DanMP

I think the best answer until here was the one exchemist offered: So, the vibration that makes the friction with the table almost zero is from the "high frequency alternating magnetic field". You wrote "Driving Frequency approx. 5 KHz". See here that the sound/vibration in your videos has about 5 kHz. The external force that causes the slide may be gravitational (you didn't show with a bubble level meter that the table is perfectly horizontal) or/and magnetic ("I notice the table has metal legs and that there are various large metal components also on the table").

Not totally off-topic:

It doesn't but thanks anyway. It sounded elaborate Ok, I knew that, but I think that behind any principle should be a reason, an explanation of what and why is actually happening. Wow! This is the best explanation. Thank you! +1 Another nice, comprehensive and useful explanation. Thanks! The underlining is mine and I did it because, in my opinion, the model, not the universe, cannot have only three spatial dimensions. And, as far as I know, this isn't the only possible model, there are graviton-based models in progress, modified Newton models and string theory attempts. Now I want/need to explain what I meant in my first post: in our world there are things we can feel, like apples and rocks, very real, things we define and measure, like temperature, pressure and time intervals, real enough, things like math, science models and words, real to us, humans, and very useful/powerful, but created not discovered, and things we created/imagined for fun, like unicorns. All these things exist for/to us, but they are not on the same footing. We kind of feel space by moving through it in all directions, so space is very real. In time we cannot move backwards, stop or "accelerate" forwards, so it is different. Needed, but different. In my opinion time is about change and the rate of change. We can observe change, so change is very real, but time is something made/created/defined by us in order to characterize the change, so it's less real. This is what I meant. In my understanding, to go back in time is to reverse all the changes in the whole universe. Do you see it different? How? And the last thing, if spacetime is not just a "tool" in our models, does it mean that the future is already "written", present in this spacetime?

I didn’t say anything about biological ageing, which is a different matter. The principle of extremal ageing means that a test particle under the influence of gravity will tend to trace out that world line in spacetime which represents an extremum of proper time,... (Emphasis mine) Why "a test particle" would do something so elaborate? And how it knows how to do it, or to "tend" to do it? Why not? This reminds me something that may interest you: https://science.sciencemag.org/content/329/5999/1630

Yes, time intervals are what we measure/observe. For this reason I said that time has a meaning when it's about time intervals. No disagreement here Regarding "time as a dimension" and its role in gravity: I'm not so convinced, probably because I don't know/understand enough. By the way, I admire your knowledge and the fact that you take the time to share it with us. I have some questions about spacetime (how/why exactly is warped around massive objects and why/how "the principle of extremal ageing" is imposed) but I don't want to hijack the thread, so don't answer this questions here if you think that this is not the right place.

Time does exist, like temperature, pressure, the word time and so on, because we defined them. Space is real because we can move left-right, forward-backward and up-down. In "time" we can't move backward, so it's not as real as the space. Time has a meaning when it's about time intervals, like distances in space. Time as a dimension has less or no meaning. Yes. You can find in this forum my alternative theory, based on dark matter. It is intuitive, it is in agreement with the experiments/facts and it offers new experiments, able to prove it.

If special relativity and all associated concepts such as Lorentz transformation, time dilation, length contraction ideas have been invalidated by your new theoretical framework, how you explain time dilation experimental confirmations (e.g. Hafele–Keating experiment)?