Galileo Galilei


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  • Galileo Galilei was born in Pisa, Italy, on the 15th of February 1564, he died on the 8th of January 1642.

  • Galileo was a ground breaking astronomer, physicist, mathematician, philosopher and inventor. Among his inventions were telescopes, a compass and a thermometer.

  • Galileo enrolled to do a medical degree at the University of Pisa but never finished, instead choosing to study mathematics.

  • Galileo built on the work of others to create a telescope with around 3x magnification, he later improved on this to make telescopes with around 30x magnification.

  • With these telescopes, Galileo was able to observe the skies in ways previously not achieved. In 1610 he made observations of 4 objects surrounding Jupiter that behaved unlike stars, these turned out to be Jupiter’s for largest satellite moons: Io, Callisto, Europa and Ganymede. They were later renamed the Galilean satellites in honor of Galileo himself.

  • The discovery of these moons was not supported by the scientific principles of the time and Galileo had trouble convincing some people that he had indeed discovered such objects. This was similar to other ideas put forward by Galileo that were very controversial at the time.

  • The Geocentric model of the universe which was embraced by earlier astronomers had the Earth at the center of the universe with other objects moving around it. Work by Galileo, Nicolaus Copernicus and Johannes Kepler helped to supercede this theory with the more accurate heliocentric model. Such a view of the universe differed strongly with the beliefs of the Catholic Church at the time and Galileo was forced to withdraw many of his ideas and even spent the final years of his life under house arrest.

  • Galileo refused to believe Kepler’s theory that the moon caused the tides, instead believing it was due to the nature of the Earth’s rotation (helping prove that even the smartest people can make mistakes).

  • Famous Galileo quotes include: “In questions of science the authority of a thousand is not worth the humble reasoning of a single individual.”

  • “See now the power of truth; the same experiment which at first glance seemed to show one thing, when more carefully examined, assures us of the contrary.”

  • “Alas! Your dear friend and servant Galileo has been for the last month hopelessly blind; so that this heaven, this earth, this universe, which I by my marvelous discoveries and clear demonstrations had enlarged a hundred thousand times beyond the belief of the wise men of bygone ages, henceforward for me is shrunk into such a small space as is filled by my own bodily sensations.”




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