Mostrar mensagens com a etiqueta Galileu Galilei. Mostrar todas as mensagens
Mostrar mensagens com a etiqueta Galileu Galilei. Mostrar todas as mensagens

quarta-feira, junho 22, 2022

A Inquisição condenou Galileu há 389 anos - e, no entanto, move-se...

Cristiano Banti's 1857 painting Galileo facing the Roman Inquisition
    
Galileo Galilei (Pisa, 15 February 1564 – Arcetri, 8 January 1642), was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy", the "father of modern physics", the "father of science" and "the Father of Modern Science".
His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.
Galileo's championing of heliocentrism was controversial within his lifetime, when most subscribed to either geocentrism or the Tychonic system. He met with opposition from astronomers, who doubted heliocentrism due to the absence of an observed stellar parallax. The matter was investigated by the Roman Inquisition in 1615, and they concluded that it could be supported as only a possibility, not an established fact. Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII and thus alienated him and the Jesuits, who had both supported Galileo up until this point. He was tried by the Inquisition, found "vehemently suspect of heresy", forced to recant, and spent the rest of his life under house arrest. It was while Galileo was under house arrest that he wrote one of his finest works, Two New Sciences, in which he summarised the work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials.
   
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Controversy over heliocentrism
Biblical references Psalm 93:1, 96:10, and 1 Chronicles 16:30 include text stating that "the world is firmly established, it cannot be moved." In the same manner, Psalm 104:5 says, "the Lord set the earth on its foundations; it can never be moved." Further, Ecclesiastes 1:5 states that "And the sun rises and sets and returns to its place."
Galileo defended heliocentrism, and claimed it was not contrary to those Scripture passages. He took Augustine's position on Scripture: not to take every passage literally, particularly when the scripture in question is a book of poetry and songs, not a book of instructions or history. He believed that the writers of the Scripture merely wrote from the perspective of the terrestrial world, from that vantage point that the sun does rise and set. Another way to put this is that the writers would have been writing from a phenomenological point of view, or style. So Galileo claimed that science did not contradict Scripture, as Scripture was discussing a different kind of "movement" of the earth, and not rotations.
By 1616 the attacks on the ideas of Copernicus had reached a head, and Galileo went to Rome to try to persuade Catholic Church authorities not to ban Copernicus' ideas. In the end, a decree of the Congregation of the Index was issued, declaring that the ideas that the Sun stood still and that the Earth moved were "false" and "altogether contrary to Holy Scripture", and suspending Copernicus's De Revolutionibus until it could be corrected. Acting on instructions from the Pope before the decree was issued, Cardinal Bellarmine informed Galileo that it was forthcoming, that the ideas it condemned could not be "defended or held", and ordered him to abandon them. Galileo promised to obey. Bellarmine's instruction did not prohibit Galileo from discussing heliocentrism as a mathematical fiction but was dangerously ambiguous as to whether he could treat it as a physical possibility. For the next several years Galileo stayed well away from the controversy. He revived his project of writing a book on the subject, encouraged by the election of Cardinal Maffeo Barberini as Pope Urban VIII in 1623. Barberini was a friend and admirer of Galileo, and had opposed the condemnation of Galileo in 1616. The book, Dialogue Concerning the Two Chief World Systems, was published in 1632, with formal authorization from the Inquisition and papal permission.
Dava Sobel explains that during this time, Urban had begun to fall more and more under the influence of court intrigue and problems of state. His friendship with Galileo began to take second place to his feelings of persecution and fear for his own life. At this low point in Urban's life, the problem of Galileo was presented to the pope by court insiders and enemies of Galileo. Coming on top of the recent claim by the then Spanish cardinal that Urban was soft on defending the church, he reacted out of anger and fear. This situation did not bode well for Galileo's defence of his book.
Earlier, Pope Urban VIII had personally asked Galileo to give arguments for and against heliocentrism in the book, and to be careful not to advocate heliocentrism. He made another request, that his own views on the matter be included in Galileo's book. Only the latter of those requests was fulfilled by Galileo. Whether unknowingly or deliberately, Simplicio, the defender of the Aristotelian Geocentric view in Dialogue Concerning the Two Chief World Systems, was often caught in his own errors and sometimes came across as a fool. Indeed, although Galileo states in the preface of his book that the character is named after a famous Aristotelian philosopher (Simplicius in Latin, Simplicio in Italian), the name "Simplicio" in Italian also has the connotation of "simpleton". This portrayal of Simplicio made Dialogue Concerning the Two Chief World Systems appear as an advocacy book: an attack on Aristotelian geocentrism and defence of the Copernican theory. Unfortunately for his relationship with the Pope, Galileo put the words of Urban VIII into the mouth of Simplicio. Most historians agree Galileo did not act out of malice and felt blindsided by the reaction to his book. However, the Pope did not take the suspected public ridicule lightly, nor the Copernican advocacy. Galileo had alienated one of his biggest and most powerful supporters, the Pope, and was called to Rome to defend his writings.
In September 1632, Galileo was ordered to come to Rome to stand trial. He finally arrived in February 1633 and was brought before inquisitor Vincenzo Maculani to be charged. Throughout his trial Galileo steadfastly maintained that since 1616 he had faithfully kept his promise not to hold any of the condemned opinions, and initially he denied even defending them. However, he was eventually persuaded to admit that, contrary to his true intention, a reader of his Dialogue could well have obtained the impression that it was intended to be a defence of Copernicanism. In view of Galileo's rather implausible denial that he had ever held Copernican ideas after 1616 or ever intended to defend them in the Dialogue, his final interrogation, in July 1633, concluded with his being threatened with torture if he did not tell the truth, but he maintained his denial despite the threat. The sentence of the Inquisition was delivered on June 22. It was in three essential parts:
  • Galileo was found "vehemently suspect of heresy", namely of having held the opinions that the Sun lies motionless at the centre of the universe, that the Earth is not at its centre and moves, and that one may hold and defend an opinion as probable after it has been declared contrary to Holy Scripture. He was required to "abjure, curse and detest" those opinions.
  • He was sentenced to formal imprisonment at the pleasure of the Inquisition. On the following day this was commuted to house arrest, which he remained under for the rest of his life.
  • His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future.
According to popular legend, after recanting his theory that the Earth moved around the Sun, Galileo allegedly muttered the rebellious phrase And yet it moves (italian: Eppur si muove) but there is no evidence that he actually said this or anything similar. The first account of the legend dates to a century after his death.
After a period with the friendly Ascanio Piccolomini (the Archbishop of Siena), Galileo was allowed to return to his villa at Arcetri near Florence in 1634, where he spent the remainder of his life under house arrest. Galileo was ordered to read the seven penitential psalms once a week for the next three years. However his daughter Maria Celeste relieved him of the burden after securing ecclesiastical permission to take it upon herself. It was while Galileo was under house arrest that he dedicated his time to one of his finest works, Two New Sciences. Here he summarised work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials. This book has received high praise from Albert Einstein. As a result of this work, Galileo is often called the "father of modern physics". He went completely blind in 1638 and was suffering from a painful hernia and insomnia, so he was permitted to travel to Florence for medical advice.
   

