[Curiosity File]

According to a legend firmly established, Thales of Milet (VIth century before J.-C.) would be released very early from the belief in the divine causality of eclipses. In fact, according to the Greek historian Herodotus (about 484-425 BC), Thales had predicted to the Ionians an obscuration of the the Sun "for the year in which it occurred" (Survey I 74). Few authors, both ancient and modern, have questioned that which was held for one of the seven sages, has been able to predict a solar eclipse. According to Pseudo Plutarch (Opinion of philosophers, II 24), Thales understood the nature of the phenomenon ("the solar eclipse occurs when the Moon, whose nature is terrestrial, is placed just under him".) But this would obviously be not enough to move to the infinitely more complex step of the prediction of an eclipse occurring on a specific date and visible in a specified region of the globe. Some historians determined as sure that May 28, 585 BC was the date of the solar eclipse announced by Thales and the American historian O. Neugebauer said that there is no cycle to predict a solar eclipse in a given place, and that around 600 BC, and that the ephemerides compiled by the Babylonians and used by Thales did not contain any theory for predicting eclipses of the Sun. This legend of Thales is as unreliable as the one of Anaxagoras (500-428 BC) who "thanks to his knowledge of astronomical science" (Pliny the Elder, Natural History, II, 149), would have predicted a meteorite fall!

Point out "Thales" $ "Saros" are name for the same things.
 

https://promenade.imcce.fr/en/pages4/468.html

[edby]

This page explains how Halley (who financed Newton’s principia) rediscovered the Saros cycle

The eclipse paths he predicted were shifted with respect to the historical records. Halley identified the increasing length of the day as the reason for this, but it took 300 years to explain why the day was increasing in length.

The ocean tides are casued by the gravitational pull of the Moon and, to a lesser extent, the Sun. But as the tides are attracted to the Moon, the oceans appear to rise and fall while Earth rotates beneath them. This tidal friction gradually transfers angular momentum from Earth to the Moon. Earth loses energy and slows down while the Moon gains the energy and consequently its orbital period and distance from Earth increase.

The key point is how Halley was able to predict eclipse paths that differed from the tables. It follows he cannot have been using the tables themselves, or there would have been no difference.

[Rounder]

NASA is describing that they are predicting the eclipses based on the ancient Saros Cycle as used by the Ancient Babylonians.

No, they are not claiming to use the Saros Cycle to predict eclipses.  They talk about how the geometry of the earth-moon-sun system creates the cycle, but not how to use the cycle to predict eclipses.  For example, they say that a cycle moves from partial eclipses to total eclipses "after ten or eleven Saros cycles..." Well, which is it this Saros, ten or eleven?  How would you know?  In fact, if you look on another of their pages you find the situation is more unpredictable than that: "the number of partial eclipses in the initial phase ranges from 6 to 25" with no guidance on how to know from past cycles how many might be in future cycles.  The futility of using the Saros cycle for prediction is made fully evident when they sum it all up: "...the exact duration and number of eclipses in a complete Saros is not constant. A series may last 1226 to 1550 years and is comprised of 69 to 87 eclipses, of which about 40 to 60 are central"  That's no kind of basis for prediction!

Everything in astronomy is predicted on basis of patterns.

No, it is not.  Patterns are a starting point.  Understanding the reason for the patterns and (just as important) the deviations from those patterns yields better tools for prediction.  For example, each Saros cycle has a different number of eclipses in it, and a different number of partial, annular, hybrid (sometimes zero), and total (sometimes zero) eclipses.  How can that form the basis for prediction?  The interval between eclipses in the same Saros is eight years, eleven days, and approximately eight hours.  APPROXIMATELY.  How can THAT form the basis for prediction?  The answer is that it cannot, and it does not.  The Saros Cycle is a way to categorize eclipses.  To predict them you need to know the underlying physical movements, not just look up dates in a chart and project forward from them.

