmosphere, like any atmosphere, is denser near the massive object it surrounds (like stars, planets, black holes) and, going upward, gets less dense. The gravitational time dilation is therefore greater near the massive object and smaller as we go up. No contradiction with reality. They are all equally affected. Please read my explanations for the invariance of the speed of light in vacuum posted 6 years ago. I really have not enough time to write/explain everything again. When I'll have time, I'll try to cover/explain what I didn't.

If you read what I wrote 6 years ago, you understand how. In short, I proposed that light, actually the photons, travel through both ordinary and dark matter, by quasi-absorptions quickly followed by re-emissions. DM particles never really absorb photons, so the tiny delay of each such interaction is the only effect (in fact this causes one more, a refraction, responsible for gravitational lensing). I initially used this idea for ordinary matter, successfuly explaining (with math and all) the Fizeau experiment and the Sagnac effect. You should read what I wrote 6 years ago ... Maybe, but the Earth centered non-rotating frame is the one we usually choose (although the clocks at rest in the dragged frame would be the fastest ... while rotating - with respect to distant stars - and having centripetal acceleration ...). Ok, I admit I didn't quite understand, so please elaborate. Also, my questions, even seemingly unrelated, still stand. See the beginning of this post.

I really appreciate you and your effort to find and offer links to interesting papers regarding relativity, but after following at least 3 of them, I realized that you didn't notice the requirment to prove/disprove my DM gas theory. We need to measure the time in a very high orbit, in a place where the Hill sphere of the instrument/satellite is large enough, because otherwise the instrument/satellite cannot have it's own DM atmosphere. If/when the instrument/satellite has it's own DM atmosphere, the kinematic time dilation dissappears, because the instrument becomes static in relation with the DM atmosphere surrounding it. That's it. It is a simple, powerful experiment, and it was never done. When there is no own DM atmosphere, there is absolutely no reason to disagree with GR. As for the Moon and other distant celestial bodies, like stars, we only have indirect measurements, redshift observations, and the redshift is caused by many different things, besides kinematic time dilation. It is impossible to exactly tell how much of it is from kinematic time dilation. Also, the observations are flawed by the fact that we obtained our data considering the kinematic time dilation as existent. And, when the data disagree with our theory, we usually add a peculiar velocity ...

You obviously didn't read/understand what I wrote. I presented a thought experiment (there is no actual Fizeau apparatus) aiming to show why the speed of light in vacuum is invariable, not to deny it. The title of this thread is wrong/misleading. It should be: "A thought experiment meant to show that c invariance and gravitational time dilation are caused by a dark matter atmosphere". Being now in the speculation forum, I can be less subtle. Let's try again. In a box we have an imaginary device that is sending a pulse of light towards a mirror and receives the pulse reflected by the mirror. In vacuum, the total time from emission to detection is exactly 3 nanoseconds (as explained in the first post). The light clock is "ticking" exactly 3 times. The atomic clock situated on the same table agrees. Now, we introduce a gas in the box, a gas that is not detectable (like DM), but makes the light travel slower, exactly as any known gas would do. The light clock would still tick exactly 3 times (3 ns) for a round trip of the light pulse in the measuring device, so, for the people in the box, the speed of light in what they think is vacuum, is invariant. The atomic clock would measure more than 3 ns, and everybody is wondering why the speed of light in what they thought is vacuum, is decreasing. Not knowing about the DM gas, they declare that the space is warped, and this is what GR pretends to happen in the regions where in fact light is traveling slower due to the increase density of the DM gas. In real life, the atomic clock is also affected by the DM gas, because, being made of extremely tiny particles, the DM gas cannot be contained. So, if you measure the speed of light in "vacuum" at the sea level, you get c, but only if the clock is also at the sea level, at the same DM gas density. If the clock you use is on a mountain top, at lower DM gas density, you obtain a value lower than c for the sea level speed of light in "vacuum". You know any thing or device that can be used to measure the time and is not made of parts held together by a force that is transmitted similar with the light in vacuum? Even if you know one (the muon?), how can you be sure that the proposed DM gas has no influence? You obviously didn't read what I actually wrote: Read what I underlined. I wrote that it's not true and I presented one reason (there are more). So, your comment, although good and interesting (thanks), was uncalled for. So, the electromagnetic force acts/propagates slower than light in vacuum? Ok, but you should notice that in real life there are preferred frames. See the Hafele-Keating experiment. The relevant frame there is exactly the DM atmosphere I'm proposing. It is a kind of aether, but one that not only agrees with Lorentz transformation, time dilation, and so on, but is also explaining them. Follow the link to my theory I provided. I'm pretty sure that no one searched the experimental test I offered/mentioned, so here they are: Thread 'Suggestion for 2 more GR tests' https://www.physicsforums.com/threads/suggestion-for-2-more-gr-tests.1056055/ Thread 'Time dilation in a planet-moon system' https://www.physicsforums.com/threads/time-dilation-in-a-planet-moon-system.1053613/ https://www.physicsforums.com/threads/is-there-an-atomic-clock-experiment-on-the-moon-testing-relativity.1053545/

