Talk:Galileo Galilei

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Gilbert and magnetism

The text seems to belittle Gilbert's work on the magnet. Possibly, this is done to put Galileo in a good light. Oddly, no attempt is made to belittle earlier Chinese work on the magnet. —Preceding unsigned comment added by 86.180.34.206 (talk) 10:53, 31 July 2010 (UTC) No attempt is made to belittle work on the magnet by Thales. —Preceding unsigned comment added by 93.97.95.95 (talk) 12:29, 18 November 2010 (UTC) See Thales. —Preceding unsigned comment added by 93.97.95.95 (talk) 12:33, 18 November 2010 (UTC)

See the article on Electricity, which gives more on the work of Thales on magetism and Ike Davis electricity than the Thales article. —Preceding unsigned comment added by 86.162.39.190 (talk) 12:24, 1 January 2011 (UTC)

The allegedly extant distinction between "qualitative" and other methods is unreal, any way. —Preceding unsigned comment added by 86.162.39.190 (talk) 12:39, 1 January 2011 (UTC)

Relativity

In the PHYSICS section Galileo's principle of relativity is stated as "the laws of physics are the same in any system that is moving at a constant speed in a straight line". That should be "circular motion". It is Newton who transformed it to linear motion.--Cem kamozut (talk) 21:38, 2 December 2010 (UTC)

I think the section refers to movement of a trajected body in the gravitational system on Earth. Then it should be "straight line", not "circular movement", because the later refers to a heavenly body in the solar system. Newton was the first to generalize the physics so that the heavenly bodies and the earth trajected bodies were equated to be governed by the same one natural law. Rursus dixit. (^mbork³!) 15:04, 29 December 2010 (UTC)

Vehemently suspect for heresy?

For fun, what's

vehemently suspect of heresy

in Latin? I feel like that applies to me too, and would like it as a slogan. Rursus dixit. (^mbork³!) 15:13, 29 December 2010 (UTC)

vehementer suspectus haeresim. Rursus dixit. (^mbork³!) 23:27, 29 December 2010 (UTC)

The original copy of the Inquisition's judgement against Galileo (presumably in Latin) is no longer extant. The earliest surviving copy is in Italian, which, as transcribed by Favaro has vehementemente sospetto d'heresia. One of the notices effecting the Inquisition's order to publish a notification of Galileo's condemnation in every Catholic diocese rendered it vehementer suspectum ... de haeresi in Latin. This is obviously in the accusative case. The nominative would have had suspectus in place of suspectum.

David Wilson (talk · cont) 02:48, 30 December 2010 (UTC)

OK, thanks! I googled and saw some diverse bad grammar cases, I think it should be either Inquisitio Galileum vehementer suspectum haeresim accusaverunt (predicative) or Galileus Galilei, vehementer haeresis suspectus, scientiae contribuit inaestimabile (embedded relative clause). Maybe. Just for fun. Rursus dixit. (^mbork³!) 16:48, 1 January 2011 (UTC)

Rursus, who seems to be a Swede, is, as he says, contributing for "fun".

He might try a more serious approach, referring to the theory of relativity, for instance. —Preceding unsigned comment added by 86.145.224.59 (talk) 11:20, 3 January 2011 (UTC)

I wrote above:

"The original copy of the Inquisition's judgement against Galileo (presumably in Latin) ... "

According to Maurice Finocchiaro's Retrying Galileo (p.40) this presumption would appear to have been incorrect. Finocchiaro says that the Inquisition's practice was to issue the sentence and abjuration of a convicted person in his or her native language, which was Italian in Galileo's case. So presumably the earliest surviving Italian versions would have been pretty close to verbatim copies of the original.

David Wilson (talk · cont) 14:56, 4 March 2011 (UTC)

Edit request from Elitak, 5 January 2011

{{edit semi-protected}}
 Done (Sort of—see response below).

I found that most of these sentences could have been phrased better:

According to Galileo, stellar disk diameters typically measured a tenth the diameter of the disk of Jupiter (one five-hundredth the diameter of the sun), although some were somewhat larger and others substantially smaller. Galileo argued that stars were suns, and that they were not arranged in a spherical shell surrounding the solar system but rather were at varying distances from Earth. Brighter stars were closer suns, and fainter stars were more distant suns. Based on this idea and on the sizes he claimed for stellar disks, he calculated stars to lie at distances ranging from several hundred solar distances for bright stars to over two thousand solar distances for faint stars barely visible to the unaided eye, with stars visible only with the telescope being further still. These distances, although too small by modern standards, were far larger than planetary distances, and he used these calculations to counter anti-Copernican arguments that distant stars were an absurdity.[87]

The last part is the one with which I take most issue. It's essentially a double-negative because of the words:

• counter
• anti- / absurdity (used in parallel)

The simpler way of saying this is that his findings supported the Copernican model that stars were very far away.