[edby]

To resolve this I wrote to Fred Espenak (website).
I asked

I occasionally contribute to a Flat Earth website with the aim of correcting scientific misconceptions and misrepresentations.  One of the claims made by Flatearthers is that space science, eclipses etc is entirely based on patterns and tables such as Saros, and Newton’s theory of gravitation does not enter into it at all. The 3 body problem is frequently cited as a reason why science and gravitation cannot predict eclipses. Is this true?

Of course he used to work for NASA, which will disqualify his opinion for some, but here is what he wrote, together with permission to publish here in his name.

Ed -

In a word “rubbish!”

Modern eclipse predictions do NOT use the Saros.

Rather, they are based on the orbital mechanics of the Earth, Moon, and Sun as laid out by Newton’s theory of gravitation.

More specifically, I use the Jet Propulsion Laboratory Developmental Ephemeris 430 (i.e., JPL DE430) to calculate the positions of the Moon, and Sun with respect to Earth. This is the raw material from which the Besselian elements used in eclipse predictions are derived from (https://en.wikipedia.org/wiki/Besselian_elements). It involves a lot of spherical geometry to calculate every conceivable aspect of any solar eclipse.

Using this method, I can calculate the time of the start and end of any solar eclipse to a fraction of a second for any location on Earth. I challenge any flat Earther to match that precision and accuracy using flat Earth geometry.

Best regards,

Fred Espenak

PS - By the way, the JPL DE is also used to help navigate all the interplanetary spacecraft into orbits or flybys of the planets (e.g., New Horizons and Pluto).

[AATW]

Of course he used to work for NASA, which will disqualify his opinion for some

Probably, although that would be an odd response from Tom when he is the one claiming NASA do use these cycles and linking to various NASA pages and willfully misunderstanding them to pretend they say what he claims they say.

This should really be the end of the matter, but I doubt it will be from past experience.

[Tom Bishop]

Tell Fred that response is nonsense. Read up on the Jet Propulsion Laboratory Development Ephemeris here: https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris

Read that page. Note that it is based on perturbations.

Recall that Celestial Mechanics professor Charles Lane Poor told us that perterbations = epicycles, and that epicycles = a way to find patterns from the ideal state.

The fact that it is based on perturbations shows that claims that it is based on a model founded on modern theories to be nonsense. It simply doesn't matter if some are calling the perterbations "relativistic corrections" or a "solution to the n-body problem". Perturbations are epicycles -- they provide corrections from the ideal state. They correct the wild and erratic movemnts of the planets to something ideal and predictable. These systems are using the same type of methods that were used to predict patterns in the sky developed hundreds of years ago!

[Curious Squirrel]

Tell Fred that response is nonsense. Read up on the Jet Propulsion Laboratory Development Ephemeris here: https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris

Read that page. Note that it is based on perturbations.

Recall that Charles Lane Poor told us that perterbations = epicycles, and that epicycles = a way to find patterns from the ideal state.

The fact that it is based on perturbations shows that claims that it is based on a model founded on modern theories to be nonsense. It simply doesn't matter if some are calling the perterbations "relativistic corrections" or a "solution to the n-body problem". Perterbations are epicycles -- they provide corrections from the ideal state. They correct the wild and erratic movemnts of the planets to something ideal and predictable. These systems are using the same pattern-based methods that were used hundreds of years ago!

Where do you get your definition of perturbation from Tom? It doesn't appear to match the definition given by the link in the wikipedia article at all. In fact cycles/epicycles aren't mentioned at all in the article. You appear to be slapping definitions on, and otherwise sticking your fingers in your ears (figuratively) and claim what's written in the articles is a lie. So where are you getting your definitions and information from? As I was unaware you were an expert in the field of Astronomy to be crying false at the statements of said experts. You've now point blank called Fred Espenak a liar. So I'm curious where you get your information from to say that.

[Bobby Shafto]

Read up on the Jet Propulsion Laboratory Development Ephemeris here: https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris

Read that page. Note that it is based on perturbations.

