Biography of Galileo Galilei (1564-1642)

Italian mathematician. It can be counted among the greatest scientists of all time, and as the most romantic figure of science. Born in Pisa on February 15, 1564 and died on January 8, 1642, son of a musician, he/she was also, as well as artist and writer. He/She studied first in Florence and later in Pisa. He/She began his career college in medicine, but then abandoned it to devote himself to research in the field of physics and mathematics. In 1589 was Professor of mathematics at the University of Pisa, with 25 years. It showed experimentally that fall bass speed was independent of your weight, so that the fall of two bodies in the same shape and volume but of different weight, dejados left dropped from the same height, occurs at the same time. So did slide areas downhill by the smooth surface of planes inclined at different angle of inclination (and wasn't with the release of bodies of different weight, from the leaning tower of Pisa, as I had thought for a long time).

Galileo Galilei.

Its not astronomical finds most remarkable include of the pendular movement (which began to think, according to the well known story, while observing a lamp that ranged in the Cathedral of Pisa), and the laws of the accelerated movement.

The work which earned him the title of father of the physical mathematical, was Discorsi e dimostrazioni matematiche, intorno a due nuove scienze attinenti the meccanica (speeches and demonstrations around two new related to the mechanical Sciences), written with the help of his disciple Torricelli, describing the results of his research on mechanics. Galileo created two new sciences now known as Dynamics and strength of materials.

In 1591 he/she moved to teach at the University of Padua, and then to Florence (1610). In both places Galileo was mainly devoted to astronomy. In 1609, having heard of large instruments manufactured in Holland, he/she built the first telescope, instrument capable of expanding objects about fifteen times, constituted by a convex lens coupled to a concave eyepiece. With him, in 1610, Galileo first observed the mountain elevations moles, as well as the four older satellites in orbit around Jupiter, baptized by him as planets mediceos, in honour of the illustrious Florentine family that protected it. He/She also made many other discoveries, observed numerous stars of weak luminosity, the phases of Venus and the structure of Saturn and sunspots, and published their results in the sidereal Messenger, masterpiece of Galileo. The observations of Galileo revolutionized astronomy, inducing a significant number of followers to procure a telescope, to personally verify their checks, which resulted in many discoveries. By what may be deemed, to Galileo, as the founder of modern astronomy, and more generally, as the introducer of the experimental method in scientific research. In addition to its outstanding results as a physicist and astronomer, the importance of Galileo is precisely in having created a new scientific mentality, whose bases are still ours.

He devoted himself intensely to astronomy until the year 1633, which was condemned ecclesiastically, threatened by the tribunal of the Inquisition to torture chamber if not he/she recant his ideas; It was the work, published in Florence in 1632, dialogues on the two highest world systems Ptolemaic and Copernican, which would cause him the condemnation of the Church and the prohibition to astronomy. Deeply convinced of the accuracy of the model of Copernicus (published in the year 1543 in his work of revolutlonibus orbium coelestium), who had claimed that the Sun and not the Earth was at the center of the universe, and that the Earth moved around the Sun like the other planets, Galileo went ahead with this thought, until he/she became an uphill battle for this truly revolutionary statementthat it destroyed the geocentric system of Ptolemy, embraced and tenaciously held by the official science, and above all, by the Church. However, the controversy with the ecclesiastical authorities had expressed many years earlier, already with his work the Messenger sidereal, and later with other works, in which expressing the results of his discoveries, was destroying the geocentric conception of the universe. At 69 years of age, was sentenced to house arrest of for life, and retired to his home in Arcetri, near Florence (where would die nine years later, the same year of the birth of Newton).

In honor to Galileo, named the unit of acceleration gal. The miligal is used by the Geophysics as a measurement of change in regional acceleration due to gravity.


Galileo can be considered as the founder of modern science, because he/she did wake up to the human intelligence of an uncritical acceptance of the authority of Aristotle, and traced the lines of an experimental method in which sensitive experience and reason came to be United in the common effort of research. It showed itself the validity and the effectiveness of innovative of this method with the experimental theories proposed verification and the construction of useful instruments to knowledge and ingenuity of the men. In particular, Galileo, especially with the Discorsi e dimostrazioni matematiche intorno a due nuovescienze attinenti alla meccanica ed ai movimenti localli, is universally recognized as the true founder of the dynamics. Besides, scientist and philosopher Galileo was also a musician, poet and man of letters. His mind, open to a multitude of interests and aspirations, was animated by a continuous dissatisfaction, which together with the dramatic events of his life, to family anxieties of all kinds, to the internal unrest between his religious conscience and inescapable scientific requirements, configured you a tormented personality.

The century of Galileo was the Counter-Reformation; its position against official culture and the predominant mindset of time is characteristic of dialectical contrast that, at the cultural level, can be established between structure and superstructure. That would be the scientific reasoning based on experience; This, the dominant cultural tradition in universities and academies, which defeated at the speculative level resists yet in men and in the institutions, and even boosts the counterattack against Galileo, man of the new science that at certain point is left alone and helpless against the authority of tradition.

