Galileo Galilei, an astronomer, physicist, mathematician, and inventor, is one of the most famous scientists of all time. He was born in Pisa, Italy. At first, Galileo enrolled in the University of Pisa to earn a medical degree, but he switched his focus to mathematics. Here are some facts about Galileo.
Galileo was a proponent of the heliocentric theory of the universe, which was an unpopular theory at the time because it was disapproved of by the Roman Catholic Church and believed to be false by the majority of people. Galileo stood trial for heresy in 1633 after he published his book, Dialogue Concerning the Two Chief World System, which discussed the theory of heliocentrism. Because the heliocentric model was in direct contrast with the Church’s view, Galileo was forced to withdraw many of his theories and spent the last years of his life under house arrest. Galileo’s works were banned from being reprinted until 1718, which was over 60 years after his death. While he was under house arrest, Galileo went blind but he continued to invent and theorize.
Galileo disagreed with Kepler’s theory that the Moon caused tides on Earth. Instead, he thought that the tides were caused by the Earth’s rotation and orbit around the Sun. As the planet moved, the oceans sloshed around resulting in tides. This supported his theory of heliocentrism. As we now know though, Galileo was wrong. It is indeed the Moon that causes tides on Earth.
Using a telescope he had built, Galileo discovered four of Jupiter’s moons: Io, Ganymede, Callisto, and Europa. Although at first Galileo called them the Medicean stars to honor the person who would become his patron and his future patron’s three brother, the moons were renamed as the Galilean moons. Many people did not believe that these moons existed because it did not go along with popular thought at the time.
Although Galileo was not the first person to create the telescope, he improved on earlier models to create one with 3x magnification. Later, he built a telescope with 30x magnification. Galileo was an excellent inventor who made some other important contributions to science. He also worked on a pendulum clock, although the first working one was built by Christiaan Huygens. Galileo was the first person to report finding craters on the Moon, using one of his telescopes. He was even able to roughly estimate the height of the mountains he thought he saw.
Astronomy Cast has an episode on choosing and using a telescope.