Difference between revisions of "Galileo Galilei"

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-[[Image:Galileo.jpg|right|thumb|200px|'''Galileo Galilei'''<br> Subterman's portrait, circa 1640]]
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-'''Galileo Galilei''' (1564-1642), often referred to simply as '''Galileo''', was an [[Italy|Italian]] [[physicist]] and [[astronomer]] who improved the [[telescope]], contributed to the field of [[mechanical]] [[physics]], proposed the [[heliocentrism|heliocentric]] model of [[Copernicus]] as the accurate universal model, and later in life had a famous dispute with the [[Catholic Church]] in which they labeled him a [[heretic]].  The backdrop was the [[Reformation]]. Despite the Church being in a divided state, on this issue the [[Catholic Church]] spoke for all of Christianity. [[Protestant]]s [[Martin Luther]] and [[John Calvin]] had also both disputed the [[heliocentric]] model<ref>[http://books.google.com/books?id=JcMCmBnpHGsC&pg=PA155&dq=Galileo+Catholic+Priest&as_brr=3&ei=6BFJSZ2rD5qEkgSgzfSwAg#PPA155,M1 ''The Language of God: A Scientist Presents Evidence for Belief''], Francis S. Collins, Simon and Schuster, 2006, ISBN 0743286391, 9780743286398, 294 pages, p. 155</ref>.
-Galileo first came to prominence when, in 1604, he demonstrated that a [[supernova]] was further away from the earth than the [[moon]].  At the time that was shocking as it was not expected within the earth-centered framework that existed at that time.  It was also around this time that he invented a geometric and military compass.  Galileo sought a patron, and made overtures to the Cosimo family, but had to supplement his income by selling his compass to students along with a handbook on how to use it.  He also invented a primitive [[thermometer]] and a [[barometer]].
-== His telescope and astronomical discoveries ==
-In June or July of 1609, five years after his initial discovery, Galileo heard about the telescope, which had been invented in [[Netherlands|Holland]]. Without knowing the technical details of the construction of the device, he was able to create one for himself. Over time he continued to upgrade it. He found mountains on the Moon, viewed the phases of [[Venus]], and discovered four satellites around [[Jupiter]] as well as locating [[sunspots]].
-In 1610 [[Galileo]] used the newly invented [[telescope]] to observe [[Jupiter]] and discovered four smaller bodies revolving around it.
-[[NASA]] scientist Ron Baalke wrote
-{{cquote| Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. The next evening, these stars seemed to have moved the wrong way, which caught his attention. Galileo continued to observe the stars and Jupiter for the next week. On January 13, a fourth star appeared. After a few weeks, Galileo had observed that the four stars never left the vicinity of Jupiter and appeared to be carried along with the planet, and that they changed their position with respect to each other and Jupiter. Finally, Galileo determined that what he was observing were not stars, but planetary bodies that were in orbit around Jupiter. [http://www2.jpl.nasa.gov/galileo/ganymede/discovery.html]}}
-He published his finding in a paper titled "The Starry Messenger" which he dedicated to Grand Duke Cosimo II.  His discoveries and publication led him to be appointed as Grand Duke court mathematician, a position he had coveted.
-== The city fathers of Florence and the new bell ==
-As Galileo became more well known, he was commissioned by the city father's of [[Florence]] to find a way to cast a new bell for the town.  The local artisans had been unsuccessful, as the wooden mold for the bell's inner surface kept rising when molten metal was poured between it and the mold for the outer surface. Using [[Archimedes]] as his guide, Galileo explained that bodies must be heavier than the volume of liquid they displace or they will float to the surface.  This view went against [[Aristotle]] who had claimed that objects floated when they "pierced" the skin of a liquid and escaped from it. Based on what Galileo told them, the Florence bell-casters succeeded in their task by increasing the pressure on the inner mold.  Since Galileo had also recently shown that Aristotle was wrong about falling objects, he was walking on sensitive ground.<ref>''Christian History'', Issue 76, "Galileo and the Powers Above"</ref>
-== Advocacy of the Copernican system and conflict with Church authorities ==
-Until the sixteenth century, the prevailing view was that the [[Sun]], Moon, [[star]]s and [[planet]]s circled the [[Earth]] (the [[geocentrism|geocentric]] system, based on the second century work of [[Ptolemy]]). Puzzled astronomers noticed that [[Mars]], [[Jupiter]] and [[Saturn]] sometimes seemed to move backwards, but their motions were well within the predictions of Ptolemy's theory.  The moon was considered to have more freedom of movement.
