General > General Technical Chat
"Veritasium" (YT) - "The Big Misconception About Electricity" ?
aetherist:
--- Quote from: TimFox on March 03, 2022, 04:01:38 am ---"The self-adjustment via a control would overcome ticking dilation from other parts of the clock, but of course we would still be left with the ticking dilation of the control itself."
Could you re-phrase that statement so that it makes some sense?
The reason why the definition of the meter was changed was that with cesium atom clocks, the repeatability of the "second" is better than the old repeatability of the speed of light measurements based on the wavelength definition of the meter.
Have you ever seen a description of the way in which the speed of light was measured by simultaneous measurements of the temporal frequency and spatial wavelength of a "dye-stabilized" laser beam? It was a very clever straightforward measurement, applying a microwave frequency to an electro-optical amplitude modulator that produces a "carrier" center frequency and two "sideband" frequencies, in the same manner of an AM radio system.
You adjust the microwave frequency (with a servo) to get an interferometer to lock up on all three frequencies, then measure the characteristic length of the interferometer with a tape measure to determine the integers that define the relationship between the frequencies. No handwaving required, just arithmetic. See: https://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/measure_c.html
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For sure the new definitions must be a hell of an improvement in lots of way. I am not saying that i understand them. And i am very impressed with modern science. I love it. Can't wait for JamesWebb to moider the bigbang.
But science will find it difficult to advance in some areas unless it dumps Einsteinian stuff, & acknowledges the aether, & the aetherwind. And electons. In fact i am sure that science has dumped much of Einsteinian stuff, & they just pretend (is it to keep the Ruskis off balance?). And, the Ruskis are playing the same game. Spy versus Spy.
I suppose that until recently they used Michelson's interferometer to measure length, & the speed of light.
The same Michelson interferometer that Michelson used to show that the speed of light was c+V & c-V (but he was ignored)(but for some silly reason he called that a null result)(silly boy)(& Lorentz was even sillier, not calling out silly Einsteinian relativity)(i blame Lorentz more than i blame Michelson).
But no matter how good or smart the standards, there will always be a need to allow for the aetherwind etc.
penfold:
--- Quote from: aetherist on March 03, 2022, 02:42:52 am ---[...]
A year ago i made an Excel of electrons bumping electrons, where each electron influenced 3 electrons ahead. But i had a look at my effort recently & i couldn’t follow my methodology.
[...]
--- End quote ---
Before I forget also, a couple of book recommendations to round off. The first one, probably not entirely relevant, "An Introduction to Mathematical Logic", lots of authors have written books with that title and function, the one on my shelf is by Richard E. Hodel and it "isn't bad", not without its critiques, but relates to what I've mentioned a little about the arbitrariness of numbers (squiggles on paper) and the strength they are given when related to numbers of chickens, lengths made of numbers of stacked wavelengths... you'd get a more explicit explanation from one of metric spaces, but that would get very abstract very fast.
The second one, on geometric algebra, a generalisation of vectors that allows both vector spaces and space-time-like spaces to exist. "Geometric Algebra for Physicists" by Doran and Lasenby is an exceptional treatment of that, it is neither completely abstract nor does it try to force "visualisation of it" (perhaps one of the reasons GA/Clifford/Quaternion representations of Maxwell failed early on), it just presents it as a tool and one that is far more powerful than euclidean vectors. GA isn't necessarily 'easier' than conventional vectors, but they're not difficult for standard 3D stuff and expanding beyond whilst not constraining to space-time and clearly seeing the implications of going space-time or non-space-time. The first few chapters (I think) should be appreciatable if not studyable by someone who can grasp at least complex numbers and geometric concepts of lines, planes and cubes etc.
Both books are quite expensive to buy but pdfs are available... somewhere, and Doran's doctoral thesis on GA for physicists and engineers is freely available... I'll drop a reference link if I remember.
adx:
I think I'd be interested in those too, whether I would do them justice in practical application of time spent learning, I don't know. My comprehension of maths is limited, not because I don't understand it, but because it comes across as thoroughly unnatural (difficult and unpleasant) to me and I don't really know why. Perhaps somewhere on the dyscalculia spectrum, if there is such a thing. It's sort of like the way some computer languages seem arcane and inside-out in the way they go about things, while for others at least I find I can pretty much write things in my sleep. Some people (usually non-engineers) are surprised an engineer could function without maths, but most I know don't use it in the sense of deriving anything symbolically. Just punch the numbers into the formula sort of stuff. I'd rather understand what the numbers mean than be subordinate to equations, if I had to choose. I can't see that working for a career in physics though! I came unstuck trying to follow GR all the way through for that reason.
Anyway, the reason for going on about that, is to recommend to anyone attempting to get a handle on EM signals (what is being sent and received), to learn what "AC" and "DC" means, in terms of the Fourier transform. Its Wikipedia page starts ok but explodes into gobbledygook for someone of limited mathematical training or ability. The Discrete Fourier transform page is still full of weird looking stuff that I have to assume I would have not a hope of getting into if it wasn't already second nature. The Fourier series page shows some nice diagrams and animations which come closer, but the almost trivial computation of a DFT becomes lost in the well-meaning mathematical rigour - my point is to say that these concepts are not difficult but need to be appreciated quantitatively somehow when talking about things like "frequencies".
penfold:
--- Quote from: adx on March 03, 2022, 11:43:04 am ---I think I'd be interested in those too, whether I would do them justice in practical application of time spent learning,
[...]