terça-feira, fevereiro 22, 2022

Um livro de Galileu acabou com a teoria geocêntrica há 390 anos

  
Diálogo sobre os dois principais sistemas do mundo (no original em italiano Dialogo sopra i due massimi sistemi del mondo) é um livro, publicado a 22 de fevereiro de 1632 e escrito por Galileu Galilei. Foi uma obra marcante da Revolução científica. Nele, Galileu utiliza três personagens, Salviati, Simplício e Sagredo, que debatem sobre Mecânica. O Diálogo é uma obra de combate, cujo objetivol era o de fazer rever o édito de 1616 da Inquisição romana que proibia o livro De revolutionibus, de Copérnico. Ao afirmar assim o caráter planetário da Terra, Galileu destrói os fundamentos antropocêntricos da visão tradicionalista cristã que defendia o geocentrismo. E, de facto, será condenado, em 1633, por esta obra, que inaugura a ciência moderna e redesenha o mapa da cultura ocidental, mostrar que a teoria heliocêntrica era verdadeira.
   

terça-feira, fevereiro 15, 2022

Galileu Galilei nasceu há 458 anos

     
Galileu Galilei (em italiano: Galileo Galilei; Pisa, 15 de fevereiro de 1564 - Florença, 8 de janeiro de 1642) foi um físico, matemático, astrónomo e filósofo italiano.
Galileu Galilei foi personalidade fundamental na revolução científica. Foi o mais velho dos sete filhos do alaudista Vincenzo Galilei e de Giulia Ammannati. Viveu a maior parte de sua vida em Pisa e em Florença, na época integrantes do Grão-Ducado da Toscana.
Galileu Galilei desenvolveu os primeiros estudos sistemáticos do movimento uniformemente acelerado e do movimento do pêndulo. Descobriu a lei dos corpos e enunciou o princípio da inércia e o conceito de referencial inercial, ideias precursoras da mecânica newtoniana. Galileu melhorou significativamente o telescópio refrator e com ele descobriu as manchas solares, as montanhas da Lua, as fases de Vénus, quatro dos satélites de Júpiter, os anéis de Saturno, as estrelas da Via Láctea. Estas descobertas contribuíram decisivamente na defesa do heliocentrismo. Contudo a principal contribuição de Galileu foi para o método científico, pois a ciência assentava numa metodologia aristotélica.
O físico desenvolveu ainda vários instrumentos como a balança hidrostática, um tipo de compasso geométrico que permitia medir ângulos e áreas, o termómetro de Galileu e o precursor do relógio de pêndulo. O método empírico, defendido por Galileu, constitui um corte com o método aristotélico mais abstrato utilizado nessa época, devido a este Galileu é considerado como o "pai da ciência moderna".
    

segunda-feira, janeiro 10, 2022

O astrónomo Simon Marius nasceu há 449 anos

  
Simon Marius (Gunzenhausen, 10 de janeiro de 1573Ansbach, 5 de janeiro de 1625) foi um astrónomo alemão.
Em 1614 Marius publicou a obra Mundus Iovalis, descrevendo o planeta Júpiter e as suas luas. Na obra, afirmou ter descoberto as quatro maiores luas de Júpiter dias antes de Galileu. Tal afirmação deu início a uma disputa com Galileu. Considera-se possível que Marius tenha descoberto as luas de Júpiter independentemente, mas pelo menos alguns dias depois que Galileu; se tal afirmação for verdadeira, Marius seria a única pessoa que observou as luas no período anterior à publicação das observações de Galileu. Independente desta questão, os nomes mitológicos pelos quais estas luas são conhecidas atualmente (Io, Europa, Ganímedes e Calisto) são aqueles que Marius escolheu.
Simon Marius também afirmava ser o descobridor da Nebulosa de Andrómeda, que na realidade já era conhecida desde a Idade Média por astrónomos árabes.