Yes, of course, but simple math/simulations are easier to master, as opposed to: I wrote "the invariance of c" for briefness. I meant "the invariance of the speed of light in vacuum" and I propose the following way to reassess that: First, you must make a step back, forget/ignore Einstein's space-time and equations. Remember only the facts, like time dilation. Then, you should observe that we measure the speed of light in vacuum using instruments made of atoms and molecules, held together by the electromagnetic force, a force that propagates (is transmitted) with exactly the same speed we need to measure. Now, I propose a thought experiment, with light clocks: (the same clocks we used to explain kinematic time dilation). We take one light clock with the distance between mirrors 14.9896229 cm (29.9792458/2). Then we put it in a box, together with a measuring device for the speed of light, something like the Fizeau apparatus: with the distance between the toothed wheel and the mirror 3 times larger: 3x14.9896229 cm (remember that this is a thought experiment ...). Now we pump the air out of the box, creating a vacuum. The round trip from one mirror of the light clock to the other and back again will take the light pulse exactly 1 ns, in agreement with an atomic clock nearby. The light in the measuring device would need exactly 3 ns, 3 "ticks" of the light clock, to travel to the mirror and back, confirming that the speed of light in vacuum is 299,792,458 m/s, c. Now we start to let air in the box. If we measure the speed of light, with the Fizeau apparatus in the box, using the time provided by the atomic clock nearby, the value gets smaller, but if we use the light clock next to it to measure the time, the speed of light remains c, regardless of air pressure/density. We can even insert water. It will take exactly 3 "ticks" of the clock situated in the same environment, for the beam of light to complete a round trip from the toothed wheel to the mirror and back. So, the speed of light appears invariant when measured with instruments working based on exact same speed. Maybe the invariance of the speed of light in vacuum is a consequence not an enforced law ... Furthermore, we notice that the light clock is "ticking" faster in vacuum than in air. We can clearly see this by adding an identical light clock that is kept all the time in vacuum. As we increase the air density in the first box, the respective clock "ticks" slower and slower (when compared with the one in vacuum). This may suggest that an atomic clock situated at a high altitude (top of a mountain), where the air density is lower, is ticking faster than a sea level clock (as in gravitational time dilation) due to air density. Of course, this is not true, one reason being that there is no air inside the atoms of the atomic clock (the air is made of atoms and molecules, too big to get inside other atoms and molecules). In Einstein's time, that would have been the end of the story (thought experiment), but now, more than 100 years later, we know that there is something called dark matter, something that is gravitationally attracted, forming roughly spherical halos around galaxies, exactly how a gas would do. The fact that we cannot detect DM particles may mean that their mass/energy is very very small, so, in order to make more than 5 times the mass of ordinary matter, there should be in huuuuge numbers and slow moving (with small kinetic energy, "cold"). So, it is not impossible to exist a dark matter atmosphere around the Earth, made of particles small enough and plenty enough to fill the space inside atoms/molecules, and with densities decreasing from the sea level up ... If you want to learn more, read what I wrote in Speculations, in august 2018, and search the experimental tests I proposed in Physics forums, as DanMP, just before I was kicked out (not because I violated their strict rules, but because they learned about my theories posted in this forum ... By the way, this is another reason why foundational physics is stuck: the high level physicists tend to reject not only different ideas, but also uncomfortable questions and experimental test proposals).