I can't find that in the page you linked.

I did find: "Each ephemeris was produced by numerical integration of the equations of motion, starting from a set of initial conditions." And perturbations are applied.

But not "based on perturbations."  Rather, based on equations of motion.

Nowhere does it say its based on "ancient"  cycles.

Bet the "ancients" could never have predicted the 2003 solar eclipse (Saros 152) that was visible over Antarctica.

[Tom Bishop]

Where do you get your definition of perturbation from Tom? It doesn't appear to match the definition given by the link in the wikipedia article at all. In fact cycles/epicycles aren't mentioned at all in the article. You appear to be slapping definitions on, and otherwise sticking your fingers in your ears (figuratively) and claim what's written in the articles is a lie. So where are you getting your definitions and information from? As I was unaware you were an expert in the field of Astronomy to be crying false at the statements of said experts. You've now point blank called Fred Espenak a liar. So I'm curious where you get your information from to say that.

I've posted this wiki link numerous times already, and Bobby has as well: https://wiki.tfes.org/Astronomical_Prediction_Based_on_Patterns#Perturbations

Perturbations
Description and Function

Gravitation Vs. Relativity
by Charles Lane Poor, PhD
Full Text Link

Motion of the Planets p.132

  “ The deviations from the “ideal” in the elements of a planet’s orbit are called “perturbations” or “variations”.... In calculating the perturbations, the mathematician is forced to adopt the old device of Hipparchus, the discredited and discarded epicycle. It is true that the name, epicycle, is no longer used, and that one may hunt in vain through astronomical text-books for the slightest hint of the present day use of this device, which in the popular mind is connected with absurd and fantastic theories. The physicist and the mathematician now speak of harmonic motion, of Fourier’s series, of the development of a function into a series of sines and cosines. The name has been changed, but the essentials of the device remain. And the essential, the fundamental point of the device, under whatever name it may be concealed, is the representation of an irregular motion as the combination of a number of simple, uniform circular motions. ”

Motion of the Planets p.138

  “ The Tide Predicting Machine of the Coast and Geodetic Survey at Washington is a note-worthy example of the application of the mechanical method [of prediction via epicycles]. The rise and fall of the tide at any port is a periodic phenomenon, and it may, therefore, be analyzed, or separated into a number of simple harmonic, or circular components. Each component tide will be simple, will have a definite period and a constant amplitude; and each such component may be represented mechanically by the arm of a crank, the length of which represents the amplitude; each crank arm being, in fact, the radius of one of the circles in our diagram.

Such a machine was invented by Sir William Thomson and was put in operation many years ago. The machine at present in use at Washington was designed by William Ferrel. It provides for nineteen components and directly gives the times and heights of high and low waters. In order to predict the tides for a given place and year, it is necessary to adjust the lengths of the crank arms, so that each shall be the same proportion of the known height of the corresponding partial tide, and to adjust the periods of their revolutions proportionally to the actual periods. Each arm must also be set at the proper angle to represent the phase of the component at the beginning of the year. When all these adjustments have been made, the machine is started and it takes only a few hours to run off the tides for a year, or for several years. This machine probably represents the highest possible development of the graphical or mechanical method. It is a concrete, definite mechanical adaptation of the epicyclic theory of Hipparchus.

But, because the Coast Survey represents and predicts the movements of tidal waters by a complicated mass of revolving cranks and moving chains, does any one imagine for a moment that the actual waters are made up of such a system of cranks? No more did Hipparchus believe that the bodies of the solar system were actually attached to the radial arms of his epicycles; his was a mere mathematical, or graphical device for representing irregular, complicated motions.

While the graphical, or mechanical method is limited to a few terms, the trigonometrical, or analytical method is unlimited. It is possible to pile epicycle upon epicycle, the number being limited only by the patience of the mathematician and computer. ”

Celestial Mechanics professor Charles Lane Poor lays out perturbations quite clearly. Perturbations = Epicycles, and Epicycles = a mathematical way to derive patterns from an ideal state, as exemplified by the tide predicting machine which predicts the tides.

