Some science historians declined to comment on the finding before they had scrutinized the article. Galileo wrote the letter to Benedetto Castelli, a mathematician at the University of Pisa in Italy. He argued that the scant references in the Bible to astronomical events should not be taken literally, because scribes had simplified these descriptions so that they could be understood by common people.
Most crucially, he reasoned that the heliocentric model of Earth orbiting the Sun, proposed by Polish astronomer Nicolaus Copernicus 70 years earlier, is not actually incompatible with the Bible. Galileo, who by then was living in Florence, wrote thousands of letters, many of which are scientific treatises. Copies of the most significant were immediately made by different readers and widely circulated. Of the two versions known to survive, one is now held in the Vatican Secret Archives.
Galileo enclosed with that letter a less inflammatory version of the document, which he said was the correct one, and asked Dini to pass it on to Vatican theologians. At least a dozen copies of the version Galileo sent to Dini are now held in different collections.
The changes are telling. This suggests that Galileo moderated his own text, says Giudice. Bruno is burnt at the stake. Copies of this letter are circulated. Books supporting the Copernican model are banned. The Inquisition summons Galileo to Rome to stand trial. He is issued with a prison sentence, later commuted to house arrest, under which lived the last nine years of his life.
When his one day at the Royal Society was finished, he idly flicked through the online catalogue looking for anything to do with Castelli, whose writings he had recently finished editing. The details of this episode are far from straightforward, and remain disputed even today. See Shea and Artigas ; Fantoli In , Galileo published The Assayer , which deals with the nature of comets and argues they are sublunary phenomena.
It also contains passages suggestive of atomism, a heretical doctrine, for which the book was referred to the Inquisition, which dismissed the charge. Printing was completed in Florence by February Shortly afterwards, the Inquisition banned its sale, and Galileo was ordered to Rome for trial.
There is more about these events and their implications in the final section of this article, Galileo and the Church. In , while Galileo was confined to his villa in Arcetri, his beloved eldest daughter died Sobel Around this time, he began work on his final book, Discourses and Mathematical Demonstrations Concerning Two New Sciences , based on the mechanics he had developed early in his career.
The manuscript was smuggled out of Italy and published in Holland by the Elzeviers in Galileo died early in , and due to his condemnation, his burial place was obscure until he was re-interred in More recently, J. Heilbron has written a magnificent biography, Galileo , that touches on all the multiple facets of his life.
He is renowned for his discoveries: he was the first to report telescopic observations of the mountains on the moon, the moons of Jupiter, the phases of Venus, and the rings of Saturn.
He invented an early microscope and a predecessor to the thermometer. In mathematical physics—a discipline he helped create—he calculated the law of free fall, conceived of an inertial principle, determined the parabolic trajectory of projectiles, and advocated the relativity of motion. This is no small set of accomplishments for one seventeenth-century Italian, who was the son of a court musician and who left the University of Pisa without a degree.
Momentous figures living in momentous times are full of interpretive fecundity, and Galileo has been the subject of manifold interpretations and much controversy. Philosophically, Galileo has been used to exemplify many different themes, usually as a personification of whatever the writer wished to make the hallmark of the Scientific Revolution or of the nature of good science—whatever was good about the new science or science in general, it was Galileo who started it.
More philosophically, many ask how his mathematical practice relates to his natural philosophy. Or did he have no method and just fly like an eagle in the way that geniuses do Feyerabend ? Alongside these claims there have been attempts to place Galileo in an intellectual context that brings out the background to his achievements. Still, almost everyone working in this tradition seems to think the three areas—physics, astronomy, and methodology—are somewhat distinct and represent different Galilean endeavors.
More recent historical research has followed contemporary intellectual fashion and shifted foci, bringing new dimensions to our understanding of Galileo by studying his rhetoric Finocchiaro ; Moss ; Feldhay ; Spranzi , the power structures of his social milieu Biagioli ; Biagioli , his personal quest for acknowledgment Shea and Artigas , and more generally emphasizing the larger social and cultural history Reeves ; Bucciantini, et al.
In an intellectualist recidivist mode, this entry will outline his investigations in physics and astronomy and exhibit, in a new way, how these all cohered in a unified inquiry. In setting out this path, we shall show why, at the end of his life, Galileo felt compelled in some sense of necessity to write the Two New Sciences , which stands as a true completion of his overall project and is not just a reworking of his earlier research that he reverted to after his trial, when he was under house arrest and going blind.
Particularly, we shall try to show why both of the two new sciences, especially the first, were so important—a topic not much treated except recently Biener ; Raphael In passing, we shall touch on his methodology and his mathematics, and here refer you to some of the recent work by Palmieri ; At the end, we shall add some words about Galileo, the Catholic Church, and his trial.