Ganimedes, o maior satélite do Sistema Solar, foi descoberto há 412 anos

 
Ganímedes é o principal satélite natural de Júpiter, o maior do Sistema Solar, sendo maior que o planeta Mercúrio em termos de tamanho (mas não de massa). Este gigantesco satélite orbita Júpiter a 1,070 milhões de quilómetros de distância.
Ganímedes foi descoberta em 1610 e é uma das quatro luas de Galileu, descobertas por Galileo Galilei na órbita de Júpiter, em suas observações feitas graças à invenção do telescópio. No entanto, Ganímedes é visível a olho nu, mas apenas em condições favoráveis e por aqueles com boa visão.

Mitologia
Tal como as outras três luas de Galileu, o nome de Ganímedes foi dado por Simon Marius com o nome de amores de Zeus (Júpiter para os romanos), sendo o único nome masculino das quatro.
Na mitologia, Ganímedes tinha como função servir néctar e ambrosia aos deuses. Antes de adquirir a imortalidade era um jovem famoso pela sua beleza. Zeus (Júpiter) apaixonou-se por ele e este transformou-se em águia para raptá-lo, e assim levou Ganímedes até aos céus nas suas garras.

Descoberta e exploração
Ganímedes foi descoberto a 11 de janeiro de 1610 por Galileu Galilei. Alguns vêem Simon Marius como o seu descobridor.
Os astrónomos, baseados em observações feitas a partir da superfície da Terra, tinham apenas poucas informações sobre Ganimedes, mesmo com o uso dos melhores telescópios de meados do século XX. Foi só quando as sondas Pioneer 10 e Pioneer 11 chegaram a Júpiter em 1973 e em 1974, respectivamente, que se conseguiu obter as primeiras imagens mais detalhadas das grandes luas de Júpiter.
As Pioneer conseguiram captar duas boas imagens de Ganímedes. Estas imagens mostravam pouca variação de cor, mas revelaram uma variação substancial de albedo.
Em 1979 as sondas Voyager alcançam Júpiter. As imagens da Voyager mostraram que Ganímedes tinha dois tipos de terrenos distintos: uma parte do globo é coberta por crateras, a outra por sulcos, o que revelou que a superfície gelada poderia sofrer processos tectónicos globais.
As Voyager foram as sondas que descobriram que Ganímedes era, na verdade, o maior satélite do Sistema Solar, e não Titã, satélite de Saturno, como se pensava até então. Isto só foi possível determinar quando as Voyager chegaram a Titã e descobriram que esta tinha uma atmosfera bastante densa que lhe dava aspecto de ser maior.
Devido ao seu tamanho e características, Ganímedes também entra para os contos de ficção científica através da imaginação de vários autores; de destacar o livro (Farmer in the Sky) de Robert Heinlein, em que Ganímedes é terraformado e colonizado por seres humanos. Em (2061: Odisseia Três) de Arthur C. Clarke, Ganímedes é aquecido pelo novo sol Lúcifer e contém um grande lago equatorial e é o centro da colonização humana no sistema joviano.
Na década de 80 uma equipe de astrónomos indianos e norte-americanos num observatório na Indonésia detectaram uma atmosfera ténue à volta de Ganímedes durante uma ocultação quando Júpiter passou em frente de uma estrela. Mais recentemente, o Telescópio Espacial Hubble, detectou que essa atmosfera era composta de oxigénio, tal como a atmosfera encontrada em Europa.
Em 7 de dezembro de 1995, a sonda Galileu chegou a Júpiter numa viagem contínua pelo planeta e suas luas durante oito anos. Logo na primeira aproximação a Ganímedes, a Galileu descobriu que Ganímedes tinha o seu próprio campo magnético imerso no campo magnético gigantesco de Júpiter.


Geologia planetária
Ganímedes possui um diâmetro médio de 5262,4 km; sendo um pouco maior que o planeta Mercúrio.
A densidade de Ganímedes é de 1,942 kg/m³. A baixa densidade deve-se à elevada percentagem de gelos com alguns silicatos de material primordial e de impacto proveniente do espaço.
Ganímedes é composto por rocha de silicatos e gelo de água, com a crusta de gelo flutuando sobre um manto lamacento que pode conter uma camada de água líquida. A sonda Galileu indicou que a estrutura de Ganímedes divide-se em três camadas: um pequeno núcleo de ferro ou de ferro e enxofre derretido rodeado por um manto rochoso de silicatos com uma capa de gelo por cima. Este núcleo metálico sugere um elevado grau de aquecimento no passado de Ganímedes do que se julgava. De facto, Ganímedes pode ser semelhante a Io, mas com uma capa externa adicional de gelo.
A crusta gelada divide-se em placas tectónicas. Estas características sugerem que o interior terá sido mais activo que hoje, com muito mais calor no manto.
O campo magnético de Ganímedes está inserido no campo magnético gigantesco de Júpiter. Provavelmente, este é criado como o da Terra, resultando do movimento de material condutor no seu interior. Pensa-se que este material condutor possa ser uma camada de água líquida com uma concentração elevada de sal, ou que possa ser originado no núcleo metálico de Ganímedes.
   

sábado, janeiro 08, 2022

Poema adequado à data...