-A Polish astronomer, Nicolaus [[Copernicus]] (1473-1543), published a model of the solar system ''De Revolutionibus'' in 1543, in which the earth and other planets circled the sun. The Catholic Church endorsed the book. The book’s preface (which was not written by Copernicus) argued that astronomical models have merit if they correctly predict observations, even if the underlying hypotheses cannot be proved.<ref>[http://webexhibits.org/calendars/year-text-Copernicus.html ''On the Revolutions'' - English translation.]</ref> The scientific evidence was inconclusive.
-However, ancient [[Greek]] thought was idolized since it was re-discovered several hundred years before, being viewed almost on par with the [[Bible]] itself. The Ptolemaic system was the prevailing view at the time. Initially it was not the theologians who balked at Galileo's ideas, but rather mathematicians at the University of [[Pisa]] who were so outraged that he challenged Aristotle that they refused to even look through his telescope at the stars. Galileo wrote a privately-circulated pamphlet which argued that the Bible should be interpreted in the light of increasing knowledge, and warning that scientific opinion should not be treated as an article of faith.  In this way he matched the great church father [[Saint Augustine]].  Quoting another of the early church fathers Galileo wrote <blockquote>''The intention of the Holy Ghost is to teach us how one goes to heaven, not how heaven goes.''</blockquote>
-In 1613 a [[Dominican]] friar, [[Tommaso Caccini]], got a hold of Galileo's writing and preached a sermon against him. A mangled version of Galileo's writing was sent to [[Rome]].  Galileo heard of this and sent the full version.  He was not terribly alarmed, knowing that many of the best minds in [[Italy]], including the [[Vatican]]'s mathematicians, were convinced on the heliocentric universe that his works had help to substantiate.  Caccini's Dominican superior was so embarrassed that he sent a letter of apology to Galileo.
-Caccini wasn't through, however, and gave an unsolicited deposition to the Inquisition about Galileo's views, which largely demonstrated his own ignorance on the subject.  Nevertheless, the theologians who were given the case ruled in a manner that was not pleasing to Galileo when it was handed down. Galileo was told by the Inquisition that he must only use Copernican concepts as a hypothesis for the sake of calculation, without claiming that they had been literally proven true. Because Galileo had overstated the scientific case for the heliocentric theory and given some dubious theological arguments, the Inquisition ruling decided that: 1) the immobility of the Sun at the center of the universe was absurd in philosophy and formally heretical, and that 2) the mobility of Earth was absurd in [[philosophy]] and at least erroneous in theology. <ref> [http://www.hps.cam.ac.uk/starry/galileo.html ''[[University of Cambridge]], Department of History and Philosophy of Science'' - Galileo Galilei]</ref> The following month the Church’s [[Index of Forbidden Books]] required that nine sentences in Copernicus's book be corrected.
-Looking back, it is hard to understand the decision, but in defense of the arbiters of that time, the view through Galileo's telescope was nothing like the quality of telescopes today.  To untrained laymen, it would be difficult to know what was being viewed.  Also, the concept of stellar parallax, a condition that had to exist if Galileo was right, could not be properly detected at the time. (Parallax is real, but due to the incredibly far distances of the stars in relationship to the earth's movement around the sun, it could not be detected until 1838, over 200 years later.)
-== Using the principle of falsifiability to improve the scientific method ==
-[[Image:Galileo....jpg|left|120px]]
-Galileo tested [[Aristotle]]'s theory that heavy objects fall faster than light ones and found it was a consequence of air resistance, not [[gravity]]. By making careful measurements he found he could use mathematics to measure the acceleration of gravity and predict the movements of [[pendulum]]s and tides.