I don't quite understand what you mean, but the fact that "GR did not come from Newtonian physics" shows that a new theory may have a completely different approach. GR geometric approach was needed because at the time it was adopted it was not possible to find another, better one, because they didn't know about DM. Usually, when you feel that the way you took may not be the good one, you simply go back a bit and try another route. This was/is my suggestion, to make a step back and retry. The simulations I envisioned require simple math and real particles. I don't know about you, but I consider DM particles as real, as opposed to virtual or invented. Their proprieties cannot be found directly, so the alternative is to imagine/define a model and test it. Something similar was done for quarks. I'll explain it soon (within a week). Now I really have to go.

I wrote that any new theory must be in agreement with all the old experimental data, in other words to be consistent (compatible or in agreement) with all that we observed and measured before (in that particular field). I really don't understand why your reply is "Newtonian gravity did not give us GR". Newtonian gravity and GR are theories, not experimental data. Experimental data does not belong to a theory. Ok, GR proposed new experiments, that were confirmed. This is why I wrote "and then to predict things that can be experimentally tested afterwards". To give an example, MOND theories are able to explain the rotation curve of a disc galaxy, and more, but, being gravitational theories, they must also explain gravitational time dilation and gravitational lensing. I proposed to reassess the things more or less explained long time ago, like the invariance of c, having in mind DM, etc., as opposed to "randomly and blindly groping in the dark by inventing maths that don’t seem to be motivated by any real-world data points, hoping to just stumble across that next breakthrough". I can describe what I meant when I suggested to focus more on actual physics. I meant to work with real elements/particles (as opposed to virtual/invented), to define their behavior and how they interact, and then make computer simulations in order to check and refine the model. GR is purely geometric and the fields are like Greek gods (they are invisible but very potent, they interact with each other, they have well defined tasks and magic abilities). The situation in physics today may be similar to the one in medical science in Robert Koch's (one of the main founders of modern bacteriology) time. Before him, it was believed that illnesses are caused by bad air or by gods/demons (invisible, invented entities, like the fields are). Koch discovered bacteria and showed that not invisible, invented entities are causing the illnesses ... I think that DM particles can be used to explain things better than the fields we invented and the abstract geometry we created. Yes, you finally got it (any new theory must be in agreement with all the old experimental data). Yes. I meant all experimental data that concerns the new theory/model, not all the experimental data in all science, nor the previous interpretations of experiments.

Any new theory must be, first, in agreement with all the old experimental data, and then to predict things that can be experimentally tested afterwards. Yes, but this leaves room for new theories, theories that can explain more. Probably it's impossible to explain everything, but we can do more than we did so far. Yes, I didn't read many of your posts, so I really don't know/remember your pov. Anyway, my questions were not directed to you or any person in particular. I just explained why I think that it is still room for new foundational theories. My understanding of fields is not good. Perhaps that’s why I don't like them. Unfortunately no. In fact this may be the sign that we climbed in the wrong fruit tree 😀

There is no experimental data?!? So there is no experimental data to back GR? 😀 What in the world are you talking about?

You got it all wrong. The theory is (should be) a physical model. Yes, it usually includes math, but it isn't just math. And who said that "there’s no experiment" ?! I said:

Against reality (experimental data), of course. Why? The fact that current theories are not actually explaining the reality. Can you explain what a field is and how exactly a force is transmitted at a distance? Can you explain the invariance of c? Can you explain how a mass is warping spacetime? And no, I'm not asking how the model works, I'm asking what and how is really happening. Also, in the string theory, why the strings are vibrating? Anyway, it seems that I'm not the only one to expect more, better, models.

My input was related to that, so I wasn't off topic. We need to focus more on physics and less on math.

The rules were told and this is also what I said/implied. One may define/set the rules & model and check them using simulations.