 

Poema para Galileo

 

Estou olhando o teu retrato, meu velho pisano,
aquele teu retrato que toda a gente conhece,
em que a tua bela cabeça desabrocha e floresce
sobre um modesto cabeção de pano.
Aquele retrato da Galeria dos Ofícios da tua velha Florença.
(Não, não, Galileo! Eu não disse Santo Ofício.
Disse Galeria dos Ofícios.)
Aquele retrato da Galeria dos Ofícios da requintada Florença.


Lembras-te? A Ponte Vecchio, a Loggia, a Piazza della Signoria…
Eu sei… eu sei…
As margens doces do Arno às horas pardas da melancolia.
Ai que saudade, Galileo Galilei!


Olha. Sabes? Lá em Florença
está guardado um dedo da tua mão direita num relicário.
Palavra de honra que está!
As voltas que o mundo dá!
Se calhar até há gente que pensa
que entraste no calendário.


Eu queria agradecer-te, Galileo,
a inteligência das coisas que me deste.
Eu,
e quantos milhões de homens como eu
a quem tu esclareceste,
ia jurar- que disparate, Galileo!
- e jurava a pés juntos e apostava a cabeça
sem a menor hesitação-
que os corpos caem tanto mais depressa
quanto mais pesados são.


Pois não é evidente, Galileo?
Quem acredita que um penedo caía
com a mesma rapidez que um botão de camisa ou que um seixo da praia?
Esta era a inteligência que Deus nos deu.


Estava agora a lembrar-me, Galileo,
daquela cena em que tu estavas sentado num escabelo
e tinhas à tua frente
um friso de homens doutos, hirtos, de toga e de capelo
a olharem-te severamente.
Estavam todos a ralhar contigo,
que parecia impossível que um homem da tua idade
e da tua condição,
se tivesse tornado num perigo
para a Humanidade
e para a Civilização.
Tu, embaraçado e comprometido, em silêncio mordiscavas os lábios,
e percorrias, cheio de piedade,
os rostos impenetráveis daquela fila de sábios.


Teus olhos habituados à observação dos satélites e das estrelas,
desceram lá das suas alturas
e poisaram, como aves aturdidas- parece-me que estou a vê-las -,
nas faces grávidas daquelas reverendíssimas criaturas.
E tu foste dizendo a tudo que sim, que sim senhor, que era tudo tal qual
conforme suas eminências desejavam,
e dirias que o Sol era quadrado e a Lua pentagonal
e que os astros bailavam e entoavam
à meia-noite louvores à harmonia universal.
E juraste que nunca mais repetirias
nem a ti mesmo, na própria intimidade do teu pensamento, livre e calma,
aquelas abomináveis heresias
que ensinavas e descrevias
para eterna perdição da tua alma.
Ai Galileo!
Mal sabem os teus doutos juízes, grandes senhores deste pequeno mundo
que assim mesmo, empertigados nos seus cadeirões de braços,
andavam a correr e a rolar pelos espaços
à razão de trinta quilómetros por segundo.
Tu é que sabias, Galileo Galilei.


Por isso eram teus olhos misericordiosos,
por isso era teu coração cheio de piedade,
piedade pelos homens que não precisam de sofrer, homens ditosos
a quem Deus dispensou de buscar a verdade.
Por isso estoicamente, mansamente,
resististe a todas as torturas,
a todas as angústias, a todos os contratempos,
enquanto eles, do alto incessível das suas alturas,
foram caindo,
caindo,
caindo,
caindo,
caindo sempre,
e sempre,
ininterruptamente,
na razão directa do quadrado dos tempos.

    
 
in Linhas de Força (1967) - António Gedeão

Galileu morreu há 380 anos

  
Galileo Galilei (Pisa, 15 February 1564 – Arcetri, 8 January 1642), was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy", the "father of modern physics", the "father of science" and "the Father of Modern Science".
His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.
Galileo's championing of heliocentrism was controversial within his lifetime, when most subscribed to either geocentrism or the Tychonic system. He met with opposition from astronomers, who doubted heliocentrism due to the absence of an observed stellar parallax. The matter was investigated by the Roman Inquisition in 1615, and they concluded that it could be supported as only a possibility, not an established fact. Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII and thus alienated him and the Jesuits, who had both supported Galileo up until this point. He was tried by the Inquisition, found "vehemently suspect of heresy", forced to recant, and spent the rest of his life under house arrest. It was while Galileo was under house arrest that he wrote one of his finest works, Two New Sciences, in which he summarised the work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials.
   
(...)
  