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To be quite frank, in a professional 'engineer' sense, me neither, not even Poynting. Never in a circuit have I ever needed to calculate or visualise a Poynting vector, not at 6GHz, not at DC and not between - it would be difficult to say I was doing the design a particular disservice by not doing so because it passed all of its tests and general aetherial effects didn't affect its function in an observable sense. I suppose the same design may not be suitable to use next to an arc welder heading at c/2 towards the sun - but the client didn't ask for that - a thorough EM study isn't cheap and less so if it doesn't fall with an OTS software package's remit. Any serious maths, with me, is just an artefact of an overly academic start and a bit of lingering cross-over.
Book recommendations were also partly an "I'm too lazy to reference, you'll likely find justification of anything unfounded in there". Interestingly as you mention DFTs, I remember finding myself in a maths lecture, it was offered to 4th year EEE undergrads and I assumed it would be delivered as such (I was very wrong, it was 'also' for 4th year maths undergrads who had a very different level of rigger). Long story short was that as the lecturer was going through this derivation involving vectors and a discrete signal, when he got to the end I suddenly realised "whaaa?! a 1024-point DFT is just a 1024-dimension vector... with 1024 components... that represents the 1024-dimension signal vector... nooo, how can this be, it's frequency components!".
I'm just musing, not advocating or selling any perspective. A similar view as the FFT being strictly-frequency-components-only being ripped apart and reduced to a literal "transformation" of vectors, change of basis (i, j, k,etc.), etc, and removing all conventional interpretation of numbers/mathematical-symbols/signals is kind of similar to some of the alleged reasons that Maxwell's equations isn't Maxwell's Equation today and one of the alleged reasons that special relativity had such a rocky start (and still falls away from the side of intuition). (Clifford, Grassmann and Hamilton were the big proponents of a not-only-euclidean view of vectors).
In a geometric algebra, Maxwell reduces to a single equation, but still, splinters out into all 4 (or 8 or 12... I forget how many Maxwell came up with) 'classic' ones (and doesn't necessarily simplify under-grad worked examples).
GA does all that at the cost of losing easy interpretations of 'vectors' as describable with 3-rulers at right angles but makes it very intuitive to express them mathematically as 3 planes, one each with an axis for the x/y/z or i/j/k components where the second axis in each plane is time... making space-time intuitive but a game of battle-ships very difficult.
I'm losing the tenuous connection to the thread now, seemed interesting how sometimes the importance of relatability and observability are both fundamental requirements of physics and also sometimes a weakness.
aetherist:
--- Quote from: penfold on March 03, 2022, 09:18:47 am ---
--- Quote from: aetherist on March 03, 2022, 02:42:52 am ---[...]A year ago i made an Excel of electrons bumping electrons, where each electron influenced 3 electrons ahead. But i had a look at my effort recently & i couldn’t follow my methodology.[...]
--- End quote ---
Before I forget also, a couple of book recommendations to round off. The first one, probably not entirely relevant, "An Introduction to Mathematical Logic", lots of authors have written books with that title and function, the one on my shelf is by Richard E. Hodel and it "isn't bad", not without its critiques, but relates to what I've mentioned a little about the arbitrariness of numbers (squiggles on paper) and the strength they are given when related to numbers of chickens, lengths made of numbers of stacked wavelengths... you'd get a more explicit explanation from one of metric spaces, but that would get very abstract very fast.
The second one, on geometric algebra, a generalisation of vectors that allows both vector spaces and space-time-like spaces to exist. "Geometric Algebra for Physicists" by Doran and Lasenby is an exceptional treatment of that, it is neither completely abstract nor does it try to force "visualisation of it" (perhaps one of the reasons GA/Clifford/Quaternion representations of Maxwell failed early on), it just presents it as a tool and one that is far more powerful than euclidean vectors. GA isn't necessarily 'easier' than conventional vectors, but they're not difficult for standard 3D stuff and expanding beyond whilst not constraining to space-time and clearly seeing the implications of going space-time or non-space-time. The first few chapters (I think) should be appreciatable if not studyable by someone who can grasp at least complex numbers and geometric concepts of lines, planes and cubes etc.
Both books are quite expensive to buy but pdfs are available... somewhere, and Doran's doctoral thesis on GA for physicists and engineers is freely available... I'll drop a reference link if I remember.
--- End quote ---
I use Excel to do my calculations to help me to avoid equations. Using lots of small iterations (using say Newton's F=ma) using Excel is a substitute for my lack of calculus, especially re integration.
I had a look & i see that i have over 600 Excel files on my computer, trying to solve say 100 problems that i came across.
I used Excel to check Einstein's stuff, especially re bending of light near the Sun. This might have been the epitome for my use of Excel. It showed that Einstein's equations etc did indeed give double the Newtonian bending.
And it confirmed that Prof Poor stuffed up his analysis of Einstein's equations for bending (Poor said that the postulates behind the equations did not give the bending equations)(but he left off one little term)(easy done).
And i have used Excel to look into the behavior of my electons, compared to old (electron) electricity.
Plus as i said i used Excel to look into 3 electrons bumping 3 electrons to help find the speed of old (electron) electricity.
I made my own Excel programs for calculating say Coulomb force etc. But nowadays there are plenty of online calculators for almost everything.
I was amazed at how say for energy versus momentum including friction heat loss i could do a very rough Excel (using just say 10,000 iterations instead of 100,000) & still get accuracy to say 12 decimals.
Unfortunately Excel only works to 15 decimals & so it aint much good for most of the Earthly relativity problems that come up -- these need at least 16 or 17 decimals (close).
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