On 7th January 1610, Galileo Galilei observed Jupiter’s moons for the first time. The Galilean moons, as they have come to be known, are the largest moons of planet Jupiter – Ganymede, Callisto, Io and Europa.
Galileo Galilei had demonstrated his telescope on 25th August 1609 and was the first astronomer to observe the planet Neptune, though he wrongly classified it as a fixed star.