Galileo signaled this goal clearly when he left Padua in to return to Florence and the court of the Medici. This was not just a status-affirming request, but also a reflection of his programmatic aims. What Galileo accomplished by the end of his life was a reasonably articulated replacement for the traditional set of analytical concepts connected with the Aristotelian tradition of natural philosophy.
His way of thinking became the way of the Scientific Revolution and yes, there was such a revolution, pace Shapin and others; see the selections in Lindberg and Westman ; Osler Some scholars might wish to describe what Galileo achieved in psychological terms, as an introduction of new mental models Palmieri or a new model of intelligibility Machamer ; Machamer, a; Adams, et al. In their place, he left only one element, corporeal matter, whose properties and motions he described using the mathematics of proportional relations typified by the Archimedian simple machines—the balance, the inclined plane, and the lever—to which Galileo added the pendulum Machamer a; Machamer and Hepburn ; Palmieri In doing so, Galileo changed the acceptable way of talking about matter and its motion, and so ushered in the mechanical tradition that characterizes so much of modern science, even today.
See Dijksterhuis ; Machamer, et al. Perhaps he did not realize that this was his grand project until the time he actually wrote the Two New Sciences in the mids. Despite working on problems of the nature of matter from onwards, he could not have written his final work much earlier than ; certainly not before the Starry Messenger of , and probably not before the Dialogue Concerning the Two Chief World Systems of He had thought deeply about the nature of matter before and had tried to work out how best to describe matter, but before , he did not have the theory and evidence he needed to support his claims about a unified, singular matter.
And this he did not accomplish until the Dialogue. Galileo began his critique of Aristotle in a treatise he drafted around , titled De Motu On Motion. For Aristotle, the matter of the terrestrial realm within the sphere of the moon is of four elemental kinds—earth, water, air, and fire. These possess two formal principles that give rise to their natural motion: heaviness gravitas ; in earth and water and lightness levitas ; in air and fire. Galileo, using an Archimedean model of floating bodies, and later the balance, argues that there is only one principle of motion—heaviness.
Bodies move upward not because they have a natural lightness, he says, but because they are displaced or extruded by other heavier bodies moving downward. So on his view, heaviness is the cause of all natural terrestrial motion. This move left Galileo with a problem: what is heaviness and how is it to be described? In De Motu , he argued that the moving arms of a balance could be used as a model for treating all problems of natural motion.
In this model, heaviness is the proportionality of the weight of an object on one arm of the balance to the weight of another body on the other arm.
In the context of floating bodies, heaviness is the weight of one body minus the weight of the medium. Galileo quickly realized these characterizations were insufficient, and so began to explore how heaviness might be related to specific gravities; i.
He was trying to figure out the concept of heaviness that is characteristic of all matter. What he failed to work out—and this was probably the reason why he never published De Motu —was this positive characterization of heaviness.
There seemed to be no way to find a standard measure of heaviness that would work across different substances. At this point, he did not have a useful replacement for Aristotelian gravitas. A while later, in his manuscript version of Le Meccaniche On Mechanics , Galileo introduced the concept of momento , a quasi force that applies to a body at a moment, and which is somehow proportional to weight or specific gravity Galluzzi Still, he had no good way to measure or compare specific gravities of bodies of different kinds, and his notebooks during this early seventeenth-century period reflect his trying again and again to find a way to bring all matter under a single proportional measuring scale.
He tried to study acceleration along an inclined plane and to find a way to think of what changes acceleration brings to momento. Yet the details and categories of how to properly treat weight and movement eluded him.
Galileo accepted, probably as early as the draft of Le Meccaniche , that natural motions might be accelerated.
Particularly in the cases of the pendulum, the inclined plane, free fall, and projectile motion, Galileo must have observed that the speeds of bodies increase as they move downwards and, perhaps, do so naturally. But that accelerated motion is properly measured against time is an idea he realized only later, chiefly through his failure to find any satisfactory dependence on place and specific gravity.
Also at this time, he began to think about percussive force. For many years, he thought that the correct science of these phenomena should describe how bodies change according to where they are on their paths. Specifically, it seemed that height is crucial. Since they generally work by establishing static equilibrium, time is not a feature of their action one would normally attend to.
In discussing a balance, for instance, one does not normally think about how fast an arm of the balance descends, nor how fast a body on the opposite arm is rising though Galileo does in his Postils to Rocco circa —45; see Palmieri The converse is also true. It is difficult to model dynamic phenomena that involve rates of change as balance arms moving upwards or downwards because of differential weights.