-Galileo got approval from Rome to write his book ''Dialogue on the Tides'', which discussed both the Ptolemaic and Copernican hypotheses, as long as it discussed both systems and did not draw a conclusion that would make the heliocentric world view be viewed as fact instead of theory.  Rome changed the title to ''Dialogue on the Two Chief World Systems'' and it was published in Florence in 1632.  Unfortunately for Galileo, the work was not made to be evenhanded. Indeed, the Ptolemaic character, called 'Simplicius' often stumbled over his own errors and seemed quite foolish. Galileo had moved out of bounds and even his name 'Simplicius' seemed designed to embarrass the Church.  The Church felt they had made themselves clear. At a different time, the reaction might have been different, but it was in the middle of the [[30 years war]], the most deadly war in Europe ever fought between Catholics and Protestants, and embarrassing one side could result in the loss in life.  Galileo claimed approval by the Church for his entire work, and that was simply false.  It would be analogous today to someone speaking in the name of an organization in a way that embarrasses it, and the result is typically the same:  the person is promptly fired and, if the harm is serious, often prosecuted.  Put another way, Galileo's act was treasonous at a time of war.  The Catholic Church felt compelled at a time of crisis to clarify its authority.  At no time was there any claim of papal infallibility; this was a matter of misrepresentation of the Church's position.
-The Church officials, who felt Galileo had embarrassed them, found that Galileo had erred by advocating in the name of the Church that heliocentrism was scientifically proven.  This was not compatible with the Inquisition's 1616 ruling and what Galileo had recently been told. In 1633 Galileo was ordered to stand trial in Rome. Galileo could have left the Church but instead chose to submit voluntarily its authority and decision.  According to the terms of his sentence, renounced his [[thesis]] of his [[book]]. At first he was sentenced to life imprisonment, but this was immediately commuted to luxurious house arrest.  His book was burned, and the sentence against him was read aloud in public in every university. <ref>[http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761557587&pn=3 ''MSN Encarta'' - Galileo (p3)]</ref> Galileo went back to studying motion and mechanics in his private villa.  He received the Pope's personal blessing before he died, which is a rare honor.
-Galileo's theory of tides that he also promoted was proven to be false.
-==''Dialogues Concerning Two New Sciences''==
-Galileo’s last book, the 1638 work ''Dialogues Concerning Two New Sciences'', dealt with motion and mechanics. This work helped inspire [[Isaac Newton]] to create his theory of [[gravity]], which linked Galileo’s mathematics and physics to [[Johannes Kepler|Kepler’s]] laws of planetary movement.
-[[Image:Galileobones.jpg|right|thumb|200px|Galileo's drawing of how the dimensions of different-sized bones need to vary to make them equally strong in relation to their function]]
-In ''Two New Sciences,'' Galileo revealed a sophisticated understanding of engineering and what now would be called [[dimensional analysis]], the way in which the proportions of an engineering structure need to change as the size of the structure is scaled up. He applied this to [[biology]], explaining why the bones of a large animal need to be thicker in proportion to their size than those of smaller animals.
-In an age before stopwatches, Galileo was able to make quantitative observations of uniformly-accelerated motion, using his pulse as a time reference and watching the slow acceleration of objects moving down inclined planes.
-This book contains his famous discussion and thought experiment, in which he shows both by logic and by appeal to experiment that light and heavy objects fall at the same speed (contradicting Aristotle). One of his discussants says "But I, Simplicio, who have made the test can assure you that a cannon ball weighing one or two hundred pounds, or even more, will not reach the ground by as much as a span ahead of a musket ball weighing only half a pound, provided both are dropped from a height of 200 cubits."<ref>Crew, Henry and Alfonso de Salvio (1914), ''Dialogues Concerning Two New Sciences by Galileo Galilei,'' Northwestern University, 1939 reprint of 1914 Macmillan edition, p. 62</ref>.
-Another discussant points out that this result is logical, by positing a large stone that moves at a speed of eight and a smaller one which moves at a speed of four, and showing that this leads to a contradiction if the stones are tied together. Since the smaller stone tends to fall more slowly, it ought to retard the motion of the larger one, so the combination should fall more slowly than the large stone by itself. However, "the two stones when tied together make a stone larger than before," and hence ought to fall more quickly than the large stone by itself.
-It is interesting to see how Galileo was able to obtain quantitative results in physics before algebra and calculus were invented. The book uses the methods of geometry, and lays out "proofs" of physical relationships using a style and terminology similar to [[Euclid]]'s Elements.
