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Topic: The Tides ... Take 5 (Read 1631 times) previous topic - next topic

F X, cold one and 2 Guests are viewing this topic.
  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #50
There's a slim volume by fizyxcyst George Gamow titled 'Gravity' which is a good intro to that subject for the lay reader, written in Gamow's signature clear and accessible style.  In one section he deals specifically with how the Moon raises ocean tides on Earth.


https://archive.org/stream/Gravity_857/Gamow-Gravity_djvu.txt
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

Re: The Tides ... Take 5
Reply #51
There's a slim volume by fizyxcyst George Gamow titled 'Gravity' which is a good intro to that subject for the lay reader, written in Gamow's signature clear and accessible style.  In one section he deals specifically with how the Moon raises ocean tides on Earth.


https://archive.org/stream/Gravity_857/Gamow-Gravity_djvu.txt


"Many people who hear for the first time this explanation of ocean tides find it hard to understand why there are two tidal waves, one on the side turned toward the Moon or the Sun, and another on the opposite side where ocean waters seem to move in the direc-
tion opposite to the gravitational pull."

The physics in all this is very clear.  The question is, what's the FysiX? 

Out of curiosity, what would the laws of fysix predict if a moon were stationary above some point on an otherwise unperturbed, ocean-covered planet (i.e. the moon was in a geostationary orbit)?  Would fysix allow for two (stationary) bulges in that case?

Are you going to answer this, F X?

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #52
https://archive.org/stream/Gravity_857/Gamow-Gravity_djvu.txt

"Many people who hear for the first time this explanation of ocean tides find it hard to understand why there are two tidal waves, one on the side turned toward the Moon or the Sun, and another on the opposite side where ocean waters seem to move in the direction opposite to the gravitational pull."
[/quote] That's just another example of the irony of it all.  There does not exist, nor can there exist. two distinct tidal waves/bulges.   Instead we see the amphidromic systems (and related very complex other waves), pumped by the gravity differential, but in  no way is there twin bulges following the moon.

http://volkov.oce.orst.edu/tides/

In reality,much of the tidal waves are actually moving the other way from the theoretical "following the moon". Nature is often far different than the mental constructs we imagine it is.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #53
Out of curiosity, what would the laws of fysix predict if a moon were stationary above some point on an otherwise unperturbed, ocean-covered planet (i.e. the moon was in a geostationary orbit)?  Would fysix allow for two (stationary) bulges in that case?

Are you going to answer this, F X?
I ignore nonsense questions.  Unless there is some humor in humoring the questioner.  Experience has shown you have no sense of humor about any of it.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

Re: The Tides ... Take 5
Reply #54
Out of curiosity, what would the laws of fysix predict if a moon were stationary above some point on an otherwise unperturbed, ocean-covered planet (i.e. the moon was in a geostationary orbit)?  Would fysix allow for two (stationary) bulges in that case?

Are you going to answer this, F X?
I am a troll.

right

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #55
If you want an answer to a physics question, you have to supply enough info to be able to calculate shit out.   An object small enough to remain in geostationary orbit (which is an artificial orbit, no natural satellite/moon could remain there) would have no tidal effect at all.

"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • MikeB
Re: The Tides ... Take 5
Reply #56
As far as I can tell, an object need not be "small" to be in geostationary orbit, nor is there any reason such object, natural or man-made, could not remain there for human lifespan timeframes.

Clearly, a "large" object with significant fraction of earth mass, orbiting at that distance, about 1/10 distance to the moon, would cause a mutual earth - object orbit about a barycenter somewhere in space between the two.  The earth-moon barycenter is 3/4 of the way out from the center of the earth toward the earth's surface.  The earth-moon mutual orbit around this barycenter is what contributes to the tendency of a tidal bulge to form on the side of the earth facing away from the moon.

Re: The Tides ... Take 5
Reply #57
If you want an answer to a physics question, you have to supply enough info to be able to calculate shit out.   An object small enough to remain in geostationary orbit (which is an artificial orbit, no natural satellite/moon could remain there) would have no tidal effect at all.

That might be true in FysiX, but it ain't the case for physics. 

Re: The Tides ... Take 5
Reply #58
As far as I can tell, an object need not be "small" to be in geostationary orbit, nor is there any reason such object, natural or man-made, could not remain there for human lifespan timeframes.

Correct.

Quote
Clearly, a "large" object with significant fraction of earth mass, orbiting at that distance, about 1/10 distance to the moon, would cause a mutual earth - object orbit about a barycenter somewhere in space between the two.  The earth-moon barycenter is 3/4 of the way out from the center of the earth toward the earth's surface.  The earth-moon mutual orbit around this barycenter is what contributes to the tendency of a tidal bulge to form on the side of the earth facing away from the moon.

The barycenter would be much closer to the center of the earth in this case, since the earth/moon distance would be a lot smaller.

Re: The Tides ... Take 5
Reply #59
Out of curiosity, what would the laws of fysix predict if a moon were stationary above some point on an otherwise unperturbed, ocean-covered planet (i.e. the moon was in a geostationary orbit)?  Would fysix allow for two (stationary) bulges in that case?

