# DanMP

Senior Members

305

1. ## Time and relativity (split from The Nature of Time)

Now you are insulting me. And this is the second time (remember rubbish). You are also wrong. I knew that "frequency is the reciprocal of time" from the beginning, that's why I asked: Your spectral lines are shifted for both gravitational reasons (as you said) and kinematic reasons (see here: Relativistic Doppler effect and Transverse Doppler effect). And the spectra you get are coming from individual atoms, with different speeds and positions. The fact that you didn't say anything about their velocities and altitude doesn't mean that they are not important. Ok, you may work with average velocities and average altitude, but this is an approximation, not at all like in the Moon-Earth experiment I'm proposing. I asked you about accuracy and you never answered. In the experiment I'm proposing is just a different scenario: 2 clocks on 2 different massive objects, not about a new level of accuracy, since there is no "first/older" level/range in this particular scenario. An artificial satellite is not a massive object. The Moon is. That's the big difference. Both Moon and Earth observer are seeing the other moving. Swansont said: "The moon is moving relative to us. How does kinematic time dilation not occur?". I responded that someone on the Moon can say "The Earth is moving relative to me. How does kinematic time dilation not occur?". Obviously, if there is any kinematic effect, it should be agreed by both. So you know if there is (should be) any kinematic effect in this particular scenario? Consider the clocks on the ground, at one pole (in order to be locally static).
2. ## Time and relativity (split from The Nature of Time)

It's not about the level of precision. It is just a new scenario, not tested, not "charted". And we don't (as far as I know) really calculated, using GR, the outcome. Even that may offer surprising results, because what your "intuition" told you may be invalidated by proper calculations. It is not about some data range, it is about not giving up testing QM although it was proven right time and time again.
3. ## Time and relativity (split from The Nature of Time)

You are joking me right? The spectrum collected from one star is not from one atom! There are many many atoms/clocks, not all at the same altitude and with the same velocity. Now you get it? Even if you can somehow deal with that, the problem is: what accuracy you can get, using spectrum lines and GR, regarding the speed of the star as a whole? And again, it was done? How the speed of the star matched the speed determined using other methods? By the way, how did we know the speed of the star? And what frame of reference was used? Since electronics depends on QM correct, we are already implicitly assuming that QM is correct if we send missions anywhere. But you aren’t suggesting that QM is in question on the moon, and needs to be tested. You didn't understand, again. You said/implied that GR needs no more testing. I said that QM is still tested, with high costs, even it was validated time and time again. Why investing (big money) in QM tests is ok, but in GR tests is not?

5. ## Time and relativity (split from The Nature of Time)

The Moon gravity well, not its speed, is special/different, compared to satellites. I wrote "approximately inertial reference frame" as they said about Earth's frame. Why one is OK and the other not-OK? Is the Moon fame OK? If not, why not? Did you make GR calculations, as you should, or you just applied Special Relativity? And, more important, how do you know for sure that it will occur before actually testing it? Also, the Earth is moving relative to the Moon, so according to the Moon observer the clock on Earth should be slower. As I said, with so many expeditions scheduled for the Moon in the near future, it would be cheap to do the test. I also said that the clock can be on the orbit around the Moon, not necessarily on the ground. The "kinematic time dilation" due to the rotation of the Moon around the Earth can still be assessed and tested.
6. ## dark matter question

But you can blithely rule out higher energy DM? No, that’s not how this works. Formulate a model where you form an atmosphere with DM, rather than declaring by fiat I didn't say that DM atmospheres should exist, not even that "we can not rule out DM atmospheres" as you took it. I wrote: I also wrote: so I kind of admitted the lack of "a model where you form an atmosphere with DM". In your opinion, the temporarily lack of a model about how something was formed is enough to rule it out? How Higgs field (or any field) was formed? Do you have/know a model? How the conditions for big bang were "formed"? By the way, do you have a model for "higher energy DM"? How/when the higher energy was acquired and why it doesn't decrease?
7. ## Time and relativity (split from The Nature of Time)

What 2 clocks? The lines in the spectrum are not from individual emitters. You don't know the exact position (altitude) in order to calculate gravitational time dilation. You don't know the exact speed in order to calculate the kinematic time dilation. And what accuracy you can get using this approach? What speed, perpendicular on the line between us and Sirius, was detected using this method that you claim it covered the test I proposed? And what other metod was used to determine that speed, in order to say that GR predicted the exact same speed? I wrote: and: In H-K experiment there is kinematic time dilation and gravitational time dilation. The same in GPS time dilation, where they offered calculations and they wrote: My question is: what if we choose a GPS satellite based reference frame? This is also an approximately inertial reference frame. In this case the Earth is moving, so the clocks on Earth should be slowed down ... I learned from another discussion that in fact: so my experiment (with one clock on the Moon) is actually a test for GR not for GR+SR and the things are not that simple: what reference frame should we use and why? What exact kinematic effects would the clocks register? It is different. See above.
8. ## Time and relativity (split from The Nature of Time)