Cristiano Banti's 1857 painting Galileo facing the Roman Inquisition
   
Controversy over heliocentrism
Biblical references Psalm 93:1, 96:10, and 1 Chronicles 16:30 include text stating that "the world is firmly established, it cannot be moved." In the same manner, Psalm 104:5 says, "the Lord set the earth on its foundations; it can never be moved." Further, Ecclesiastes 1:5 states that "And the sun rises and sets and returns to its place."
Galileo defended heliocentrism, and claimed it was not contrary to those Scripture passages. He took Augustine's position on Scripture: not to take every passage literally, particularly when the scripture in question is a book of poetry and songs, not a book of instructions or history. He believed that the writers of the Scripture merely wrote from the perspective of the terrestrial world, from that vantage point that the sun does rise and set. Another way to put this is that the writers would have been writing from a phenomenological point of view, or style. So Galileo claimed that science did not contradict Scripture, as Scripture was discussing a different kind of "movement" of the earth, and not rotations.
By 1616 the attacks on the ideas of Copernicus had reached a head, and Galileo went to Rome to try to persuade Catholic Church authorities not to ban Copernicus' ideas. In the end, a decree of the Congregation of the Index was issued, declaring that the ideas that the Sun stood still and that the Earth moved were "false" and "altogether contrary to Holy Scripture", and suspending Copernicus's De Revolutionibus until it could be corrected. Acting on instructions from the Pope before the decree was issued, Cardinal Bellarmine informed Galileo that it was forthcoming, that the ideas it condemned could not be "defended or held", and ordered him to abandon them. Galileo promised to obey. Bellarmine's instruction did not prohibit Galileo from discussing heliocentrism as a mathematical fiction but was dangerously ambiguous as to whether he could treat it as a physical possibility. For the next several years Galileo stayed well away from the controversy. He revived his project of writing a book on the subject, encouraged by the election of Cardinal Maffeo Barberini as Pope Urban VIII in 1623. Barberini was a friend and admirer of Galileo, and had opposed the condemnation of Galileo in 1616. The book, Dialogue Concerning the Two Chief World Systems, was published in 1632, with formal authorization from the Inquisition and papal permission.
Dava Sobel explains that during this time, Urban had begun to fall more and more under the influence of court intrigue and problems of state. His friendship with Galileo began to take second place to his feelings of persecution and fear for his own life. At this low point in Urban's life, the problem of Galileo was presented to the pope by court insiders and enemies of Galileo. Coming on top of the recent claim by the then Spanish cardinal that Urban was soft on defending the church, he reacted out of anger and fear. This situation did not bode well for Galileo's defence of his book.
Earlier, Pope Urban VIII had personally asked Galileo to give arguments for and against heliocentrism in the book, and to be careful not to advocate heliocentrism. He made another request, that his own views on the matter be included in Galileo's book. Only the latter of those requests was fulfilled by Galileo. Whether unknowingly or deliberately, Simplicio, the defender of the Aristotelian Geocentric view in Dialogue Concerning the Two Chief World Systems, was often caught in his own errors and sometimes came across as a fool. Indeed, although Galileo states in the preface of his book that the character is named after a famous Aristotelian philosopher (Simplicius in Latin, Simplicio in Italian), the name "Simplicio" in Italian also has the connotation of "simpleton". This portrayal of Simplicio made Dialogue Concerning the Two Chief World Systems appear as an advocacy book: an attack on Aristotelian geocentrism and defence of the Copernican theory. Unfortunately for his relationship with the Pope, Galileo put the words of Urban VIII into the mouth of Simplicio. Most historians agree Galileo did not act out of malice and felt blindsided by the reaction to his book. However, the Pope did not take the suspected public ridicule lightly, nor the Copernican advocacy. Galileo had alienated one of his biggest and most powerful supporters, the Pope, and was called to Rome to defend his writings.
In September 1632, Galileo was ordered to come to Rome to stand trial. He finally arrived in February 1633 and was brought before inquisitor Vincenzo Maculani to be charged. Throughout his trial Galileo steadfastly maintained that since 1616 he had faithfully kept his promise not to hold any of the condemned opinions, and initially he denied even defending them. However, he was eventually persuaded to admit that, contrary to his true intention, a reader of his Dialogue could well have obtained the impression that it was intended to be a defence of Copernicanism. In view of Galileo's rather implausible denial that he had ever held Copernican ideas after 1616 or ever intended to defend them in the Dialogue, his final interrogation, in July 1633, concluded with his being threatened with torture if he did not tell the truth, but he maintained his denial despite the threat. The sentence of the Inquisition was delivered on June 22. It was in three essential parts:
  • Galileo was found "vehemently suspect of heresy", namely of having held the opinions that the Sun lies motionless at the centre of the universe, that the Earth is not at its centre and moves, and that one may hold and defend an opinion as probable after it has been declared contrary to Holy Scripture. He was required to "abjure, curse and detest" those opinions.
  • He was sentenced to formal imprisonment at the pleasure of the Inquisition. On the following day this was commuted to house arrest, which he remained under for the rest of his life.
  • His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future.
According to popular legend, after recanting his theory that the Earth moved around the Sun, Galileo allegedly muttered the rebellious phrase And yet it moves (italian: Eppur si muove) but there is no evidence that he actually said this or anything similar. The first account of the legend dates to a century after his death.
After a period with the friendly Ascanio Piccolomini (the Archbishop of Siena), Galileo was allowed to return to his villa at Arcetri near Florence in 1634, where he spent the remainder of his life under house arrest. Galileo was ordered to read the seven penitential psalms once a week for the next three years. However his daughter Maria Celeste relieved him of the burden after securing ecclesiastical permission to take it upon herself. It was while Galileo was under house arrest that he dedicated his time to one of his finest works, Two New Sciences. Here he summarised work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials. This book has received high praise from Albert Einstein. As a result of this work, Galileo is often called the "father of modern physics". He went completely blind in 1638 and was suffering from a painful hernia and insomnia, so he was permitted to travel to Florence for medical advice.
 

