Galileo Galilei
Galileo Galilei was in Italian astronomer, mathematician, and physicist. He has been called the founder of modern experimental science. He found an effective way to use the refracting telescope and designed many scientific instruments during his life, as well as developing and improving the telescope.
Galileo was born in Pisa, Tuscany on February 15, 1564. He was the oldest son of the family. Galileo's father was a musician and mathematician. During the early 1570's, his family moved to Florence where Galileo began his education at a nearby monastery. His father wanted him to become a doctor, so he later attended the University of Pisa in the field of medicine. However, because of financial reasons, he left the university without a degree. He applied for the chair of mathematics at the University of Bologna but was turned down. As his reputation continued to increase, however, he was offered the same position at the University of Pisa.
He experimented with motion and found that the speed of the fall of a heavy object is not proportional to its weight, contrary to Aristotle's theories. It is said that Galileo dropped objects of different weight off the Leaning Tower. Aristotle's theories were widely accepted and Galileo soon became unpopular. His contract was not renewed at the university. He later joined the University of Padua and taught geometry, mechanics, and astronomy. He made many significant discoveries during this time, such as the law of falling bodies and the pendulum.
There were many things that made Galileo famous. It is commonly mistaken that Galileo invented the telescope. Despite this fact, however, he did develop and improve it. He made an improved model that could magnify up to 32 times. Although this wasn't much compared to our modern telescopes, Galileo was one of the best telescope makers at the time. Using the telescope, he found the four largest moons of Jupiter: Io, Europa, Cllisto, and Ganymede. This helped to support Copernicus's theory that the earth revolves around the sun. However, Copernicus died before he could prove his theory. Galileo's findings also disapproved the geocentric theory, in which everything circled around the earth. The moons, called Galilean moons, are now named after him. Later, Galileo observed the earth's moon. He found that it received light from the sun, instead of making its own light. He also found craters and mountains, which contradicted Aristotle's thinking of a smooth, perfect landscape. The previous theories of Aristotle and many other philosophers, such as Ptolemy, had been widely accepted, therefore, Galileo's ideas were usually disapproved. Aristotle's thinking was based on logic and common sense. Galileo used experiments in order to prove his theories instead.
Galileo continued to observe the rest of the universe. He found that the Milky Way, which was believed to be a cloud of dust, was actually made up of many stars. He also observed Venus and found that it had phases, similar to the moon. Galileo also found observed Neptune, although he didn't realize it was a planet and mistook it for a dim star. He found that Saturn had rings of dust as well. Galileo was also one of the first Europeans to observe sunspots. His findings contradicted the geocentric system again, which said that everything was a perfect “heaven.”