[Tom Bishop]

Read up on the Jet Propulsion Laboratory Development Ephemeris here: https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris

Read that page. Note that it is based on perturbations.

I can't find that in the page you linked.

I did find: "Each ephemeris was produced by numerical integration of the equations of motion, starting from a set of initial conditions." And perturbations are applied.

But not "based on perturbations."  Rather, based on equations of motion.

Do a search on that page, Bobby. Perturbations are mentioned numerous times. It simply doesn't matter if anyone calls them as something which "accounts for the equations of motion" or that they are "corrections for gravity/relativity/etc," or that they "provide a solution to the n-body problem."

The method of perturbations is a pattern-predicting method, as explained by Celestial Mechanics professor Charles Lane Poor.

Nowhere does it say its based on "ancient"  cycles.

Charles Lane Poor tells us that they are epicycles, and there are other mentions of epicycles used in the VSOP section of the "Astronomy is Based on Patterns" page you linked in the OP.

[Bobby Shafto]

Celestial Mechanics professor Charles Lane Poor lays out perturbations quite clearly. Perturbations = Epicycles, and Epicycles = a mathematical way to derive patterns from an ideal state, as exemplified by the tide predicting machine which predicts the tides.

Thus spake Dr. Poor. Understandable that you've latched onto his 1922 work because it endorses a conclusion for which you are arguing. But if you're arguing from authority, as if citing a "celestial mechanics professor" is supposed to shut down criticism of your wiki page, you must know his was a cynical, critical and minority view.

He also contested General Relativity, which has since survived many challenges.

Just because you found one person who said (in 1922) what you want to believe is true, doesn't make it true. What do others say? You can't close your mind off once you find a passage that supports your preferred view. 

[Bobby Shafto]

Do a search on that page, Bobby. Perturbations are mentioned numerous times.

Mentioned, yes. "Based on..." no.

Charles Lane Poor tells us...

Others tell us otherwise.

[Curious Squirrel]

Consider as well: It's also possible for Dr Lane to be using a differing definition for his own work, just as TFES uses a different definition of 'perspective' than is mainstream. The article on JPL specifically hyperlinks to another article on perturbations, that explains what they are. Why would you look to use an older definition from someone else? The one you are constantly attempting to use doesn't appear to agree with current definitions, and I would argue you only wish to force it forward because it supports your PoV.

[edby]

https://en.wikipedia.org/wiki/Charles_Lane_Poor
Charles Lane Poor (January 18, 1866 – September 27, 1951) was an American astronomy professor, noted for his opposition to Einstein's theory of relativity.

Essentially a Victorian scientist. Do you have any more recent sources?

[RonJ]

It looks like there is confusion in the word 'perturbations'.  Charles Lane Poor seemed to use that word in one context and the modern-day scientists seem to be using the same word to describe something altogether different.  In any event, the modern-day folks take the bodies and put them into an initial condition.  Then all the Newtonian laws are applied with a computer program.  Perturbations are then the difference between what the first approximation to the predicted motion and the actual observed motion happens to be.  The first approximation is the result of the classic 3 body problem based upon the nominal condition of all the bodies.  After the results of the first approximation are in then the program is amended to adjust the orbits for the perturbations (differences) due to all smaller effects on the orbital bodies.  In each case the model is adjusted using the standard Newtonian laws of motion to calculate the ever-smaller adjustments needed.  The whole process is a mixture of the old and the new.  Newtonian laws of motion are the underlying theme to everything and the modern computers are just a means to accomplish all the calculations. At heart of everything is the mathematics that was needed to fine tune the Newtonian laws to choreograph everything. 
At no time are any historical data used in any of these calculations.  All the orbital data is newly calculated with the computer program.

