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Did Galileo Galilei believe in astrology?

Galileo not only believed but taught and actively practiced astrology, like Ptolemy and Kepler before him. His primary source might have been Porphyry’s commentary on Ptolemy's Tetrabiblos. In ...
Conifold's user avatar
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Why did Galileo express himself in terms of ratios when describing laws of accelerated motion?

Galileo followed a venerable tradition of distinguishing numbers, magnitudes of different kinds (lengths, times, areas, etc.) and ratios. This is somewhat analogous to the strictures of modern ...
Conifold's user avatar
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13 votes

Is Spivak right in what he says about Galileo?

Yes, indeed when trying to obtain the law of falling bodies, Galileo's first conjecture was that the speed is proportional to the distance traveled. After some contemplation, Galileo understood that ...
Alexandre Eremenko's user avatar
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Is Koestler's ‘The Sleepwalkers’ still well regarded? Is there a more recent similar source?

As the question says, Arthur Koestler in 'The Sleepwalkers' "isn't shy of taking a point of view of the events he's describing". Koestler's book offered a gripping collective account of ...
terry-s's user avatar
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Did Galileo Galilei believe in astrology?

The Galileo's astrology activities are well summarized in Conifold's answer. But, in relevance to the question at hand (did he believe it worked) I'd like to make a couple of points: The fact that ...
Tziolkovski's user avatar
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What are the origins of Galileo's paradox?

The answer depends on what "this" means. According to Mancosu's Measuring the Size of Infinite Collections of Natural Numbers (reprinted in his book Abstraction and Infinity): It is actually ...
Conifold's user avatar
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Did Galileo really see Galilean Moons?

There can be no doubt that he has seen them, for the simple reason that he determined their periods and configuration correctly, and published them. Therefore the other things (magnification of his ...
Alexandre Eremenko's user avatar
8 votes

Is Spivak right in what he says about Galileo?

Yes, Galileo made that error (and so did Descartes). Only later did he realise that the speed is proportional to the time ellapsed, not to the distance already covered. I suggest that you read The new ...
José Carlos Santos's user avatar
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Who studied kinematics before Galileo? Did Galileo base his kinematic research on the previous work of any other scientist?

Kinematics was distinguished from dynamics by the Merton school (a.k.a. Oxford calculators) of scholastics in 14th century, who worked out kinematics of uniformly accelerated motion. In particular, ...
Conifold's user avatar
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6 votes

How did people believe Aristotle's law of gravity for so long?

The assumption that people believed Aristotle’s law for so long is highly questionable. Aristotle’s law occurs in a philosophical context. He introduces it in order to argue that there can be no such ...
Viktor Blasjo's user avatar
6 votes

What's the true story about Galilei?

As Mauro Allegranza mentioned, the literature is enormous. To put it short, Galileo was censored. He was given a warning not to advocate Copernican theory as an established fact but was permitted to ...
Alexandre Eremenko's user avatar
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Where did Galileo say "All truths are easy to understand once they are discovered. The point is to discover them."?

Dialogo sopra i due massimi sistemi del mondo (1632), Day two: SAGR. Tali [facili da intendersi] sono tutte le cose vere, doppo che son trovete; ma il punto sta nel saperle trovare. [Stilmann Drake ...
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How did heliocentrism survive after Galileo's sentencing?

This will answer two out of three parts of the question: (a) 'Why didn't the church go after Isaac Newton?' It was not at all the whole church that was involved in the Galileo affair: it was the ...
terry-s's user avatar
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Did Galileo state the principle of equivalence in full generality?

Not quite. This is what Galileo stated in the Two New Sciences (1638) through his character Sagredo (honest inquirer open to arguments from both sides): "But I, Simplicio, who have made the test ...
Conifold's user avatar
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How did heliocentrism survive after Galileo's sentencing?

This question discusses the common assumption that the only issue of the Galileo trial was heliocentrism. Briefly, some scholars have argued that an additional issue was atomism and its difficult ...
Mikhail Katz's user avatar
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What was Galileo's opinion of Kepler's work?

Yes, Galileo knowed Kepler's, as well as Tycho's, works. There is an extant copy of Tycho's Progymnasmata with Galileo's annotations, and we have an annotation from Galileo on Kepler's De stella nova: ...
Mauro ALLEGRANZA's user avatar
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What did Galileo's "pulsilogon" look like?

According to the medical journal article The History of Instrumental Precision in Medicine, referring to the pulsilogon : Unclaimed by Galileo, it was attributed to Paolo Sarpi, and clearly enough ...
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What's the difference between Galileo's "impeto" and "momento"?

Momento is an object’s tendency to move, much like a net force acting on an object that results in motion. For example, lighter objects move slower in a medium than heavier objects in the same medium....
Andrew R.'s user avatar
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How Galileo could both possibly say that Earth is revolving around the Sun and develop the Galilean relativity?

For Galileo, the relativity principle was an observational principle. When he writes about the thought experiment on a moving ship where the observer cannot recognize that there is movement, it is ...
cktai's user avatar
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When was Galileo's De Motu (Antiquiora) Made Available to the Public?

TL;DR The publication history of Galileo's De motu is essentially as outlined in the question: In 1854 Albèri published an initial portion, in 1883 Favaro published the balance of the work, and the ...
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2 votes

Biographical articles on Newton and Galileo by physicist or historian

Historian Pietro Redondi wrote a fascinating account of Galileo's tumultuous career in a book entitled Galileo Heretic. There is certainly more detail here than you will need for your lecture but on ...
Mikhail Katz's user avatar
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Biographical articles on Newton and Galileo by physicist or historian

I am not sure how much detail you are looking for. MacTutor has decent short biographies of both Galileo and Newton by O'Connor and Robertson. Einstein wrote a eulogy of Newton in 1927, which also ...
Conifold's user avatar
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What is the explanation of rope's strength in Galileo's Two New Sciences?

In this passage Galileo is explaining how a bundle of multiple short fibers twisted into a rope functions. He is analogizing a fiber in the bundle to a fiber held between fingers, and notes that it ...
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Questions regarding "Two New Sciences" by Galileo Galilei

ONE: As others have stated, real numbers were questionable at the time, so to overcome this deficency, numbers were constructed based on magnitudes. In Euclidean geometry, magnitudes can only be ...
Andrew R.'s user avatar
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Questions regarding "Two New Sciences" by Galileo Galilei

Why do we need to prove such a thing since the statement of the theorem is the direct consequence of this relation speed = distance/time? This is exactly what he tries to prove here. The difference ...
Alexandre Eremenko's user avatar
2 votes

Did Galileo Galilei believe in astrology?

Rutkin D., Galileo Astrologer, Galileana II 2005 p 107-143 "Favaro (in vol.19 of the Ed.N) transcribed and published the astrological judgments written in Latin of Galileo's two daughters which ...
sand1's user avatar
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2 votes

What was the aperture of the first Galileo's telescope?

Galileo's most famous invention was the telescope. Galileo made his first telescope in 1609, modeled after telescopes produced in other parts of Europe that could magnify objects three times and its ...
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