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Galileo Galilei: 400 Years of Stellar Observations
Physicist, mathematician, astronomer, philosopher – Galileo Galilei was all of this and more. His improvements to the telescope led to the discovery of the four largest moons of Jupiter, which are named in his honor.
The Galilean moons – Io, Europa, Ganymede and Callisto – were discovered 400 years ago on Jan. 7, 1610, a year after Galileo made his first telescope in 1609. Modeled after telescopes produced in other parts of Europe that provided 3 times magnification, Galileo’s telescope could magnify objects twenty times. This enabled him to provide humanity with the first detailed observations of Earth’s moon. He subsequently observed a supernova, verified the phases of Venus, and discovered sunspots. His discoveries proved without a doubt that Copernicus was right – the Earth and other planets do indeed revolve around the sun. The world was no longer geocentric after all.