Sir George Howard Darwin, FRS (9 July 1845 – Cambridge, 7 December 1912) was an English astronomer and mathematician, the second son and fifth child of Charles and Emma Darwin. ... [a Cambridge man] ... He studied tidal forces involving the Sun, Moon, and Earth, and formulated the fission theory of Moon formation.
Was von der deutschen Wikipedia bestätigt wird:
Sir George Howard Darwin, F.R.S. (* 9. Juli 1845 in Down, Kent; † 7. Dezember 1912 in Cambridge, England) war ein britischer Astronom und Mathematiker. Er war das fünfte Kind (zweiter Sohn) von Charles Darwin. Er ist bekannt für seine Theorie, dass der Mond einst Teil der Erde gewesen sein soll (Abspaltungstheorie). ... [studierte und dozierte in Cambridge] ... Seit 1882 untersuchte Darwin den Effekt der Gezeiten auf das Sonnensystem mit mathematischen Methoden und wurde zu einem anerkannten Experten auf diesem Gebiet. Er veröffentlichte 1883 eine Arbeit über die Gezeiten in der Zeitschrift der British Association for the Advancement of Science, die es auch dem Laien möglich machte, die Gezeiten vorauszuberechnen. Weiterhin verfasste er entsprechende Artikel in der Encyclopedia Britannica und dem Admiralty Scientific Manual. Seinen Berechnungen folgend, postulierte er die Abspaltungstheorie zur Entstehung des Mondes, wodurch er große Bekanntheit erlangte, auch wenn sie heute als falsch betrachtet wird. Laut der Theorie rotierte die Erde in ihrer Frühphase so stark, dass sich durch Instabilitäten ein Teil ablöste und den Mond bildete. 1882 fügte der Geologe Osmond Fisher (1817−1914) die Feststellung hinzu, dass der Pazifische Ozean die heute noch sichtbare Narbe dieser Abspaltung darstellt.
Now, before I go on, why did I go to German wikipedia? Because, since anyone can reedit a wiki article, any time a wiki article can have false info. But it is very much less likely to have false info in two languages at once, since the content of the articles in different editions, like different languages is not mechanically interconnected.
I found three different takes on what Émile Combes had for doctorate in 1860: French article was confused and said medicine, but both English and German said he became a physician in 1867, then the English article said the 1860 doctorate was in Letters, and German - what concurs best with him having been a defrocked priest - that it was Theology. But let us get back to tidal theory of G. H. Darwin, shall we?
As you might know, St Robert Bellarmine was a judge at the trial of Galileo. He said one ought to be very cautious, and if Galileo could prove his theory, one would have to agree on his interpretation of the passage in the book of Joshua. That was so to speak his plan B. But first one would stick to patristics until point proven.
One of Galileo's "proofs" was a tidal theory that gave false predictions about tides. How would the judges know? One of them was from Portugal. He had seen how tides really are, and Galileo was wrong.
That is not the case so clearly with George H. Darwin's theory of tides. [Which is not the one I refer to here - see further parts of the series] It is still standard, unlike his theory of Moon being a spin off from Earth. And he formulated it or it was at his time received as a theory within the framework of heliocentrism.
Certainly it is grounded in Newton's theory of gravitation: attraction is proportional to mass of attracting body and inversely proportional to square of distance. Meaning both Sun and Moon attract water in Earth on the side they are. Let us check the case both Sun and Moon are on same side of Earth. Which is on any cosmology the case at New Moon. Let us check this in geocentric, then again heliocentric, and then some back and forth about it?
Before we go on: how come Newton did not think of it? Or did he, and did he reject it? Has Laplace some place in this debate?
Attraction from Sun and Moon added together does attract bodies the closer they are already.
Each of them attracts both water their side of the Earth more than the solid mass of Earth itself, and solid mass of Earth itself more than water at the other side.
a) Water is drawn to one side, so is solid mass of Earth, hence Earth is not stable (and that is the end of geocentrism?)
b) Solid mass of Earth is still, water on side of Sun and Moon is drawn sunwards, water on other side is not drawn to that other side, rather flowing along earth's side towards the Sun and Moon side - which contradicts the behaviour of tides, and is therefore untrue.
OK, but does Heliocentrism fare any better?
Earth with water around it are in orbit. Water on in-orbit side is drawn inwards relative to orbit, into Sun and to the Moon which is in-orbit. Earth too is drawn in-orbit, but less, and out-orbit side water is drawn still less in-orbit.
And, since Moon is in-orbit and adds its attraction to Sun, all is drawn in-orbit and falls very presently into the Sun, right?
Oops, that makes a very quick end of Earth's place in Solar system! First New Moon, Earth is drawn in-orbit into Sun, breaking equilibrium, and Earth disappears forver, before there is another New Moon? No.
No, the "orbit of Earth" is really the orbit of not Earth solid mass alone, but: solid mass, waters all sides, atmosphere and Moon, and that according to common point of gravity.
Why is geocentric not allowed similar advantage?
a) Because he did not think of it?
But the point of the point of equilibrium the point of gravity, does not depend on heliocentric astrophysics!
b) Because it is not applicable?
