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I wanted to run the numbers again and realized I had garbled the equations somewhat.
I didn't realize the Nav had slipped in the equation for Earth's gravity into the mix. Since that's 10,000 times stronger than any of the other forces involved, it isn't really relevant, unless you're trying to calculate the actual tide heights. Here's the numbers I'll use. These don't really have enough precision to do this properly: Gravitational Constant G 6.67x10^-11 Mass of Moon M 7.35x10^22 kg Distance to Moon R 3.8x10^8 m Radius of Earth r 6.3x10^6 m Earth center to E-M barycenter s 4.641x10^6 The proper formulas for the Moon's effect a Farside: GmM/(R+r)^2 - m s omega^2 Near side: GmM/(R-r)^2 - m s omega^2 This does not count the Earth direct force, which is huge, and use a constant Centrifugal Force. I'll work this in terms of the acceleration felt by a body, which is numerically the same as the force on a one kg body. All numbers are m/sec^2. The CF comes out to 3.29x10^-5 . This is using an orbital period of 27.3 days (not the 28 nav mentions) The gravitation acceleration using GM/r^2 is 3.39x10^5. These numbers are actually the same, differing only due to the rough approximations used. They must be the same, because the orbital velocity is determined by the gravitational pull. Thus, we can use the number computed with GM/r^2. So, the nearside acceleration becomes: GM/(R-r)^2 - GM/r^2 = 3.51x10^-5 - 3.39x10^5 = 1.2x10^-6 for the farside: GM/(R+r)^2 - GM/r^2 = 3.28x10^-5 - 3.39x10^5 = -1.1x10^-6 Thus, the net force is almost equal and opposite, and in agreement with the traditional values. (The difference between near and farside may even be less, given roundoff issues.) If, however, we used Nav's equations, the number are radically different. The Nearside CF for Nav is (r-s)omega^2, or 1.17x10^-5 The Farside CF is (r+s)omega^2 or 7.74x10^5 Nav said this must be subtracted from the Grav force, which would result in: Nearside 3.51x10^-5 - 1.17x10^-5 or 2.34x10^5 Farside 3.39x10^-5 - 7.74x10^-5 or -4.46x10^-5 Note that this is a serious imbalance between near and farside, which is certainly not supported by observation. My hunch is that Nav would prefer to ADD the nearside grav and CF, which would result in 4.68x10^-5, which is close enough to the farside to actually make some sense. However, this is roughly 40 times the traditional value that has been used for many years. Many calculations have been presented that show the traditional values generate the observed tides; Nav has not presented any credible explanation for how the experts could be off by a factor of 40. But, lets take this one more step. What is the contribution from the Sun? First, running the net gravitational and Centrifugal forces at the Earth's center yields 5.93x10^-3 for grav, and 5.94x10^-3 for CF. Again, these numbers must actually be equal. The next step is to calculate the differential gravity. Frankly, since that is so small compared to the direct gravity that using these approximations would be futile. I'm content to accept the traditional value: the Sun's differential gravity is a bit under half of the Moon's, which would be about 5x10^-7. Finally, to calculate the Centrifugal Force from the Earth-Sun system according to Nav's formula, we can take advantage of the fact that it is linear with distance. The delta from the CF at the Earth's center, according to Nav, will be small, 2.5x10-7. On the near side the tides would be reduced by this amount, on the far side they would be increased. When added to the Differential Gravity, the net result is the farside is increased to about 7.5x10^-7, and the nearside is reduced to 2.5x10^-7. This presents the problem that the night tides have triple the contribution from the Sun as the day tides. Using Nav's formulas for the tides pass one test: the near and far side contributions from the Moon are roughly equal. However, in all other regards they fail miserably. The are 40 times the accepted and well studied values for tidal forces. But worse, the Moon's contribution is 100 times the contribution from the Sun. I don't there is any way to reconcile these discrepancies, and Nav doesn't seem willing to explain it. |
Ah ****;
I wonder just how many Tides will come and go before we even agree on a formular to figure God only know what. When, and if, a formular is arrived at, I really wonder if and what it will address? Will it have anything at all to do with the original question; "How can I sail a Tide Ride?" I DON'T THINK SO!?!? Was it worth a "Donal 1/4 Point?" I DON'T THINK SO????? Did we learn anything? I DON'T KNOW?? Maybe. Is It correct; I DON'T THINK SO!?!? Signing off, Ole Thom |
Sorry Thom, you really don't have read through the math if you don't want to. I have
to wear my sea boots to wade through the muck of political discussions and worse here, so you can humor my occasional technical obsession. As I've mentioned before, this is the kind of work I did before retiring, and although I don't miss the nine to five, I do miss the intellectual challenge of working through the problems. As for agreeing on anything, its a basic fact of human nature that there will always be disagreement, even on the most obvious truths. I view this a good thing, but it does mean that there will always be people who refuse to accept what others take as a given. This however, doesn't explain why some people are always wrong! "Thom Stewart" wrote in message ... Ah ****; I wonder just how many Tides will come and go before we even agree on a formular to figure God only know what. When, and if, a formular is arrived at, I really wonder if and what it will address? Will it have anything at all to do with the original question; "How can I sail a Tide Ride?" I DON'T THINK SO!?!? Was it worth a "Donal 1/4 Point?" I DON'T THINK SO????? Did we learn anything? I DON'T KNOW?? Maybe. Is It correct; I DON'T THINK SO!?!? Signing off, Ole Thom |
Jeff,
Hey, my friend, you're welcome to all the "net space you want. Just hope you don't mind being reminded about the reason the question was asked. I know if I had to calculate all those figures (Right or wrong) the Tide would have at least turn once if not more. Have at it my friend, I'll try to keep up but remember, I have a Web TV. No computer Ole Thom |
"Jeff Morris" wrote in message ... As for agreeing on anything, its a basic fact of human nature that there will always be disagreement, even on the most obvious truths. I view this a good thing, but it does mean that there will always be people who refuse to accept what others take as a given. This however, doesn't explain why some people are always wrong! I agree! Regards Donal -- |
"Donut" wrote
This however, doesn't explain why some people are always wrong! I agree! Well, you're wrong! |
"Scott Vernon" wrote in message ... "Donut" wrote This however, doesn't explain why some people are always wrong! I agree! Well, you're wrong! Perhaps you're right. Can you justify your position? Regards Donal -- |
"Donal" wrote in message ... "Scott Vernon" wrote in message ... "Donut" wrote This however, doesn't explain why some people are always wrong! I agree! Well, you're wrong! Perhaps you're right. Can you justify your position? Sitting down, facing NNW. Scotty |
"Scott Vernon" wrote in message ... "Donal" wrote in message ... Can you justify your position? Sitting down, facing NNW. Dammit! I thought that you were facing EWE!! Regards Donal -- |
Jeff,
If CF has an effect on the Tides, And this is a question) why isn't the bulge on the far side of the earth, opposite the Moon in a single bulge? Again a question, what makes the Liquid (Tide) stop at edges of the globe and not continue to the off side of the globe? Why isn't it a simple matter of Liquid Displacement due to the greater amount of Liquid gathered for the High Tide under the Moon? These are simple Layman's questions, that to me seem logical. Ole Thom |
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