terça-feira, junho 22, 2021

Eppur si muove - a Inquisição condenou Galileu há 388 anos

  
Galileo Galilei (Pisa, 15 February 1564 – Arcetri, 8 January 1642), was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy", the "father of modern physics", the "father of science" and "the Father of Modern Science".
His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.
Galileo's championing of heliocentrism was controversial within his lifetime, when most subscribed to either geocentrism or the Tychonic system. He met with opposition from astronomers, who doubted heliocentrism due to the absence of an observed stellar parallax. The matter was investigated by the Roman Inquisition in 1615, and they concluded that it could be supported as only a possibility, not an established fact. Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII and thus alienated him and the Jesuits, who had both supported Galileo up until this point. He was tried by the Inquisition, found "vehemently suspect of heresy", forced to recant, and spent the rest of his life under house arrest. It was while Galileo was under house arrest that he wrote one of his finest works, Two New Sciences, in which he summarised the work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials.
   
(...)
  
Cristiano Banti's 1857 painting Galileo facing the Roman Inquisition
   
Controversy over heliocentrism
Biblical references Psalm 93:1, 96:10, and 1 Chronicles 16:30 include text stating that "the world is firmly established, it cannot be moved." In the same manner, Psalm 104:5 says, "the Lord set the earth on its foundations; it can never be moved." Further, Ecclesiastes 1:5 states that "And the sun rises and sets and returns to its place."
Galileo defended heliocentrism, and claimed it was not contrary to those Scripture passages. He took Augustine's position on Scripture: not to take every passage literally, particularly when the scripture in question is a book of poetry and songs, not a book of instructions or history. He believed that the writers of the Scripture merely wrote from the perspective of the terrestrial world, from that vantage point that the sun does rise and set. Another way to put this is that the writers would have been writing from a phenomenological point of view, or style. So Galileo claimed that science did not contradict Scripture, as Scripture was discussing a different kind of "movement" of the earth, and not rotations.
By 1616 the attacks on the ideas of Copernicus had reached a head, and Galileo went to Rome to try to persuade Catholic Church authorities not to ban Copernicus' ideas. In the end, a decree of the Congregation of the Index was issued, declaring that the ideas that the Sun stood still and that the Earth moved were "false" and "altogether contrary to Holy Scripture", and suspending Copernicus's De Revolutionibus until it could be corrected. Acting on instructions from the Pope before the decree was issued, Cardinal Bellarmine informed Galileo that it was forthcoming, that the ideas it condemned could not be "defended or held", and ordered him to abandon them. Galileo promised to obey. Bellarmine's instruction did not prohibit Galileo from discussing heliocentrism as a mathematical fiction but was dangerously ambiguous as to whether he could treat it as a physical possibility. For the next several years Galileo stayed well away from the controversy. He revived his project of writing a book on the subject, encouraged by the election of Cardinal Maffeo Barberini as Pope Urban VIII in 1623. Barberini was a friend and admirer of Galileo, and had opposed the condemnation of Galileo in 1616. The book, Dialogue Concerning the Two Chief World Systems, was published in 1632, with formal authorization from the Inquisition and papal permission.
Dava Sobel explains that during this time, Urban had begun to fall more and more under the influence of court intrigue and problems of state. His friendship with Galileo began to take second place to his feelings of persecution and fear for his own life. At this low point in Urban's life, the problem of Galileo was presented to the pope by court insiders and enemies of Galileo. Coming on top of the recent claim by the then Spanish cardinal that Urban was soft on defending the church, he reacted out of anger and fear. This situation did not bode well for Galileo's defence of his book.
Earlier, Pope Urban VIII had personally asked Galileo to give arguments for and against heliocentrism in the book, and to be careful not to advocate heliocentrism. He made another request, that his own views on the matter be included in Galileo's book. Only the latter of those requests was fulfilled by Galileo. Whether unknowingly or deliberately, Simplicio, the defender of the Aristotelian Geocentric view in Dialogue Concerning the Two Chief World Systems, was often caught in his own errors and sometimes came across as a fool. Indeed, although Galileo states in the preface of his book that the character is named after a famous Aristotelian philosopher (Simplicius in Latin, Simplicio in Italian), the name "Simplicio" in Italian also has the connotation of "simpleton". This portrayal of Simplicio made Dialogue Concerning the Two Chief World Systems appear as an advocacy book: an attack on Aristotelian geocentrism and defence of the Copernican theory. Unfortunately for his relationship with the Pope, Galileo put the words of Urban VIII into the mouth of Simplicio. Most historians agree Galileo did not act out of malice and felt blindsided by the reaction to his book. However, the Pope did not take the suspected public ridicule lightly, nor the Copernican advocacy. Galileo had alienated one of his biggest and most powerful supporters, the Pope, and was called to Rome to defend his writings.
In September 1632, Galileo was ordered to come to Rome to stand trial. He finally arrived in February 1633 and was brought before inquisitor Vincenzo Maculani to be charged. Throughout his trial Galileo steadfastly maintained that since 1616 he had faithfully kept his promise not to hold any of the condemned opinions, and initially he denied even defending them. However, he was eventually persuaded to admit that, contrary to his true intention, a reader of his Dialogue could well have obtained the impression that it was intended to be a defence of Copernicanism. In view of Galileo's rather implausible denial that he had ever held Copernican ideas after 1616 or ever intended to defend them in the Dialogue, his final interrogation, in July 1633, concluded with his being threatened with torture if he did not tell the truth, but he maintained his denial despite the threat. The sentence of the Inquisition was delivered on June 22. It was in three essential parts:
  • Galileo was found "vehemently suspect of heresy", namely of having held the opinions that the Sun lies motionless at the centre of the universe, that the Earth is not at its centre and moves, and that one may hold and defend an opinion as probable after it has been declared contrary to Holy Scripture. He was required to "abjure, curse and detest" those opinions.
  • He was sentenced to formal imprisonment at the pleasure of the Inquisition. On the following day this was commuted to house arrest, which he remained under for the rest of his life.
  • His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future.
According to popular legend, after recanting his theory that the Earth moved around the Sun, Galileo allegedly muttered the rebellious phrase And yet it moves (italian: Eppur si muove) but there is no evidence that he actually said this or anything similar. The first account of the legend dates to a century after his death.
After a period with the friendly Ascanio Piccolomini (the Archbishop of Siena), Galileo was allowed to return to his villa at Arcetri near Florence in 1634, where he spent the remainder of his life under house arrest. Galileo was ordered to read the seven penitential psalms once a week for the next three years. However his daughter Maria Celeste relieved him of the burden after securing ecclesiastical permission to take it upon herself. It was while Galileo was under house arrest that he dedicated his time to one of his finest works, Two New Sciences. Here he summarised work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials. This book has received high praise from Albert Einstein. As a result of this work, Galileo is often called the "father of modern physics". He went completely blind in 1638 and was suffering from a painful hernia and insomnia, so he was permitted to travel to Florence for medical advice.
   