Text of condemnation of Galileo

Because of its importance in the history of science and of thought we transcribe the text of condemnation of Galileo by the Roman Holy Office and the text of abjuration of Galileo before the Court.

1st. The condemnation of Galileo by the Court of the Holy Office. "... By how much you, Galileo, son of the late Vincenzo Galilei, Florence, seventy years of age, were denounced, in 1615, to this Holy Office for holding as true false doctrine taught by many, namely; that the Sun is stationary in the center of the world and that the Earth moves and possesses also a diurnal motion; as well as for having disciples who you teach in the same ideas; as well as to maintain correspondence on the same subject with some German mathematicians; as well as publish certain letters on the spots of the Sun, in which you develop the same doctrine as well as true; as well as to respond to the objections that they arise continuously by the Holy Scriptures, glossing the Scriptures according to your own interpretation; and as was presented a copy of a letter in the form of letter, written expressly for you for a person who was once your disciple, and in which, following the hypothesis of Copernicus, include several proposals contrary to the true meaning and authority of Holy Scripture; Therefore this sacred Court, eager to prevent disorder and prejudice that since then come and increase in impairment of the Holy faith, and according to the desire of his Holiness and the eminentisimos Cardinals of this Supreme universal Inquisition, qualifies the two propositions of the stability of the Sun and of the movement of the Earth, according to the theological qualifiers, as follows: 1. the proposal of the Sun being the center of the world and still on your website it is absurd, false philosophically and formally heretical, because it is precisely contrary to the Holy Scriptures. 2. the proposition if not the Earth the center of the world, or stationary, but it moves, and also with a diurnal motion, is also absurd, false philosophically and theologically considered, at least erroneous in faith.

But being determined this time to treat you with softness, the Sacred Congregation, gathered to his Holiness on 25 February 1616, decreed that his Eminence Cardinal Belarmino may prescribe you recant all of the mentioned false doctrine; and that if you rehusares to do so, you are required by the Holy Office Commissioner to renounce it, not to teach it to others or to defend it; and lack of acquiescence, that you're a prisoner; and therefore to complete this Decree the following day, at the Palace, in the presence of his Eminence Cardinal Bellarmine mentioned, after being lightly admonished by the Cardinal, you were ordered by the Commissioner of the Holy Office, before notary and witnesses, to renounce all the mentioned false opinion, and in the future, not defend it or teach it in any way, or verbally or in writing; and after promising obedience to it, you were dispatched.

And that a so pernicious doctrine can be removed entirely and not intimate longer with serious detriment of the Catholic faith, has been published a decree from the Sacred Congregation of the index, by banning the books dealing with this doctrine, by declaring it false and entirely contrary to the Holy and divine Scripture.

And since then has released a book published in Florence last year, whose title proved to be yours, namely: the dialogue of Galileo Galilei over the two main systems of the world: the Ptolemaic and the Copernican; and inasmuch as the Sacred Congregation has heard that as a result of the printing of this book is gaining ground daily opinion false motion of the Earth and of the stability of the Sun, has been carefully examined the aforementioned book and found in it one flagrant violation of the order previously given to you, any time that you defended in this book that opinion which had been condemned in your presence; Although in the same book you do many circunlocuciones to induce the belief that this is undecided and just as likely, which is also a very serious mistake, every time that it is not in any way likely an opinion that has already been declared and determined as contrary to divine Scripture. Therefore, by our order, have been cited to this Holy Office, where, after lent oath, have recognized the aforementioned book as written and posted by you. Also confess that you began to write this book is ten or twelve years, after having been given the order before mentioned. You also recognize that you've asked for license to publish it, without clarifying to which granted you this permission, that had received the order not to maintain, defend or teach this doctrine in any way. Also confess that the reader could judge the arguments adduced for the false doctrine, expressed in such a way that drove more effectively with the conviction that to a refutation of easy, claiming as an excuse that you've fallen into an error against your intention to write in dialogue form and, consequently, with natural complacency that each one by its own subtleties and show more skilled than the generality of mankind by inventing, still in favor of false propositions, ingenious and plausible arguments.