If this was a water world, tidal forces would cause two bulges. This is because only the center of the earth is at the right orbital distance from the barycenter for the correct orbital speed.



Since the earth has a large diameter, the water on the far side of the earth from the moon is 4,671 km (distance from center to barycenter) + 6,378 km (earth radius) from the barycenter and is moving faster than the correct orbital speed, forcing that water mass outwards.

On the other hand. the water closest to the moon is moving too slow for the correct orbital speed and tends to fall towards the moon. So, two bulges.

To answer your question:

Since the earth and the moon are orbiting each other (about their barycenter), over time they will tend to synchronize their rotation and revolution speeds, always keeping the same hemisphere of the moon facing the earth and eventually the earth will do the same thing with respect to the moon. That is, they will become tidally locked with each other. When that happens, there will be no moon tides, only sun tides.

So the answer is No, unless you include sun tides.
Balloons will set you free!

Re: The Tides ... Take 5
Reply #60
Mayhap you're overthinking this one F X.  There is no reasonable doubt about the tidal driving force - as outlined by Gamow - but the World is a messy complicated place.  What we observe in your global oceanic tide plots is the resultant of those tidal forces on the variable depth oceans broken up by the irregular continental land masses.

Re: The Tides ... Take 5
Reply #61
Mayhap you're overthinking this one F X.  There is no reasonable doubt about the tidal driving force - as outlined by Gamow - but the World is a messy complicated place.  What we observe in your global oceanic tide plots is the resultant of those tidal forces on the variable depth oceans broken up by the irregular continental land masses.

That's exactly right.  The question I just asked has a totally obvious answer, as everyone here except F X knows. 

A slightly more interesting question is what happens on an ocean earth (with a uniform depth ocean, say of 5 km) and with the moon in its actual orbit.  An easier one is what happens to the water in a hypothetical equatorial canal  if the moon was in an equatorial orbit, but with its true orbital radius and everything else as it is.

The answer to both of those questions is two tidal bulges traveling at the same apparent speed as the moon in the sky (i.e. about 1000mph, determined mostly by the rotation of the earth). 

Since that speed exceeds the wave speed in an ocean of 5km depth, F X is convinced it violates the laws of FysiX. That may be, but it doesn't violate the laws of FysiX (in fact, it's a prediction of them).  F X actually managed to find a textbook that made that same incorrect assertion.  I communicated with the author and got it corrected for the latest edition. 

That's this years-long thread in a paragraph.

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #62
Mayhap you're overthinking this one F X.  There is no reasonable doubt about the tidal driving force - as outlined by Gamow - but the World is a messy complicated place.  What we observe in your global oceanic tide plots is the resultant of those tidal forces on the variable depth oceans broken up by the irregular continental land masses.
I don't spend much time on the matter.  In 1992 it might have been a contentious issue, for some people, with models and tide measurements and theory all still pointing to the amphidrome theory of tides, (the dynamic theory of Laplace), but as we can see, with an abundance of idiotic graphics and explanations still trying to teach that there are twin bulges, the matter is firmly entrenched in some minds, and they just can't make the leap.

But here's the bottom line.  After the TOPEX/Poseidon mission, we had accurate detailed data on the oceans, which allowed the scientific world to know what the ocean tides actually look like. With the Jason-1 and then the OSTM/Jason-2 satellites there was no doubt.  What's astounding is that Laplace figured it out in 1775, his theory described the ocean's real reaction to tidal forces, and took into account friction, resonance and natural periods of ocean basins.  His insights and thinking about the matter have been shown to be true, and Newton was wrong. (along with a really long list of other scientists)

This is actually explained (along with Newton's canal circling the earth, with no friction, and the sun and moon aligned over the equator) in the 11th edition of the Encyclopedia Brittanica, Volume 26, pages 938-961

If you think any of the craptastic arguments in this long suffering thread are of any value, reading the epic section on tides from 1910 would both amuse and educate you, in so many ways.  23 pages of everything tide related, including the history of the study and theories of tides.  And of course the canal.



"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #63
The answer to both of those questions is two tidal bulges traveling at the same apparent speed as the moon in the sky (i.e. about 1000mph, determined mostly by the rotation of the earth). 
That is almost exactly the centuries old scientific argument between the concepts of  Newton and Laplace (along with a shit ton of other interested scientist)

Laplace wrote an entire book about it.  The essential argument depends on no friction, and a sun and moon perfectly aligned over the canal, which has to be at the equator.  And a depth of the canal so that the wave has no friction with the floor of the canal.

We can now actually program that shit into a computer and see what would happen.
  • Last Edit: May 05, 2018, 12:02:11 PM by F X
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #64
Once you get of friction, almost anything is possible.

Even a supersonic wave with a wavelength of 12000 miles!
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • uncool
Re: The Tides ... Take 5
Reply #65
FX, it's been literal years. Are you seriously going to keep on bringing this up without once learning the actual basis of the discussion - wave theory?

