Galileo's Observations

Galileo's observations revolutionized our understanding of the cosmos. Using his telescope, he discovered that the Moon has mountains and craters, challenging the idea that celestial bodies are perfect. He observed Jupiter's four largest moons—Io, Europa, Ganymede, and Callisto—showing that not everything orbits Earth, supporting the heliocentric model. He also noted that Venus exhibits phases like the Moon, further proving it orbits the Sun. These findings provided strong evidence against the longstanding geocentric view and helped establish a new, more accurate understanding of the solar system's structure.