Galileo Galilei observes Jupiter’s four largest moons, disproving church dogma that all movement in the universe is centered on Earth. (apr 1, 1609 – jun 1, 1609)
Description:
Galileo made an astounding discovery when he focused his telescope on Jupiter, the biggest planet in our solar system. There were four "stars" around the planet. Within a few days, Galileo discovered that these so-called stars were actually Jupiter's moons in orbit.source: https://education.nationalgeographic.org/resource/galileo-discovers-jupiters-moons/
Added to timeline:
Date:
apr 1, 1609
jun 1, 1609
~ 2 months