Galilean Moons Of Jupiter. One dark, clear January night in 1610, Galileo Galilei climbed to the roof of his house in Padua. He looked up at the sky that was speckled with the flickering fires of a multitude of starry objects, and then aimed his small, primitive "spyglass"--which was really one of the first telescopes--up at that star-blasted sky above his home. Over the course of several such starlit, clear winter nights, Galileo discovered the four large Galilean moons that circle around the largest planet in our Sun's family, the enormous, gaseous world, Jupiter. This intriguing quartet of moons--Io, Europa, Ganymede, and Callisto--were named for four of the numerous mythic lovers of the King of the Roman gods.
Full moons on different days. Where you live on earth rarely makes a difference as to whether the moon is full, quarter or new. This is because it takes the moon almost a month to travel around the earth and it only takes a day for the earth to turn around once. So in comparison, the moon sort of sits in the sky and waits for us to see what phase it is in. Still, there are times when the moon will be full on different calendar days in different areas of the earth.
Saturn, the smaller of the two gas-giant planets inhabiting our Solar System, is an enchanting world. It is dwarfed only by Jupiter, the larger gas-giant planet, and it is probably the most beautiful planet in our Solar System. Magical and mysterious, Saturn's lovely rings and tumbling moonlets of ice, evoke wonder in the eye of the beholder.