I never contested gravity wells or something that you said, but how is this relevant to the experiment I proposed? There are parts/domains of GR never really tested, and this 2 clocks in 2 different gravity wells experiment/situation is one of them.
9. ## Time and relativity (split from The Nature of Time)

It is special because it was never done. Don't expect that, if not passed, GR is/was entirely wrong. Maybe just in need for little adjustments.
10. ## dark matter question

So you suggest that DM particles can form atoms? This is new. What force would keep the nuclei and the "electrons" together? And why not molecules and so on?
11. ## Time and relativity (split from The Nature of Time)

It is new because the clocks are in separate gravity wells. Never done before (as far as I know). If we never did such a test we don't know if GR would pass it. And GR is too important to us. As I said, with so many Moon expeditions scheduled in the near future, it would be not expensive. You wrote: Faster, yes, but GPS satellites are not massive objects, with big gravity wells. So, again, on the Moon would be other conditions (the separate gravity well), never tested before in this way. The speed is higher than in the original H-K experiment, so it would be enough, especially with long intervals.
12. ## dark matter question

This is a good point, but for me (thank you). Since we don't know any current process that creates DM particles (as we do for neutrinos), we may asume that they are "relic", having low energy/speeds. No, but nobody knows, so we can not rule out DM atmospheres just saying that neutrinos are not forming atmospheres. We don't even know that they don't, if we can't detect "relic" neutrinos. A DM/neutrino atmosphere may be much lighter than air atmosphere and "penetrating" under the surface, so it would be very hard to detect using just their gravitational influence. Just see how rapidly air density decreases as you go up ...
13. ## dark matter question

Citation please, from someone who has actually measured DM 'particle' velocities. I meant DM particles don't emerge from nuclear reactions, otherwise we could say "that one is a DM particle", and we would know much much more about them. About speed, we don't know much. At least I don't. Do you know someone who has actually measured DM 'particle' velocities?
14. ## dark matter question

Imagine a scenario in which Earth's atmosphere (the air) is as "visible" as DM. We would notice it due to discrepancy in the gravitational acceleration we have at the surface vs in orbit, or in other way? If the answer is yes, we would still notice it if its mass would be much much smaller and distributed with decreasing density from the center of the planet (not just from the surface) upward? The analogy is not good for many reasons: neutrinos are emerging with relativistic speeds from nuclear reactions, while DM particles don't neutrinos are not forming a galactic halo there is much more DM DM particles may be much lighter than neutrinos
15. ## Time and relativity (split from The Nature of Time)

You both seem to forget that the test I proposed is a (new kind of) test for GR, so GR specialists should make the predictions about the Moon-Earth clocks differences and see if the GR predictions are consistent with the reality/measurements. The Chinese sent a rover to the Moon, Artemis program just orbited the Moon and is planning to establish a permanent base camp on the Moon, so it would be very cheap to set up the experiment I proposed. If the scientists are not interested enough in GR (and more) in order to do it, they may lose much more time and resources going in the (possibly) wrong direction ... Remember that it doesn't matter how many test you passed if there is even one test that you don't. And I have to repeat, this kind of test was never done (as far as I know). The speed of the planes used in the Hafele-Keating experiment was smaller than the speed of the Moon around the Earth and they registered differences, so why you consider the speed (or angular momentum) of the Moon far too low to even make any difference? I understand that inertial mass is identical to gravitational mass and I never disputed it. What I don't understand is how the experiment I proposed (with one clock on the Moon compared for months/years with one on the Earth) can be done from Earth, with lasers.
16. ## dark matter question

We know the mass distribution that must exist for the rotation curves we observe. We can make a distinction between the mass of the massive object and the mass of its potential DM atmosphere in order to know that DM atmosphere is present or not?
17. ## Time and relativity (split from The Nature of Time)

The kinematic time dilation for the clock on the Moon I'm interested in is the one caused by the Moon rotation around the Earth. In order to calculate it we can also consider the case where the Moon is "hovering" (not rotating). The difference in time between rotating and non-rotating Moon. It would be big enough, especially for long intervals. We may set the clock on the Moon to send a signal at every exact 12 hours (or any other interval) for months/years. It doesn't. It may be on satellites around the Moon, or on/around any massive object other than Earth (where the other clock is). I have more GR tests in mind, most of them in space. GR is very important to us, so it needs to pass all the tests we can imagine. And I'm not talking about repeating in other locations the test we done. It's about new kind of tests. Some day I'll elaborate on this.
18. ## dark matter question

It may not because there is no friction to hold it there. How do we know that? DM particles may interact (collide?) with other DM particles or other weakly interactive particles: So, we know for sure that DM particles can not form atmospheres around massive objects (star, planets)? Galactic halos are not similar with atmospheres? We don't know how exactly DM particles are behaving when they get very close (in collision course) to other DM particles, nor to regular particles. It is not possible to "collide" with regular particles as a mosquito with a locomotive, not being noticed at all? Anyway, besides that we don't know exactly how DM atmospheres would/could form, we have some (observational?) evidence against them?
19. ## dark matter question