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #66
According to the physics, if the worlds oceans were deep enough for the tide wave to move freely,  no continents and no spinning of the planet (just the moon orbiting), right over the equator,  the range of the tide would be 0.6 meters

Or in feet, the high tide would a foot above normal, the low ride a foot below.  But this would only be at the center of the bulge.  The farther from the equator you are, the less tidal range, with zero at the poles.

That's the influence of the moon.  In reality you have to add the solar influence, so it would vary with the lunar month.

At first and third quarter, it would be less. The theoretical bulge of the oceans would be hard to even measure at times, since wind can raise areas of the ocean by more than that.  And atmospheric pressure also would change the height of the ocean.

An island on the equator in this mythical ocean world would measure tides of a very small magnitude.  But the deformation of the solid earth itself would be greater than the ocean tides.  At new moon the solid earth tide is a meter.  But is there a lag in the deformation of the solid earth and the expected earth tide?  Measurements and calculations removing the ocean leading show a solid Earth tide phase lag of 0.38°

Schwiderski estimated a lag of 0.44°, using the measured deceleration of the Moon. But it seems this phase lag is actually from the deformed bottom of the ocean, from the ocean tides, which as we know are not twin bulges, but complex amphidromic systems, which have no uniform or synchronized deformation of the ocean bottom at all.

On our magical world the ocean loading would be in sync with the moon, so the ocean loading would be exactly over the earth tide, meaning some weird stuff would happen, both with the earth tide and lag, as well as the deceleration of the Moon from the tidal forces.

Or we could just look at what actually happens and realize nature doesn't give a shit what you think.





"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #67
the actual basis of the discussion
It started with spork making a false statement that the higher tides were caused by the water having to go around land masses.  In order to explain why that is wrong we had to explore all kinds of shit, but mostly in order to know why that was wrong,  you have to understand the amphidromic systems, and why there are no supersonic tide bulges following the moon.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #68
Everything else is just food for the lolcows
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • MikeB
Re: The Tides ... Take 5
Reply #69
the actual basis of the discussion
It started with spork making a false statement that the higher tides were caused by the water having to go around land masses.  In order to explain why that is wrong we had to explore all kinds of shit, but mostly in order to know why that was wrong,  you have to understand the amphidromic systems, and why there are no supersonic tide bulges following the moon.

Wait, are you saying that someone here at one time said that there is ocean water moving at supersonic speed with respect to the earth's surface?  I don't think I have seen that.

Re: The Tides ... Take 5
Reply #70
the actual basis of the discussion
It started with spork making a false statement that the higher tides were caused by the water having to go around land masses.  In order to explain why that is wrong we had to explore all kinds of shit, but mostly in order to know why that was wrong,  you have to understand the amphidromic systems, and why there are no supersonic tide bulges following the moon.

Wait, are you saying that someone here at one time said that there is ocean water moving at supersonic speed with respect to the earth's surface?  I don't think I have seen that.

On an ocean/canal earth, the wave would move around 1000 mph.  But none of the water itself moves at that speed - it just moves up and down (quite slowly, because the wave has very long wavelength).

If you think about people doing the wave in a sports stadium, the wave can (in principle) travel faster than light without violating any law of physics.  Obviously, none of the people are moving very fast. 

Re: The Tides ... Take 5
Reply #71
Once you get of friction, almost anything is possible.

Even a supersonic wave with a wavelength of 12000 miles!

I guess you meant to write, "Once you get rid of friction, almost anything is possible."  No one is getting rid of friction.  Also, it's not friction that determines or limits the shallow water free wave speed.  As usual, you don't have a clue about physics.

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #72
it's not friction that determines or limits the shallow water free wave speed.
OMG it's like you know nothing about waves at all

http://www.iupui.edu/~g115/mod11/lecture04.html

It's actually called bottom friction

You dumbass
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

Re: The Tides ... Take 5
Reply #73
it's not friction that determines or limits the shallow water free wave speed.
OMG it's like you know nothing about waves at all

http://www.iupui.edu/~g115/mod11/lecture04.html

It's actually called bottom friction

You dumbass


That link is wrong, or rather, using "friction" in an inexact sense.  But explaining this to you is as pointless as explaining it to a houseplant.

For anyone else reading, the speed of a water wave is normally computed ignoring friction, and the result (which scales as the square root of the water depth when the wavelength is longer than the depth) is exact in the approximation of uniform depth, no friction, etc.  Details are here for instance https://en.wikipedia.org/wiki/Dispersion_(water_waves).

  • F X
  • The one and only
Re: The Tides ... Take 5
Reply #74
bottom friction

That link is wrong, or rather, using "friction" in an inexact sense.

Bottom Friction
from Glossary of Meteorological Terms (2015)
by American Meteorological Society
The momentum transfer at the lower boundary of the ocean to the solid earth by friction at the ocean bottom

No wonder you seem so obtuse at times.  You are actually an idiot. 
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