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Near the end of the 16th century, a man named Galileo was born in Italy.  In his early career he taught math at a university, the beginnings of his fame.  Galileo the math teacher made his first step into Galileo Galilei astronomy when he demonstrated to his students that Aristotle was wrong about object of different weights falling at different speeds. He lost his position for this perceived insult of a respected great, so he moved on to the University of Padua. Galileo contributions to astronomy would come to fruition there.

In Padua, Galileo invented the compass and began studying physics. He discovered the law of falling bodies and the parabolic path of projectiles. These became very important in later Galileo Galilei astronomy. 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. Aristotle and Ptolemy held that the solar system was centered around the Earth, and even the sun rotated around our home. The model Copernicus proposed for the order of planets around the sun has been proven. And today we know Copernicus was completely correct.

Galileo was the first to look at the night sky through a spyglass, thus using the first telescope.  With a magnification of 20, this telescope helped Galileo discover mountains and craters on the moon.  Galileo also determined that individual stars made up what was called the Milky Way.  He also saw four large moons orbiting Jupiter.  After publishing this information, he was named the royal mathematician in the court at Florence.  Now he could devote full time to his studies.  Nine months later he showed that Saturn had phases.  This further contradicted Ptolemy while proving that Copernicus was right.

Galileo’s original dispute was with Aristotle’s teachings. Many scientists agreed with Galileo, and so published his findings. But Aristotle was popular with the church because an Earth centered solar system put man’s home, and thus man, at the center of things. In 1614 a priest in Florence denounced Galileo Galilei Astronomy. Galileo responded by writing a letter proclaiming the bible irrelevant to science. In 1616 the church censored Galileo’s books, and a cardinal instructed him to stop teaching that the Earth moves. 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 is said that Galileo had one comment after signing an agreement that the Earth does not move. “I would say here something that was heard from an ecclesiastic of the most eminent degree; “And yet … it moves.”

Near the end of the 16th century, a man named Galileo was born in Italy.  He eventually became a mathematics teacher despite having no degree, and it was here that his famous future was first hinted.  Galileo the math teacher made his first step into Galileo Galilei astronomy when he demonstrated to his students that Aristotle was wrong about object of different weights falling at different speeds. He lost his position for this perceived insult of a respected great, so he moved on to the University of Padua. Galileo contributions to astronomy would come to fruition there.

In Padua, Galileo invented the compass and began studying physics.  He discovered the law of falling bodies and 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’ theory was of a heliocentric solar system in which the planets circle the sun.  But in the work of Ptolemy and Aristotle the solar system circled the Earth.  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. With a magnification of 20, this telescope helped Galileo discover mountains and craters on the moon. He also learned that the milky way was made up of individual stars. He went on to discover Jupiter’s four largest moons. He published his findings and became the court mathematician in Florence. With time freed from teaching duties, he could really get to work. It took him only 9 months to discover Saturn’s phases. This further contradicted Ptolemy while proving that Copernicus was right.

Galileo had a long standing feud with Aristotle’s beliefs and teachings.  Because so many agreed with Galileo his theories were widely published.  But the powerful church was inclined to believe Aristotle’s theories which placed man at the center of creation. 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.  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.”