You seem to know a lot about DM, so maybe you can tell us more: DM particles attracted by massive objects, like stars and planets, may form DM atmospheres around them? If not, why not? If yes, can we make a distinction between the mass of the planet/star and the mass of its close DM atmosphere, the denser part (assuming that DM density increases towards the planet/star center, as for regular matter atmosphere), in order to account for all the dark matter? Since DM does not interact (except gravitational) with regular matter, it is possible that the above mentioned hypothetical DM atmosphere to be not only around the planet/star but also inside it? The estimated 90% includes that DM?
20. ## Time and relativity (split from The Nature of Time)

The experiment I proposed is also a Hafele-Keating type experiment, but the traveling clock would be in a different gravity well than ours. The kinematic time dilation caused by the moon rotation around the earth is the one of interest to me, not the gravitational components, so I don't think that local position invariance tests are helpful. The clock in the moon's gravity well may be on a satellite in close orbit around the moon, so it is less costly that you may think, and doable in the near future. Since no such a test was ever done (as far as I know), it may be important and the benefits greater than expected.
21. ## Time and relativity (split from The Nature of Time)

Yes, but sometimes you need to know/understand better the "territory". From a 2D map/representation of a mountain you don't know that maybe there is a tunnel there, between A and B. If you understand erosion and tectonic plates theory you can predict a future decrease/increase in height. In the same way, when we'll understand dark matter and/or we'll learn new things, maybe we will be able to have a better understanding and to make (and test) new predictions regarding relativity. We may even keep the GR "map" and only change the understanding. By the way, I don't think that our future is "written". The spacetime map that includes the future may be needed/useful, but ... don't confuse the map with the territory/universe.
22. ## Time and relativity (split from The Nature of Time)

I'm aware about the observational evidence and I wouldn't propose a theory inconsistent with it. I have to make a correction: the test with the clock on the Moon (and one on the Earth) is a test for both GR and SR. The clocks would be subjected to both kinematic and gravitational time dilation. The test with a clock on the Moon I suggested, is a kind of test that was never done, so don't treat it as trivial. As far as I know we never tested GR+SR measuring and computing time dilation for 2 clocks situated in separate gravitational wells. All our tests were inside Earth's gravity well, including the GPS clocks on orbit. The Moon is orbiting the Earth but it is massive, having its own gravitational well. This is the novelty. And it can be done in the next years. Why we shouldn't do it? Aha, there you said it, the model can no longer function, so GR/Einsteinian definition of time is required for the model, not for the gravity itself. You also: Of course not. How could you think that? admitted that the current relativity is not the ultimate theory for gravity, so you are admitting that it is conceivable to have a new & better theory/model, maybe with a different concept/understanding of time. So, as long as there is change, we can (and we kind of need) to define time. The way we define and use it can vary, so there is no need to cling on the current GR definition or any particular definition. As long as we can use it successfully, any definition works. I just remembered something: if GR definition of time is the "true" one, our future is already "written"?
23. ## Time and relativity (split from The Nature of Time)

Yes, but when you don't know how to explain why, you should be aware that your theory is very probable not the final/ultimate one. The more you can't explain, the more weak/vulnerable is your theory. GR also lack in evidence. Did we tested it using atomic clocks on the Moon? There are many tests to be done outside Earth.
24. ## The Nature of Time

I didn't entered in details regarding my theories and I won't (not even offer links), in order to respect the rules.
25. ## Time and relativity (split from The Nature of Time)

l wrote: and you can't deny that 😄 You are very attached to the current understanding/definition of time, the one used in GR, but you really think that this is the final/ultimate theory that we can have in order to explain gravity with all its aspects? There are already many complaints about it since dark "stuff" appeared. Some even say that dark matter is not real and is used to maintain GR valid (I don't agree but it is possible). There are MOND theories proposed. There are other attempts also, including my theory, based on dark matter. Moreover, if the GR definition/notion of time is "the one and only", please explain how is this particular definition (the notion of space-time) used in quantum physics. Also please explain why, and how exactly, gravity wells are formed around massive objects and why exactly is the speed of light invariant? If you don't have an explanation, how can you be so sure that GR is the ultimate theory? With my theory I explained them fairly easy. My opinion about time is that it is something we cannot see, touch, feel in any way. What we can see/observe is change. Because there is change, we can invent/define time as an useful notion/tool. We need it to compare changes (faster/slower), both in position (movement, speed, acceleration) and in structure (ageing, decay). We need it to make our theories, for our equations, for accurate predictions. And we also need it to write our history in chronological order. Last but not least we need it to function, to catch a train, to meet someone, to plan a trip, etc. So time is as real as density, or pressure, or temperature, but more important. Gravitational radiation? You mean gravitational waves? If so, what is the explanation for them? The space-time vibrates? How? You are absolutely sure that there is no other possibility to explain gravitational waves (outside GR)? How can you be? ( I have one, not the one I wrote here, that one was wrong).
×