segunda-feira, fevereiro 22, 2021

Um livro de Galileu rebentou com a teoria geocêntrica há 389 anos

  
Diálogo sobre os dois principais sistemas do mundo (no original em italiano Dialogo sopra i due massimi sistemi del mondo) é um livro, publicado a 22 de fevereiro de 1632 e escrito por Galileu Galilei. Foi uma obra marcante da Revolução científica. Nele, Galileu utiliza três personagens, Salviati, Simplício e Sagredo, que debatem sobre Mecânica. O Diálogo é uma obra de combate, cujo objetivol era o de fazer rever o édito de 1616 da Inquisição romana que proibia o livro De revolutionibus, de Copérnico. Ao afirmar assim o caráter planetário da Terra, Galileu destrói os fundamentos antropocêntricos da visão tradicionalista cristã que defendia o geocentrismo. E, de facto, será condenado, em 1633, por esta obra, que inaugura a ciência moderna e redesenha o mapa da cultura ocidental, mostrar que a teoria heliocêntrica era verdadeira.
   

segunda-feira, fevereiro 15, 2021

Galileu Galilei nasceu há 457 anos

   
Galileu Galilei (em italiano: Galileo Galilei; Pisa, 15 de fevereiro de 1564 - Florença, 8 de janeiro de 1642) foi um físico, matemático, astrónomo e filósofo italiano.
Galileu Galilei foi personalidade fundamental na revolução científica. Foi o mais velho dos sete filhos do alaudista Vincenzo Galilei e de Giulia Ammannati. Viveu a maior parte de sua vida em Pisa e em Florença, na época integrantes do Grão-Ducado da Toscana.
Galileu Galilei desenvolveu os primeiros estudos sistemáticos do movimento uniformemente acelerado e do movimento do pêndulo. Descobriu a lei dos corpos e enunciou o princípio da inércia e o conceito de referencial inercial, ideias precursoras da mecânica newtoniana. Galileu melhorou significativamente o telescópio refrator e com ele descobriu as manchas solares, as montanhas da Lua, as fases de Vénus, quatro dos satélites de Júpiter, os anéis de Saturno, as estrelas da Via Láctea. Estas descobertas contribuíram decisivamente na defesa do heliocentrismo. Contudo a principal contribuição de Galileu foi para o método científico, pois a ciência assentava numa metodologia aristotélica.
O físico desenvolveu ainda vários instrumentos como a balança hidrostática, um tipo de compasso geométrico que permitia medir ângulos e áreas, o termómetro de Galileu e o precursor do relógio de pêndulo. O método empírico, defendido por Galileu, constitui um corte com o método aristotélico mais abstrato utilizado nessa época, devido a este Galileu é considerado como o "pai da ciência moderna".
    

segunda-feira, janeiro 11, 2021

Galileu descobriu Ganimedes , o maior satélite do Sistema Solar, há 411 anos

 
Ganimedes é o principal satélite natural de Júpiter, o maior do Sistema Solar, sendo maior que o planeta Mercúrio em termos de tamanho (mas não de massa). Este gigantesco satélite orbita Júpiter a 1,070 milhões de quilómetros de distância.
Ganímedes foi descoberta em 1610 e é uma das quatro luas de Galileu, descobertas por Galileo Galilei na órbita de Júpiter, em suas observações feitas graças à invenção do telescópio. No entanto, Ganímedes é visível a olho nu, mas apenas em condições favoráveis e por aqueles com boa visão.

