Ganymede (moon) (JUICE), due to launch in 2022. After flybys of all three icy Galilean moons, the probe is planned to enter orbit around Ganymede. Chinese astronomical records report that in 365 BC, Gan De detected what might have been a moon of Jupiter, probably Ganymede, with the naked eye. However, Gan De reported the color of the companion as reddish, which is puzzling since the moons are too faint for their color to be perceived with the naked eye. Shi Shen and Gan De together made fairly accurate observations of the five major planets. On January 7, 1610, Galileo Galilei observed
Discovery and exploration of the Solar System Domenico Cassini later discovered four more moons of Saturn and the Cassini division in Saturn's rings. Edmond Halley realised in 1705 that repeated sightings of a comet were recording the same object, returning regularly once every 75–76 years. This was the first evidence that anything other than the planets orbited the Sun. Around this time (1704), the term "Solar System" first appeared in English. In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet. Its orbit revealed that it was a new planet, Uranus, the first