[RonJ]

More modern sources aren't really needed, just more accurate ones.  Look at the works of Nathaniel Bowditch and Issac Newton for a better idea of how things actually work in the real world.  Observe and compare those observations to what the theory says.  If there's a difference adjust accordingly.  When one theory had a plethora of problems it usually is better to consider something else.  Apply Occam's razor, that usually is best. 

[Tom Bishop]

https://en.wikipedia.org/wiki/Perturbation_(astronomy)

Most systems that involve multiple gravitational attractions present one primary body which is dominant in its effects (for example, a star, in the case of the star and its planet, or a planet, in the case of the planet and its satellite). The gravitational effects of the other bodies can be treated as perturbations of the hypothetical unperturbed motion of the planet or satellite around its primary body.

They state that the 'gravitational effects' are being treated on basis of "perturbations".

Further down, we read about Special Perturbations:

In methods of special perturbations, numerical datasets, representing values for the positions, velocities and accelerative forces on the bodies of interest, are made the basis of numerical integration of the differential equations of motion.[6] In effect, the positions and velocities are perturbed directly, and no attempt is made to calculate the curves of the orbits or the orbital elements.[2] Special perturbations can be applied to any problem in celestial mechanics, as it is not limited to cases where the perturbing forces are small.[4] Once applied only to comets and minor planets, special perturbation methods are now the basis of the most accurate machine-generated planetary ephemerides of the great astronomical almanacs.[2][7]

From Perturbations in Complex Molecular Systems we read the following:

  “ In general perturbation methods starts with a known exact solution of a problem and add “small” variation terms in order to approach to a solution for a related problem without known exact solution. Perturbation theory has been widely used in almost all areas of science. Bhor's quantum model, Heisenberg's matrix mechanincs, Feyman diagrams, and Poincare's chaos model or “butterfly effect” in complex systems are examples of perturbation theories. ”

It's just a way to find patterns from the ideal state. It is a method that is used in many areas of science. Perturbation methods have nothing to do with any modern theory of astronomy.

Recall that Charles Lane Poor said that planetary perturbations are calculated on basis of Fourier series.

In the below paper by the Smithsonian Astrophysical Observatory we see that planetary perturbations are being calculated on basis of Fourier series:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690030023.pdf

The analytical procedure for computing second-order perturbations in
rectangular coordinates, according to Brouwer's theory of planetary motion,
is given. Single- and double-harmonic analyses and the multiplication of
Fourier series with numerical coefficients are used in the computations. In
the series multiplication, a variable tolerance is considered, enabling us to
avoid the difficulties arising from a small divisor.

Looks like Charles Lane Poor was, and still is, correct.

Fourier Series = Data Analysis/Fourier Analysis = Finding Patterns

https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.1944

Further, Fourier series have been used to quantify a variety of complex periodic patterns in ecology

https://www.tandfonline.com/doi/abs/10.1080/713819066?journalCode=tmop19

When two or more patterns, each exhibiting some form of periodicity, overlap there usually result distinct moiré fringes. If the periodicities in the original patterns are represented by Fourier series, the shape and harmonic structure of the moiré fringes can be predicted

All of it is just data and pattern analysis.

"The terms and definitions changed! Now it means that the planets are calculated entirely based on Newton and Einstein's laws..." Sure sure...

[edby]

If you look further down, Tom, you will clearly see how these equations mathematically solve for Newtonian forces.

It's not 'just patterns'.

[Tom Bishop]

If you look further down, Tom, you will clearly see how these equations mathematically solve for Newtonian forces.

It's not 'just patterns'.

That's just fluff. As soon as they start using perturbation methods, Fourier series, harmonic motion, data and statistical analysis to compute the position of the planets it totally nullifies the underlying theory.

[Bobby Shafto]

If you look further down, Tom, you will clearly see how these equations mathematically solve for Newtonian forces.

It's not 'just patterns'.

That's just fluff. As soon as they start using perturbation methods, Fourier series, data and statistical analysis to compute the position of planet it totally nullifies the underlying theory.

Huh?

Perturbations are deviations. They aren't stand-alone.

Deviations from what?