And after having given reasonable time to make your defense, showed a certificate with the character of letter of his Eminence Cardinal Bellarmine, got, as you said, by yourself, so you could defend yourself against the calumnies of enemies, who propalaban that you've abandoned your user and had been punished by the Holy Office; whose certificate declares that you had not renounced or you've been punished, but only that the statement made by his Holiness, and enacted by the Sacred Congregation of the index, you had been communicated, which declares that the view of the movement of the Earth and the stability of the Sun is contrary to Scripture, and that is why not it can be sustained or defended. So to not have been made there mention of two items on the agenda, namely: the order "not to teach" and "in no way", argüiste that we believe that in the span of fourteen or fifteen years had been erased from your memory, and this was also the reason why you saved silence regarding the orderWhen you asked for the permission to publish your book, and that this is said by you, not to excuse your mistake, but for which it can be attributed to ambition of pride rather than malice. But this same certificate, written in your favor, has considerably aggravated your offense, every time that he/she declares that the mentioned opinion is opposed to Holy Scripture, and, however, you've dared to take care of it and argue that it is likely. Nor is there any attenuation license torn, insidious and cleverly, every time that you not put revealed the mandate that had been imposed. But considering our opinion of not revealing the truth about your intention, we judge necessary to proceed to a rigorous examination in which you answered as a good Catholic.

Therefore having seen and considered seriously the circumstances of your case with your confessions and apologies, and all else that had to be seen and considered, we have arrived at the judgment against you, which is written below.:

Invoking the holy name of our Lord Jesus Christ and his glorious Virgin Mother María, pronounced this our final judgement, which, gathered in Council and Court with the Reverends masters of Sacred Theology and doctors of both rights, our advisors, we extend in this writing on issues and disputes between the magnificent Carlo Sincereo, doctor of both rights, fiscal Procurator of the Holy Office, on the one hand, and Galileo Galilei, accused, tried and convicted, on the other hand, we pronounced, judge and declare that you, Galileo, due to the facts that have been detailed in the course of this writing, and that you've previously confessed, you've made same vehemently suspect of heresy to this Holy Office you have believed and maintained the doctrine (which is false and contrary to the sacred and divine Scriptures) of the Sun is the center of the world, and that does not move from East to West, and that the Earth moves and is not the center of the world; also from that an opinion cannot be sustained and defended as probable after having been declared and enacted as contrary to Holy Scripture, and that therefore have incurred all the censorship and penalties contained and promulgated in the sacred canons and other General and special constitutions against offenders of this kind. Seen thus, it is our desire that you are acquitted, whenever with a sincere heart and true faith, in our presence you abjures, curse, and I hate about mentioned errors and heresies, and any other error and heresy contrary to the Catholic and Apostolic Church of Rome, in the way that now they will tell you.

But so your pitiful and pernicious error and transgression does not go entirely unpunished, and to be more prudent in the future and serve example so that others refrain from delinquencies of this genre, we decree that book dialogues of Galileo Galilei is banned by an edict of the public, and you condemn formal prison of this Holy Office for a determinable period to our will", and, by way of healthy penance, I ordered that the next three years recite, once a week, the seven penitential Psalms, reserve us the power of moderate, switched or deleted, all or part of the mentioned punishment or penance".

2nd. Formula of abjuration pronounced by Galileo Galilei. "I, son of the late Vincenzo Galilei, Galileo Galilei, Florence, seventy years of age, being personally cited to trial and kneeling before you, eminent and Reverend Cardinals, inquisitors General of the Republic universal Christian against the depravity of heretical, bearing the sacred Gospels which I touch with my own hands to me, I swear that I have always believed and, with the help of God"I will believe in the future, all items that the Holy Catholic and Apostolic Roman Church holds, teaches and preaches. Have received order of the Holy Office to abandon forever the false opinion that holds that the Sun is the Centre and still, being forbidden to maintain, defend or teach in any way such false doctrine; and since after having me stated that this doctrine is repugnant to Holy Scripture, I have written and published a book in which I try the same and condemned doctrine and rules reasons with great force in support of the same, without giving any solution; that have been tried as suspected of heresy, i.e. that I I maintain and I think that the Sun is the center of the world and still, and that the Earth is not the Center and is mobile, I want to remove from the minds of your Eminences and all Catholic Christian this vehement suspicion, just warm against me; that is why, with a sincere heart and true faith, I abjuro, curse and detest mentioned errors and heresies, and in general, any error and contrary to the Holy Church sectarianism; and I swear never again in the future I will say or will argue anything, verbally or in writing, giving rise to a similar suspicion against me; also, if you knew of some heretic or anyone suspected of heresy, denunciaré it to this Holy Office or the Inquisitor and ordinary of the place that I can find. I swear, in addition, and I promise that I will fulfill and faithfully will see all the penances that have been me or me are imposed by the Holy Office. But if it happens that I violate some of my such promises, oaths and protests (God forbid!), I put all the penalties and punishments that have been enacted and promulgated by the sacred canons and other General and special constitutions against offenders of this kind. Thus, with the help of God and of their Holy Gospels which I touch with my hands, I, formerly named Galileo Galilei, I renounce, promised and I've linked to this before; and testimony of this, with my own hand I have subscribed this present writing of my abjuration, which I have recited Word for Word.

In Rome, in the convent of the mining company, June 22, 1633; I, Galileo Galilei, he/she prosecuted as mentioned before with my own hand".