Galileo Galilei (1564-1642) was an Italian physicist, astronomer, and philosopher who played a major role in the Scientific Revolution. Some of his key achievements include improvements to the telescope that enabled new astronomical observations. He was born in Pisa, Italy and studied medicine at his father's insistence before switching to mathematics. Galileo made contributions to the fields of physics, astronomy and philosophy through his inventions like the thermometer and telescope, as well as his astronomical observations of mountains on the moon and Jupiter's moons. However, he faced opposition from the Catholic Church for his support of Copernicus' heliocentric model of the solar system and was eventually placed under house arrest for the rest of his life