Mitologia
Tal como as outras três luas de Galileu, o nome de Ganímedes foi dado por Simon Marius com o nome de amores de Zeus (Júpiter para os romanos), sendo o único nome masculino das quatro.
Na mitologia, Ganímedes tinha como função servir néctar e ambrosia aos deuses. Antes de adquirir a imortalidade era um jovem famoso pela sua beleza. Zeus (Júpiter) apaixonou-se por ele e este transformou-se em águia para raptá-lo, e assim levou Ganímedes até aos céus nas suas garras.

Descoberta e exploração
Ganímedes foi descoberto a 11 de janeiro de 1610 por Galileu Galilei. Alguns vêem Simon Marius como o seu descobridor.
Os astrónomos, baseados em observações feitas a partir da superfície da Terra, tinham apenas poucas informações sobre Ganimedes, mesmo com o uso dos melhores telescópios de meados do século XX. Foi só quando as sondas Pioneer 10 e Pioneer 11 chegaram a Júpiter em 1973 e em 1974, respectivamente, que se conseguiu obter as primeiras imagens mais detalhadas das grandes luas de Júpiter.
As Pioneer conseguiram captar duas boas imagens de Ganímedes. Estas imagens mostravam pouca variação de cor, mas revelaram uma variação substancial de albedo.
Em 1979 as sondas Voyager alcançam Júpiter. As imagens da Voyager mostraram que Ganímedes tinha dois tipos de terrenos distintos: uma parte do globo é coberta por crateras, a outra por sulcos, o que revelou que a superfície gelada poderia sofrer processos tectónicos globais.
As Voyager foram as sondas que descobriram que Ganímedes era, na verdade, o maior satélite do Sistema Solar, e não Titã, satélite de Saturno, como se pensava até então. Isto só foi possível determinar quando as Voyager chegaram a Titã e descobriram que esta tinha uma atmosfera bastante densa que lhe dava aspecto de ser maior.
Devido ao seu tamanho e características, Ganímedes também entra para os contos de ficção científica através da imaginação de vários autores; de destacar o livro (Farmer in the Sky) de Robert Heinlein, em que Ganímedes é terraformado e colonizado por seres humanos. Em (2061: Odisseia Três) de Arthur C. Clarke, Ganímedes é aquecido pelo novo sol Lúcifer e contém um grande lago equatorial e é o centro da colonização humana no sistema joviano.
Na década de 80 uma equipe de astrónomos indianos e norte-americanos num observatório na Indonésia detectaram uma atmosfera ténue à volta de Ganímedes durante uma ocultação quando Júpiter passou em frente de uma estrela. Mais recentemente, o Telescópio Espacial Hubble, detectou que essa atmosfera era composta de oxigénio, tal como a atmosfera encontrada em Europa.
Em 7 de dezembro de 1995, a sonda Galileu chegou a Júpiter numa viagem contínua pelo planeta e suas luas durante oito anos. Logo na primeira aproximação a Ganímedes, a Galileu descobriu que Ganímedes tinha o seu próprio campo magnético imerso no campo magnético gigantesco de Júpiter.


Geologia planetária
Ganímedes possui um diâmetro médio de 5262,4 km; sendo um pouco maior que o planeta Mercúrio.
A densidade de Ganímedes é de 1,942 kg/m³. A baixa densidade deve-se à elevada percentagem de gelos com alguns silicatos de material primordial e de impacto proveniente do espaço.
Ganímedes é composto por rocha de silicatos e gelo de água, com a crusta de gelo flutuando sobre um manto lamacento que pode conter uma camada de água líquida. A sonda Galileu indicou que a estrutura de Ganímedes divide-se em três camadas: um pequeno núcleo de ferro ou de ferro e enxofre derretido rodeado por um manto rochoso de silicatos com uma capa de gelo por cima. Este núcleo metálico sugere um elevado grau de aquecimento no passado de Ganímedes do que se julgava. De facto, Ganímedes pode ser semelhante a Io, mas com uma capa externa adicional de gelo.
A crusta gelada divide-se em placas tectónicas. Estas características sugerem que o interior terá sido mais activo que hoje, com muito mais calor no manto.
O campo magnético de Ganímedes está inserido no campo magnético gigantesco de Júpiter. Provavelmente, este é criado como o da Terra, resultando do movimento de material condutor no seu interior. Pensa-se que este material condutor possa ser uma camada de água líquida com uma concentração elevada de sal, ou que possa ser originado no núcleo metálico de Ganímedes.