Galileo is known as science s most dramatic character. He is known as a rebel philosopher who advocated free though in a country where individual opinion was detested. He confronted authority and tradition by putting his beliefs in his scientific work before those of religion. His concept of questioning and searching for the truth led to many discoveries such as the isochronism of the pendulum, disapproving the accepted Aristotelian concept of the fall of weights, construction of the telescope which was a far more powerful instrument that anyone had ever seen and through it he discovered satellites of Jupiter as well as many others.
Born of an in Pisa, Tuscan on February 15, 1564, Galileo was the oldest son of Vincenzio Galilei. (Book Galileo, page 59) When he was a young boy his family moved to Florence where he received his early education in a nearby monastery. Then in 1581 he was sent to the University of Pisa to study medicine. Galileo had little interest in medicine and found his classes boring.
But his active and curious mind led him into the world of science. He was sitting in the cathedral at Pis while the lamps were being lighted. He noticed that the lamps were swinging and some had wider arcs then others. He expected that the lamps with the wider swings would require more time so he timed them by the beat of his pulse and found that all the swings took the same time. The lamp was acting like a pendulum and these observations showed that any pendulum must therefore be isochronous, performing all swings in equal times.
He also implied his findings about pendulums to invent a timing advice. What was most important is that Galileo had set the pattern of his life. A simple observation led him to questions and experiments which led to new knowledge and applications.
The first sign of him being a rebel was shown when he decided to leave medical school without a degree and return to Florence against his father s wishes. He decided to make the mathematical subjects and philosophy his profession. During this time he designed a new form of hydrostatic balance for weighing small quantities and wrote, La Bilancetta (The Little Balance ) that circulated as a manuscript among his friends describing his work. (http://www.britannica.com leb/article? eu=108035&tocid=8440) This brought him to the notice of scientific circles in Florence and began to establish his reputation as a mathematician.
In 1589, he obtained the chair of mathematics at the University of Piza. Here he performed an experiment questioning work previously accepted by Aristotle. He demonstrated, by dropping different wights from the top of the leaning tower of pis, that the speed of fall of a heavy object is not proportional to its weight, as Aristotle had claimed. He wrote the manuscript De Motu (On Motion) which shows that he abandoned his notions and these attacks on Aristotle made him unpopular with his colleagues, and in 1592 his contract was not renewed. What this clearly shows is Galileo s ability to branch out along a new line and in a new way study the natural world.
From 1592 to 1610 be taught at the University of Padua where his salary was considerable higher. His father had died in 1591 and he was pressed for money because of the cost and responsibility of being the head of the family. To compensate he sold a proportional compass, a sector, of his own devising, made by an artisan whom he employed in his house. By 1609 he had determined that the distance fallen by a body is proportional to the square of the elapsed time (the law of falling bodies) and that the trajectory of a projectile is a parabola. (Http://galileo. imss.firenze/it/b/egaglilg.html) Both conclusions that contradicted Aristotelian physics.
In the spring of 1609, Galileo s life took a dramatic turn. He heard that in the Netherlands and instrument had been invented that showed distant things as though they were near by. Through trial and error, he quickly figured out the secret of the invention and made his own three powered spyglass from lenses for sale in spectacle makers shops. It is a combination of two lenses, on plane concave and the other inside a tube. The lenses are placed with one close to the eye (ocular) and the other at the end of the tube (objective). (http://galileo.imss.firenze.it/museo/ alecannoc.html) He had improved the instrument by increasing its enlarging power and gave it an upright image which transformed it into a tool used for astronomical research. It was named the telescope. In August of that year he presented an eight powered instrument to the Venetian Senate and was rewarded with life tenure and his salary was doubled. With this new discovery many men would have been content to sit back and rest and take life easy. This was not Galileo s way. He continued to ask questions and to experiment. He was able to construct a microscope that magnified the image thirty times. It was with this instrument that he began to examine the heavens and make a series of discoveries that were to make him famous.
What Galileo saw when he used the telescope astronomically astounded him. At every turn, whichever way he looked, cracks appeared in the fabric of the Aristotelian cosmos. (Book) Every observation showed him something new, every observation showed visual evidence against the arguments that Earth was stationary. He began to publish his findings. In March 1610 The Starry Messenger, was published. In this he stated that the Moon s surface is not smooth, as had been thought by the Aristotelians, but is rough and uneven. The telescope also showed a large amount of stars not visible to the eye alone. He also saw the Milky Way and described it as, a hazyt irregular band of starlight that seemed to stretch unbroken right across the sky. In the closing section of the Starry Messenger, Galileo described his observations of Jupiter, perhaps the most important of his astronomical discoveries. He saw that is possessed a disk and was accompanied by four satellites. He noticed that four bright starts close to Jupiter were actually in orbit around it. He observed and studied the oval shape of Saturn, the phases of Venus and the spots on the sun. These discoveries were important because they demonstrated the power of accurate observation with a suitable instrument. It was the development of the use of special equipment for obtaining answers to specific questions and it established observation as a primary source of evidence.
His investigations confirmed his acceptance of the Copernican theory of the solar system that the sun is the centre of the universe and that Earth was a planet. He did not declare a doctrine so opposed to accepted beliefs until 1613 when he issued a work of sunspots. (Web page new). In 1611 he visited Rome to display the telescope to the papal court. In 1616 the system of Copernicus was denounces as dangerous to faith and Galileo was warned not to uphold it or teach it. But in 11632 he published a work written for the nonspecialist on the dialogue of the two chief systems of the world. That work, which supported the opposed Copernican system was a turning point in scientific and philosophical thought. He was summoned to Rome where a tribunal of seven Cardinals required Galileo to solemnly abjure his theory. Galileo did not do this and he would obstinately go his own way in spite of the dangers. He would not leave the authorities alone. He was determined for them to admit that a moving Earth was not heretical. The Vatican warned him that formal charges would be pressed unless he abandoned his ideas that Copernicus was correct and the Roman Catholic Church was wrong. In March 1616 all Copernican theories were banned, but Galileo ignored the warning and continued to spread the word of his beliefs. In October of 1632, Galileo was ordered to appear in front of an Inquisition, the court of the Roman Catholic church. In April of 1633, Galileo went before the court and was order to drop all Copernican theories or else he would be tortured and executed by burning at the stake for heresy. On My 10th he admitted to heresy in writing and on June 22nd he publicly confessed. He was then sentenced to house arrest in his home near Florence for an indefinite length of time. He was also forbidden to publish and teach. It seemed like Galileo would have given up on investing and discovering new ideas but he didn t. He continued to research and invented new instuments. He also wrote his great book on motion and mechanics summing up his life s work in the field.