Friday, November 6, 2015

How tides really work, and why the old "two bulge" idea isn't real (90 links and 10 animations/movies) - last update Dec 7 2023

There is no tidal bulge.  There is no bulge on the opposite of the world either.

Below you may find sources, references and animations to understand how the ocean tides actually occur, (a futile attempt to rid the scientific world of the folly of the twin bulges theory/explanation for the ocean tides).  Physics stack page explaining why no bulges, good start for scientific minds

There is no evidence, none, that two bulges follow the moon, creating the ocean tides. This blog post is an extensive entry that does not appear on Wikipedia.  The following does appear on Wikipedia, and I wrote it many years ago.

Dynamic theory of the ocean tides

While Newton explained the tides by describing the tide-generating forces and Daniel Bernoulli gave a description of the static reaction of the waters on Earth to the tidal potential, the dynamic theory of tides, developed by Pierre-Simon Laplace in 1775,[31] describes the ocean's real reaction to tidal forces.[32] Laplace's theory of ocean tides takes into account frictionresonance and natural periods of ocean basins. It predicts the large amphidromic systems in the world's ocean basins and explains the oceanic tides that are actually observed.[33]

The animation below shows the amphidromic systems that actually exist.  There are no twin bulges.  Nor can there ever be.  Multiple other movies and animations show a more precise view of this. These giant circular waves are Kelvin waves.

Instead there are amhphidromic systems, illustrated below.  Amphidromes!  Amphidromes and standing waves! Amphidromic systems! (something not found on Wikipedia)

(original animation by Dutch, I added the moving bars.  The original animation is no longer online)


online version 

GGravity alone  does not explain the tides.  And that article is wrong about the tides. 

Wrong and not wrong in the same explaining (why there are no tides in your coffee)

Seafriends page, excellent explaining, explains the dynamic theory 

(note:This blog entry also contains links to atmospheric tides and earth tides, which it turns out includes amospheric amphidromes)

Latest animation showing the global tides in a sweet 3D view.
Note that the commentator makes the error of claiming the continents are the only reason for the lack of twin bulges.  (this is a basic science error)



This entire blog is an expansion of the 2011 blog post,  How the oceanic tides actually work.  

How the real tides on earth behave.  A bad case of SIROTI

Tides are shallow water waves, a shallow-water wave  speed is controlled by depth of ocean


Tide waves are forced waves at most latitudes because the tide-generating forces move faster than the speed of a shallow water wave of the tide wave wavelength. The tide lag is at a maximum at the equator and is reduced at higher latitudes.Chapter 10 tides (dead link, use archive.org)


College lecture on the Dynamic Theory explains amphidromes (and much more) but boring



NASA TOPEX from 2000



Video of a Very cool model of the actual tides


M2 Tide animation



Global amphidromes and tidal ranges (flash, no longer works)








Videos of tide animations
NASA TOPEX from 2000

PBS video why everyone is wrong (which is also wrong)

Below, Land tide example, one month's changes in Kansas USA






The Tidal and Other Problems Google Books



All the wrong things about the moon and tides


Global animation page 

Polar region animation (huge GIF file)

A new theory of the tides

By John Debenham

- For fun, here is an old book with a conflict over tide theory in it.

(arguments over the tides are very old) Recall the old saying, “the tomb of human curiosity”

A correction to the quote from Arago, which is not correct. For example, from this page

"French astronomer François Arago once said that studying the tides was the tomb of human curiosity."

No, he did not.  Here's the actual text, from Bartleby

 If we descend from the heavens to the earth, the discoveries of Laplace will appear not less worthy of his genius. He reduced the phenomena of the tides, which an ancient philosopher termed in despair “the tomb of human curiosity,” to an analytical theory in which the physical conditions of the question figure for the first time. 
Francois Arago (1786-1853), physicist, astronomer.

End note - like almost all my blog post, this is like a Wikipedia page, but nobody can delete data and information on this page.  Rather than deal with the futility of dealing with idiots, I just add info to the blog pages when I come across it.

And yes, somebody did delete the article on The Dynamic Theory of Tides from Wikipedia.


Update November 2022 -->








The internet has a lot of official pages that are simply wrong

Like the following


Gravity, Inertia, and the Two Bulges

The gravitational attraction between the Earth and the moon is strongest on the side of the Earth that happens to be facing the moon, simply because it is closer. This attraction causes the water on this “near side” of Earth to be pulled toward the moon. As gravitational force acts to draw the water closer to the moon, inertia attempts to keep the water in place. But the gravitational force exceeds it and the water is pulled toward the moon, causing a “bulge” of water on the near side toward the moon (Ross, D.A., 1995).

On the opposite side of the Earth, or the “far side,” the gravitational attraction of the moon is less because it is farther away. Here, inertia exceeds the gravitational force, and the water tries to keep going in a straight line, moving away from the Earth, also forming a bulge (Ross, D.A., 1995).

This one is wrong as well

High tides and low tides are caused by the moon. The moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.

That's just true, it does not explain how the ocean tides behave.


This video

https://www.youtube.com/watch?v=bPhhYhN0FAc&t=783s

Is also wrong.  The water of the oceans does not collect in some giant bulge and follow the moon.  It's not even close to that.










 



3 comments:

  1. The ebb and flow is the result of the rotation of the Earth and the gyres. https://www.wxforum.net/index.php?topic=35094.0

    ReplyDelete