A simplified illustration of the parallax of an object against a distant background due to a perspective shift. When viewed from Viewpoint A, the object appears to be in front of the blue square. When the viewpoint is changed to Viewpoint B, the object appears to have moved in front of the red square.
From top to bottom: Io, Europa, Ganymede, Callisto. The Galilean moons are the four largest moons of JupiterâIo, Europa, Ganymede, and Callisto. They were discovered by Galileo Galilei around January 1610 and were the first group of objects found to orbit another planet. Their names derive from the lovers of Zeus.
No one knows when Jupiter was discovered. The planet was known to the ancients and named after the chief god of the Romans. However, it's believed that the Chinese astronomer Gan De discovered one of Jupiter's many moons in 362 B.C. Jupiter's rings were discovered in 1979 by Voyager I. Continue Reading.