Talk:Paul Wittich

Record of Logicus edit of 27 January 2008

This is to provide a record of edits that provide an easy reference for comparison with any future amendements:

"Paul Wittich (1546—1586) was a Silesian mathematician and astronomer[1] whose Capellan geoheliocentric model, in which the inner planets orbit the sun but the outer planets orbit the Earth, may have directly inspired Tycho Brahe's more radical geoheliocentric model in which all the 5 known primary planets orbited the Sun which in turn orbited the stationary Earth.[2]

It is evident from Wittich's diagram of his Capellan system that the Martian orbit does not intersect the solar orbit nor those of Mercury and Venus [3], and would thus be compatible with solid celestial orbs, with the Solar orb containing the orbs of Venus and of Mercury and itself in turn wholly circumscribed by a Martian orb. This was in significant contrast with Ursus's geoheliocentric model in which the orbits of Mercury and Venus intersect the Martian orbit but the Solar orbit does not [4], and also with the Tychonic model in which the Martian orbit also intersects the Solar orbit in addition to those of Mercury and Venus, and whereby both these models rule out solid celestial orbs that cannot interpenetrate, if not excluding interpenetrating fluid orbs.

However, Wittich's Capellan model of the Martian orbit contradicted Copernicus's model in which Mars at opposition is nearer to the Earth than the Sun is, whereby if true the Solar and Martian orbits must intersect in all geoheliocentric models. Thus the question of whether the daily parallax of Mars was ever greater than that of the Sun was crucial to whether Wittich's (and indeed also Praetorius's and Ursus's) model was observationally tenable or not. It seems Tycho Brahe eventually came to the conclusion by 1588 that Mars does come nearer to the Earth than the Sun is, albeit contradicting his earlier conclusion by 1584 that his observations of Mars at opposition in 1582-3 established it had no discernible parallax, whereas he put the Sun's parallax at 3'. Thus Brahe's 1588 model crucially contradicted both Wittich's and also Ursus's geoheliocentric models at least in respect of the dimensions of the Martian orbit, by positing its intersection with the Solar orbit.

However, having failed to find any Martian parallax greater than the Solar parallax, Tycho had no valid observational evidence for his 1588 conclusion that Mars comes nearer to the Earth than the Sun [5], and nor did anybody else at that time,[6] whereby Tycho's uniquely distinctive geoheliocentric model had no valid observational support in this respect, and it seems its credibility rested solely upon his aristocratic social status rather than any scientific evidence. And this failure to find any Martian parallax in effect also refuted Copernicus's heliocentric model in respect of its Martian orbit, and supported the geocentric models of Ptolemy and the Capellan geoheliocentric model of Wittich and Praetorius and also Ursus's more Tychonic model, which differed from Tycho's only in respect of its non-intersecting Martian and Solar orbits and its daily rotating Earth.

It seems a primary purpose of Wittich's Capellan model was to save the integrity of solid celestial orbs, and the only planetary models compatible with solid celestial orbs were the Ptolemaic, Copernican and Wittichan Capellan (including Praetorius's) planetary models. But with the observational refutation of the Ptolemaic model by the telescopic confirmation of the phases of Venus in 1610, this left only the Copernican and Wittichan Capellan models compatible with both solid orbs and the phases of Venus. But only the Wittichan system was also compatible with the failure to find any stellar parallax predicted by all heliocentric models, in addition to also being compatible with the failure to find any Martian parallax that refuted both the Copernican and Tychonic models.

Thus by 1610 it seems the only observationally tenable candidate for a planetary model with solid celestial orbs was Wittich's Capellan system. Indeed it also seems it was even the only planetary model that was generally observationally tenable, given the twin failures to find any stellar annual parallax nor any Martian daily parallax at that time.[7] However, insofar as it was accepted that comets are superlunary and sphere-busting, whereby solid celestial orbs are impossible and thus intersecting orbits cease to be impossible, then this thereby also admitted the model of Ursus (and Origanus) as also observationally tenable, along with Wittich's Capellan system (and thus also Praetorius's), whilst the Ptolemaic model was ruled out by the phases of Venus, all heliocentric models by the perceived absence of any annual stellar parallax, and both the Copernican and Tychonic models were also refuted by the absence of any Martian daily parallax.[8]

In his Nicolaus Copernicus-biography written in 1654, Pierre Gassendi classified him as one of the "Copernicans" before 1615.