-In 1741, a century after Galileo's death in January 1642, the dispute with the Catholic Church was finally settled officially when the Church under [[Pope Benedict XIV]] bid the [[Holy Office]] grant an imprimatur to the first edition of the <i>Complete Works of Galileo</i>.<ref>  [http://www.catholiceducation.org/articles/history/world/wh0005.html  The Galileo Affair]</ref>
-Stillman Drake of the [[University of Toronto]] [http://www.utpjournals.com/product/utq/701/galileo46.html] was for the last decades of his life the most original and important scholar to study this seventeenth-century physicist.<ref>[http://www.chass.utoronto.ca/imago/drake.html|The Stillman Drake Collection]</ref>
-==Charges of heresy and theological error==
-{{QuoteBox|The Holy Tribunal in Galileo's condemnation states: "The proposition that the sun is the center of the world and does not move from its place is absurd and false philosophically and formally heretical, because it is expressly contrary to the Holy Scripture.<br /><br />The proposition that the earth is not the center of the world and immovable, but that it moves, and also with a diurnal motion, is equally absurd and false philosophically, and theologically considered, at least erroneous in faith." <ref>Henderson, Thomas H., [http://www.christiananswers.net/q-eden/galileo.html What were Galileo's scientific and biblical conflicts with the Church?], quoting Janelle Rohr, editor, Science & Religion--Opposing Viewpoints (Greenhaven Press, 1988), p. 24.</ref>}}
-==Noteworthy Facts==
-<!-- These quotations need to be woven into the text of the article. -->
-<!--* "Early in 1616, Galileo was accused of being a heretic, a person who opposed Church teachings. Heresy was a crime for which people were sometimes sentenced to death. Galileo was cleared of charges of heresy, but was told that he should no longer publicly state his belief that Earth moved around the Sun."<ref name="nasabio"> [http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level2/galileo.html Galileo Galilei] - NASA bio</ref>-->
-*For his promotion of the Copernican view of the Solar System as though it were the Church's position, Galileo was accused by the Catholic Church of disobeying its authority and misrepresenting its position. This was a crime that was sometimes punishable by death, just as treason is so punished today. He was later cleared, but forbidden from publicly misrepresenting the Church's position.<ref name="nasabio"> [http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level2/galileo.html Galileo Galilei] - NASA bio</ref>.
-<!--* "In 1632, he published a book that stated, among other things, that the heliocentric theory of Copernicus was correct. Galileo was once again called before the Inquisition and this time was found guilty of heresy. Galileo was sentenced to life imprisonment in 1633."<ref name="nasabio" />-->
-*Galileo published a book in 1632 restating his belief in Copernicus theory. He was again called before the inquisition, this time being found guilty of publishing a book in the Church's name despite its disapproval. He was confined to house arrest, but never condemned<ref name="nasabio" />.
-<!--* "On 31 October 1992, 350 years after Galileo's death, Pope John Paul II gave an address on behalf of the Catholic Church in which he admitted that errors had been made by the theological advisors in the case of Galileo. He declared the Galileo case closed, but he did not admit that the Church was wrong to convict Galileo on a charge of heresy because of his belief that the Earth rotates round the sun." [http://www-history.mcs.st-and.ac.uk/Biographies/Galileo.html]  Both Protestant and Catholics at the time felt that the sun rotates around the Earth.-->
-*The Catholic church admitted that mistakes had been made in 1992. In a speech Pope John Paul II declared the Galileo case closed, but did not admit that the church was wrong on the charge of misrepresenting the Church view at the time he was convicted.<ref>[http://www-history.mcs.st-and.ac.uk/Biographies/Galileo.html]</ref>
-==External Links==
-*[http://www.relativitycalculator.com/Galileo.shtml &nbsp; Galileo Galilei - father of modern science according to Einstein]
-==Further reading==
-* Drake, Stillman. ''Galileo: Pioneer Scientist.'' (1990). 261 pp.
-* Drake, Stillman. ''Galileo.'' (1981). 100 pp.
-* Fantoli, Annibale. ''Galileo: For Copernicanism and for the Church.'' (1994). 540pp
-* Feldhay, Rivka. ''Galileo and the Church: Political Inquisition or Critical Dialogue?'' (1995). 303 pp.
-* Finocchiaro, Maurice A., ed. ''The Galileo Affair: A Documentary History.'' (1989). 382 pp. primary sources
-* Reston, James. ''Galileo: A Life.'' (1994). 319 pp., popular
-* Sharratt, Michael. ''Galileo: Decisive Innovator.'' (1994). 247 pp.
-== References ==
-<references />
-{{DEFAULTSORT: Galileo Galilei}}
-[[category:Physicists]]
-[[Category:Astronomers]]
-[[Category:Italian People]]
-[[category:Platonists]]

Difference between revisions of "Galileo Galilei"

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