Galileo Galilei Astronomy

Galileo was born in Pisa, Italy in the late 1500's. In his early  career he taught math at a university, the beginnings of his fame. It was as a math teacher that he first showed students that Aristotle was incorrect in his claim that a heavier object would fall faster than a lighter one. He lost his position for this perceived insult of a respected great, so he moved on to the University of Padua. His entry into astronomy would come to fruition there.

While teaching in Padua he developed the compass and began to delve into the subject of physics. He expanded his work on falling bodies, writing formula to describe them as well as the parabolic path of projectiles. These two ideas were key to astronomy as it progressed. But at the time Galileo claimed to have no interest in the subject other than that he believed the work of Copernicus rather than that of Aristotle and Ptolemy. Copernicus had proposed that the solar system is heliocentric, that is that the planets rotate around the sun. However most people held that Aristotle and Ptolemy were correct in their theory that all the planets, even the sun, orbited the Earth. As time went by Copernicus, and Galileo, were proven correct.

Shortly after the spyglass was invented in Holland Galileo decided to make his own for peering at the night sky. This telescope magnified objects 20 times, which was enough to make out craters and mountains on the moon. Galileo also determined that individual stars made up what was called the Milky Way. Next he found the four largest moons of Jupiter. After publishing this information, he was named the royal mathematician in the court at Florence. No longer having to earn a living teaching, he could spend more time exploring. It took him only 9 months to discover Saturn's phases. It was yet more proof that his trust in Copernicus was well founded.

Galileo had a long standing feud with Aristotle's beliefs and teachings. Galileo found a great deal of support with other modern scientists who wrote of his work. But because Aristotle's work elevated man to key position in all the universe, the church supported his work. A Florence priest denounced Galileo Galilei astronomy in 1614. Galileo responded by writing a letter proclaiming the bible irrelevant to science. A cardinal demanded Galileo stop talking about a moving Earth. Galileo complied, continuing his study of falling objects, comets, and methods to determine longitude at sea based on the phases of Jupiter's moons. Galileo signed a document proclaiming his agreement with the Earth centered solar system, one in which the Earth doesn't move. But he had one more thing to say on the subject. "I would say here something that was heard from an ecclesiastic of the most eminent degree; "And yet ... it moves."