But what if it is? Cf. point i) a) above, in case that movement of Earth is by such gravitational nudges is not incompatible with geocentrism. Or ask Robert Sungenis about it. He is a great proponent for joining Tychonian Geocentrism with Newtonian Astrophysics.
Is this equilibrium round gravity point really applicable even to heliocentrism?
If this is applied to heliocentrism there is a difficulty:
a) in its consequences: if any point on earth is simultaneously subject to 3 movements, how come we do not feel it any more, rather less than being subject to one uniform movement in a very fast train or plane?
The three movements are of course:
- yearly orbital movement which goes speeds up and slows down
- daily rotational movement
added to both there is then:
- monthly wobbling movement
And we feel nothing of it?
b) in its very mechanism: is there any example on earth of something held together purely by gravitational forces despite disparity of pieces, especially despite big discontinuity as between Earth and Moon, and yet sharing one common point of gravity?
Is it the only explanation possible?
What if angels were acting out a command equivalent to align="center" on the waters around Earth?
a) it would take away any difficulty with Geocentrism
b) as also with Heliocentrism
c) which means it does not decide between them, it is excluded as a proof between them as which of them is right, but acceptable as an explanation, whichever of them be right, how it really works.
Now it is funny, that George H. Darwin should make a theory, even if it correctly explains all the facts, which Newton had the possibility to make but did not make, is it not?
I mean Isaac Newton also taught that gravitation increases according to mass of whatever body be pulling and decreases according to sqaure of the distance. That is exactly where G. H. D. got his main explaining principle from. Did he have a reason to shut up about tidal theory applications? Was it just caution about Galileo's failed tidal theory, or some other caution too?
Here is how he reasoned about orbit of Earth, and by extention of any orbit of any planet, and without taking heed to include in explanation how this interacts with gravitation from other planets whose orbits pass by closer or less close and sometimes more than one at once:
a) Earth is always falling into the Sun, and always missing it. Falling, because gravitation of Sun induces acceleration inward, missing, because previous angle of movement is always interfering with that fall, and also being interfered with. Together this amounts to a series of take-offs inward that amount to one - circle? no elliptic orbit.
b) Could this equilibrium be disturbed? According to Newton in such a case God would set the equilibrium right again. As long as it takes, up to judgement day.
So, at Newton's stage of thought, atheism was a technical impossibility. There was in Solar System no inherent guarantee the equilibrium would never yield to a real spin-off out of Solar System or a real fall into the Sun. Laplace tried to find such a thing, maybe since unwilling to acknowledge a Creator, like this somewhat:
Originally Solar System was a cloud of gas, spinning in vortical movement aroud itself, faster and faster until Sun was made by big pressure and big heat into a process of nuclear fusion. Parts of original cloud outside Sun began to form planets, and planets though no longer are parts of a uniformly vortical gas cloud, they still stay in the places they occupied in it and remain at same speed which guarantees the orbits staying in place.
This is a very clear reasoning and a very convincing explanation, I presume, since I have heard other varieties, like:
This is a very clear reasoning and a very convincing explanation, I presume, since I have heard other varieties, like:
All of gas cloud went into the making of the Sun and then another one passed by, and its gravitation drew a long and big cigar of mass out of it,
in which cigar Jupiter is about centre and the extremes are Mercury near Sun and Pluto near edge of Solar System, Earth being at a point between Mercury and Jupiter
and then the cigar went on forming hot balls of gas, just not hot enough to be the Sun and these stayed in orbit around the Sun and stayed in their places ... and do so up to know, nearly 10 billions of years later.
When I was about 8 years old, things like these used to amaze me and amuse me, not to say bemuse me. Oh, wow! How clever to reason that one out! At 9 I was a Christian, and had another explanation. I am not very tempted to go back to diverse variants of the Laplace theory, and I am not very sure about Newton's theory of planetary orbits either.
But is there any particular reason to be sceptic about Newton or Laplace?
I mean, with God and angels, there is another explanation available. But are Newton and Laplace off the hook?
Newton's orbital theory is not tested on Earth, s far as I know. A stone on a piece of string is not a model even simplified of an orbit kept going in circles by opposing forces of speed drawing outwards and string drawing inwards with a "point of equilibrium" moving around the orbit. Since, the string is not an equal but opposing force, but a force holding the stone in by being stronger than outward pull: if it were weaker it would burst, if it were equal it would be on bursting edge, I suppose.
And Laplace has a weakness he shares with ... Sir George H. Darwin:
No independent evidence shows that either a consolidation of gas would stay in same orbit as original vortical gas clouds (or for that matter that gas would start a vortical movement without there being an outlet or an exterior cause of motion, as a water vortex is above a subterranean outlet and air vortices are caused by rotation of Earth East-ward OR Universe West-Ward) or that Earth solids, water, atmosphere and Moon would stay along with them around a common point of gravity. Theory says so. On its own. Only confirmation: the phenomena they say they explain.
PS: Oh, I found another aspect hereto:
Since tide is only a few metres (10 at utmost or something?) it makes no difference for earth orbit according to heliocentric model.
Neither, of course, and for same reason, does it invalidate the geocentric model: Sir George H. Darwin's tidal theory remains feasible for both. Which does not mean it is proven. It is only one theory, along with angelic one, and these not mutually exclusive, which are possibgle in accordance with known facts about tides.