Here's my proposed rewrite:

According to Galileo, stellar disk diameters typically measured ¹/₁₀ the diameter Jupiter, itself ¹/₅₀₀ the diameter of the Sun, with substantial variations. In contrast to the Copernican view that stars were differently-sized disks arranged in a spherical shell surrounding the solar system, Galileo thought they were distant suns whose brightness depended on their proximity to the Earth. Based on this idea and the stellar disk diameters he recorded, he calculated bright stars to lie at distances as close as several hundred solar radii; faint stars, up to over two thousand; and stars visible only with a telescope, yet farther. These distances, while still much shorter than modern estimates, were many times longer than planetary ones, as in the Copernican model. He used his calculations to support the popularly-contested notion of very distant stars. Galileo argued that if anything, the stellar distances he measured were not great enough, since when compared to the Sun, the stars had no discernible effect on the Earth's seasons.[87]

See reference #87.1 pages 172-174 for the added detail in the last sentence. Perhaps it should be omitted, since I didn't explain how Galileo believed that stars in closer proximity should affect the Earth. Also, I don't know myself whether Galileo incorrectly believed that the solar distance at the perihelion and aphelion played a greater role than the Earth's axial tilt; I left this unaddressed. Hopefully, someone with deep knowledge of the subject can proof this, because I really just wanted to make adjustments to the grammar, but got a bit carried away and changed some of the semantic content as well. In any case, I think the article could benefit from some more detail of Galileo's stellar theory, but I'm not prepared for such extensive amendments.

Elitak (talk) 13:28, 5 January 2011 (UTC)

I believe there were (and still are) more problems with this passage than merely poor phrasing. While your rewrite has certainly alleviated some of these problems, I don't believe it has eliminated them entirely. Even as rewritten, the passage seems to me to suggest that Galileo thought he could fairly reliably estimate the relative distances to the stars (as multiples of the distance from the Earth to the Sun). I don't believe any of the cited references supports that suggestion, and I strongly doubt that he ever laboured under such a misapprehension. What he does do in the first two references—as well as in a manuscript discussed in the third—is simply deduce how far away stars of certain specified apparent sizes would have to be if they were assumed to be about the same actual size as the Sun. I can see no indication in any of the references that he would have regarded it as likely that the true sizes of these stars were close to that of the Sun's, or consequently that his calculated distances were therefore likely to be anywhere close to their true distances. It seems to me that about the most one can say is that he obviously considered it reasonable to suppose that their sizes might be similar to that of the Sun's.

In the first two references—which are primary sources—the purpose of the calculation was simply to rebut the argument of anti-Copernicans that the absence of any annual parallax or changes in the apparent sizes of the fixed stars implied that they would have to be inconceivably large (with a diameter larger than that of the Earth's orbit, according to Tycho Brahe) if Copernicus's theory were correct. Galileo's point was that even if a star of roughly average apparent size were no larger than the Sun it would still be too far away for its annual parallax and change in apparent size to be readily detectable.

The third reference (of which a version is available online here) discusses a manuscript in which Galileo records some observations, thought to have been made in 1617, of the Mizar-Alcor multiple star system. From his estimate of 3 arcseconds for the radius of the larger of what appeared to him to be two stars, he calculated that if the actual size of this star were the same as that of the Sun then it would be at a distance of about 300 astronomical units. If he thought that this might have been its true distance at that time, it seems unlikely that he would have still been of the same opinion by the time he wrote the second of the two references—his Letter to Ingoli—in 1624. A star only 300 astronomical units distant at Mizar's latitude (viz. 56°) would have had a parallax large enough to be easily detectable by Galileo and other astronomers amongst his supporters. Given that they were very keen to discover any such strong evidence in favour of the Copernican theory, it seems quite likely that by 1624 they would have established that Mizar's parallax was undetectable, and therefore that it must have been much further away than 300 astronomical units (if, as they believed, the theory were correct). I therefore don't believe this reference (or either of others for that matter) can be used as support for the claim that Galileo believed there were stars as close as a few hundred astronomical units distant from the Sun.

Over the next few days I'll try to put together a replacement which is a more accurate account of what is actually contained in the sources cited, but I would be delighted if someone else were to beat me to it

David Wilson (talk · cont) 16:47, 6 January 2011 (UTC)

That's fine with me. I'm totally ignorant on this subject and just wanted to reduce verbosity and increase clarity by a small measure. It didn't strike me as an easy matter to measure a stellar disk and approximate the distance of that star given the crude tools of those days; the use of annual parallaxes makes much more sense and is probably the better way with which to frame his understanding of the stars.

Elitak (talk) 05:11, 8 January 2011 (UTC)

I have now amended the paragraph in question. I have omitted some material that wasn't particularly relevant to the amended exposition. If anyone believes this material should have been retained it could be reinserted as a subsequent paragraph.

David Wilson (talk · cont) 16:58, 5 March 2011 (UTC)

suggestion

it may be better if the word thermometer in section ( technology ) convert here Galileo thermometer as a complete for the article —Preceding unsigned comment added by 196.221.234.11 (talk) 17:46, 8 January 2011 (UTC)

Please post new talk page messages at the bottom ans sign them with four tildes (~~~~)? Thanks.

Good catch!  Done. DVdm (talk) 18:14, 8 January 2011 (UTC)