Throughout his life, he could not find systematic relations among specific gravities, heights of fall, and percussive forces. In the period —9, Galileo experimented with inclined planes and, most importantly, pendulums. These studies again exhibited to Galileo that acceleration and, therefore, time is a crucial variable. Moreover, the isochrony of the pendulum—the period depends only on the length of the cord, regardless of the weight of the bob—went some way towards showing that time is a possible term in the equilibrium or ratio that needs to be made explicit to represent motion.
It also shows that, in at least one case, time can displace weight as a crucial variable. The law of free fall—i. At first, Galileo attempted to represent this phenomenon with a velocity-distance relation, and the equivalent mean proportional relation. Yet Galileo would not publish anything making time central to his analysis of motion until , in the Two New Sciences. In , Galileo began his work with the telescope.
However, they are remarkable insofar as they are his start at dismantling the celestial-terrestrial distinction entrenched in Aristotelian cosmology Feyerabend Perhaps the most unequivocal case of this is when he analogizes the mountains on the moon to mountains in Bohemia in the Starry Messenger.
Also crucial was his discovery of the four moons circling Jupiter, which lent credence to the Copernican system since it meant that a planet-moon arrangement was not unique to the Earth.
The abandonment of the dichotomy between heavens and earth implied that all matter, whether celestial or terrestrial, is of the same kind. Further, if there is only one kind of matter, there can be only one kind of natural motion—one kind of motion that this matter has by nature.
So it has to be that one law of motion will hold throughout the terrestrial and celestial realms. This is a far stronger claim than he had made in , which concerned only the terrestrial elements.
A few years later, in his Letters on Sunspots , Galileo offered new telescopic evidence that supported the Copernican theory. But these observations also served as additional reasons for dissolving the celestial-terrestrial distinction.
One was that the sun is not an immutable aetherial sphere, but has changing spots maculae on its surface. Another was that the sun rotates circularly around its axis, like the Earth. A third was the discovery that Venus undergoes a full sequence of phases like the moon , which entails that Venus revolves around the sun, and suggests that the Earth is likewise a celestial body moving around the sun.
Certainly the phases of Venus contradicted the Ptolemaic ordering of the planets. Later, in , Galileo argued for a quite mistaken material thesis.
In The Assayer , he tried to show that comets are sublunary phenomena and that their properties could be explained by optical refraction. While this work stands as a masterpiece of scientific rhetoric, it is somewhat strange that Galileo should have argued against the superlunary nature of comets, which the great Danish astronomer Tycho Brahe had demonstrated earlier.
Yet even with all these developments, Galileo still needed to work out general principles concerning the nature of motion for this newly unified matter. For Galileo, by contrast, Copernicanism was also a commitment to a physically realizable cosmography.
Consequently, he needed to work out, at least qualitatively, a way of thinking about the actual motions of matter. He had to devise or shall we say, discover principles of local motion that would fit a central sun, planets moving around that sun, a whirling Earth, and everything on it. The Church, swayed by the Aristotelian Scholars declared that Galileo was contradicting scripture,. March 5, The Catholic Church formally declares the writings of Galileo banned, and warns Galileo not to "hold or defend his doctrines.
He retires to his home in Bellosguardo near Florence. Galileo writes his "Assayer He again travels to Rome hoping to appeal the decree. The Pope does not repeal the decree, but he does allow Galileo to write on both sides of the issue, noncomentally, and equally supportive of both sides of the issue, and without making any definite conclusions. Galileo publishes his great work, Dialogo sopra I due massimi sistemi del mondo, tolemaico e copernicano Dialogue Concerning the Two Chief World Systems--Ptolemaic and Copernican IN compliance with the Pope, the work is set as a conversation between two men discussing the Ptolemaic and Copernican systems.
Simply put, all hell brakes loose in Galileo's world. The Pope, infuriated at the content of "Dialogo," places him on trial for one thing after another. February Galileo is eventually placed on trial and at his old age, is forced to make the journey to Rome. He is under suspicion of "vehement suspicion of heresy," but is convicted of holding and teaching the Copernican belief.
He is placed under house arrest for eight years until his death. Despite his house arrest Galileo publishes Discorsi e dimostrazioni mathematiche intorno a due nuove scienze attenenti alla meccanica Dialogue Concerning Two New Sciences, a work about the principles of mechanics. Galileo makes the discovery, months before he went completely blind, that the moon makes monthly wobbles on its axis, called liberations.
January 8, Galileo Galilei dies from a long illness. The moon is an irregular, rough body, not smooth as scientists thought.
0コメント