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. Aristotle was so popular that Galileo soon lost his teaching job, and so sought work in Padua.  It was here that his astronomy career began.

In Padua, Galileo invented the compass and began studying physics.  He developed formula for the path projectiles took, and for falling bodies.  These two ideas were key to astronomy as it progressed.  However except for an allegiance to the work of Copernicus over Ptolemy and Aristotle, Galileo claimed to be disinterested in astronomy.  Copernicus' theory was of a heliocentric solar system in which the planets circle the sun.  Aristotle and Ptolemy held that the solar system was centered around the Earth, and even the sun rotated around our home.  As time went by Copernicus, and Galileo, were proven correct.

When the spyglass was invented in Holland, Galileo learned of it and made his own telescope which he turned to the sky.  He used it to see features on the moon such as mountains and craters.  He also learned that the milky way was made up of individual stars.  He also saw four large moons orbiting 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.  In only 9 months he determined that other planets had phases.  This further contradicted Ptolemy while proving that Copernicus was right.

Galileo's original dispute was with Aristotle's teachings.  Because so many agreed with Galileo his theories were widely published.  But because Aristotle's work elevated man to key position in all the universe, the church supported his work.  In 1614 a priest in Florence denounced Galileo Galilei Astronomy.  Galileo retorted that the bible has no bearing on science.  In 1616 Galileo was ordered to stop teaching that the Earth revolves around the sun.  Galileo complied, continuing his study of falling objects, comets, and methods to determine longitude at sea based on the phases of Jupiter's moons.  It was upon signing a document stating the Earth is stationary Galileo uttered a famous quote.  "I would say here something that was heard from an ecclesiastic of the most eminent degree; "And yet ... it moves."