[edit] Notes ^ Owen Gingerich, The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus, Penguin, ISBN 0143034766 ^ See The Wittich Connection by Gingerich & Westman, 'Transactions of the American Philosophical Society' Vol 78, Part 7, 1988 ^ see p139 of The Wittich Connection by Gingerich & Westman, or p30 of Jarrell's The contemporaries of Tycho Brahe in Taton & Wilson 1989 ^ p34 Taton & Wilson 1989 ^ See p71 Gingerich & Westman 1988 ^ In fact given the modern values of some 9" for solar parallax and a maximum of some 23" for Martian parallax, they were indetectable by naked eye or even by telescopic instrumentation at the time. ^ However, van Helden's 1989 The telescope and cosmic dimensions reports: "In his Astronomia nova Kepler argued that [Tycho Brahe's measurements of the diurnal parallax of Mars] showed that Mars's parallax was never greater than 4', which put a limit of 2' on the Sun's parallax...". See p109 Taton & Wilson 1989. But inasmuch as this seems to assert Kepler found Brahe's observations showed Mars's parallax to be as great as 4', it is contrary to the impression given by Gingerich & Westman 1988 and also by Dreyer's 1890 and Gingerich's 1982 that Kepler found no justification in Brahe's observations for any discernible Martian parallax. ^ Longomontanus's semi-Tychonic model would also have been ruled if it put Mars closer to the Earth than the Sun at any point.

[edit] Literature van Helden Galileo and telescopic astronomy Taton & Wilson 1989 Dreyer Tycho Brahe 1890 Gingerich 1982 Dreyer and Tycho's World System Sky & Telescope 64 1982, p138-40 Gingerich & Westman The Wittich Connection, Transactions of the American Philosophical Society Vol 78, Part 7, 1988 [1] Jarrell The contemporaries of Tycho Brahe in Taton & Wilson 1989 Taton & Wilson Planetary astronomy from the Renaissance to the rise of astrophysics Part A: Tycho Brahe to Newton Cambridge University Press 1989 R. Westman (Ed) The Copernican Achievement 1976 University of California Press

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--Logicus (talk) 15:46, 27 January 2008 (UTC)

Capella, Heraclides, and the phases of Venus

The article presently states that the phases of Venus was "a novel fact objectively first predicted by Heraclidean and Capellan geoheliocentric planetary models in antiquity." The text of Martianus Capella, De Nuptiis, 882 speaks of the bounded elongation of Venus, but does not suggest that this implies that Venus ever assumes a crescent shape. If there is not a text for such a prediction, I suggest making it read "a novel fact already implied by the Heraclidean ..." --SteveMcCluskey (talk) 19:40, 19 April 2008 (UTC)

Thanks, will reconsider this point.--Logicus (talk) 14:52, 18 May 2008 (UTC)

Whether Capellus himself actually drew this logical inference of his model is logically irrelevant to the point made here that it is an objective logical consequence/prediction of the model, and nor do I know of any evidence that Heraclides did either. Nevertheless arguably the point does need clarification and editing for this and other reasons. I provisionally propose the following for discussion and criticism.

"a novel fact logically implied by the Heraclidean geoheliocentric planetary model in antiquity in which at least Venus and Mercury orbit the Sun(Fn),...

Fn By when this logical inference of the heliocentric model and all geoheliocentric models in which at least Venus and Mercury orbit the Sun was first actually drawn is undated by historians of science. But in Chapter 10 of Book 1 of his De Revolutionibus Copernicus mentions the implication that Venus and Mercury should exhibit phases like the Moon if they were 'below' the Sun as having been inferred by "the followers of Plato" and his Timaeus, along with the implication that they should sometime eclipse the Sun. But Copernicus says because both predictions were apparently refuted, they therefore put Venus and Mercury above the Sun. But he never names or dates these "followers of Plato" and hence when these two inferences were drawn."

But Copernicus’s analysis needs further consideration, especially since Ptolemy also implies some phasing.

Does anybody know when the specific phases of Venus that refute pure geocentrism were first predicted ? --Logicus (talk) 18:10, 19 May 2008 (UTC)

Proposed edit:McCluskey has implicitly raised the interesting question of when the phases of Venus were first inferred from geoheliocentric and heliocentric planetary models. But it is not the case, as he seems to imply, that bounded elongation itself implies Venus sometimes has a crescent shape, since it does not in the context of the Platonic geocentric planetary model in which it is a superior planet, so perhaps one would not expect Capellus to predict it from bounded elongation. And nor, as he seems to imply, is the heliocentric and geoheliocentric prediction of the phases of Venus involved here the prediction that it is sometimes crescent shaped, so again one would not expect Capellus to predict it. Rather it is the prediction that it is gibbous or full in conjunction, unlike in Ptolemaic geocentrism in which it is never more than semi-circular at most, as well as also being crescent shaped in opposition, as it is also in Ptolemaic geocentrism, and thus exhibits a full set of phases like the Moon.

Further analysis of this whole complex issue of the phases of Venus leads me to propose the following more fully explanatory edit of an issue about which there is apparently much confusion about it in the academic field.

"But in 1610 Galileo's novel telescopic confirmation, published in his 1613 Letters on Sunspots, that Venus has a full set of phases like the Moon refuted the Ptolemaic geocentric model, which implied they are only crescents in conjunction, just as in opposition, except smaller, whereas they are gibbous or full in conjunction. This crucial novel fact was logically implied by the Heraclidean, Capellan and Tychonic geoheliocentric planetary models, according to all of which at least the orbits of Venus and Mercury are centred on the Sun rather than the Earth, as well as by the pure heliocentric model.(Fn) Consequently this left only the Copernican and Wittichan...

Fn But the full set of phases cannot be perceived by naked-eye observation, to which the prediction appears at best unconfirmed if not plainly refuted. When this objective logical implication of all such models was first consciously inferred by anybody seems to be undated by historians of science. But in an early work Kepler seems to have regarded it as a consequence of his heliocentric planetary model in rejecting the Platonic theory that the planets shine by reflected sunlight because no phases of Venus could be seen in that pre-telescopic period. [See p411 of Dreyer's 1953 History of Astronomy] However, Kuhn's implication on p222-3 of his 1957 The Copernican Revolution that Copernicus inferred the phases of Venus from heliocentrism in Chapter 10 of Book 1 of his De Revolutionibus as a decisive observational difference between the Ptolemaic and heliocentric models is evidently mistaken. For as in the text of that chapter Kuhn presents on p177, it seems Copernicus is only reporting without endorsing the geocentric Platonists' argument that the orbits of Venus and Mercury must lie beyond the Sun as in Timaeus, rather than beneath the Sun but still within geocentrism, because otherwise "they would appear as half or partial circles". Within pure geocentrism, if Venus's orbit lay within the Sun's orbit as in the Ptolemaic model, then it would predict crescent shaped or at most semi-circular phases at the maximum of quadrature as evident from Kuhn's p223 diagram 44(a). But if its orbit circumscribed the Sun's and with its 47 degrees bounded elongation it would always appear at least gibbous or full but never as crescents or even semi-circular. Kuhn's mistaken and misleading diagram Fig 44(c)on p223 also has Venus's horns pointing the wrong way round, to the right rather than the left when waning, as not incorrectly portrayed in the excellent Wikipedia diagram of the phases of Venus [[[Phases-of-Venus.svg]]] in its article on Venus. It seems no historian of science has presented any evidence that Copernicus predicted the full range of phases of Venus that follow from heliocentric and geoheliocentric planetary models. Thus it seems to be an open question of who if anybody before Kepler deduced that heliocentric and/or geoheliocentric models imply the crucial fact against pure geocentrism that Venus has a full set of phases like the Moon, and so is also most crucially gibbous or full in conjunction, unlike when it is an inferior planet in Ptolemaic geocentrism when it is crescent shaped or at most semi-circular in conjunction, and also unlike when it is a superior planet in Platonic geocentrism, when it is never less than gibbous or full." --Logicus (talk) 18:14, 20 May 2008 (UTC)