The Galilean Satellites



This composite of the Galilean Satellites shows images of the moons taken by the Galileo spacecraft. Details of their surfaces are given in the lower two rows of the composite, including features produced through volcanism, ice, and cratering.
Click on image for full size version (60K JPG)
Image from: NASA
The Galilean satellites are the 4 major moons of Jupiter, Io, Europa, Ganymede, and Callisto. In this picture, Io, and Io’s surface, are shown on the left-most end, then Europa, and its surface, then Ganymede, then Callisto. Of Jupiter’s 60 moons, these four are the biggest.

These moons were discovered by Galileo Galilei in 1610. Their discovery by Galileo provided the key piece of evidence for Galileo's proof that the Earth was not the center of the Universe. Although Galileo initially thought they were stars, through continued observations over a couple of weeks, he realized that the objects he had observed remained in the vicinity of Jupiter. He was finally able to show that these objects were orbiting Jupiter, thus proving that not all objects in the heavens orbited the Earth.

Interestingly, Galileo named these natural satellites of Jupiter the "Medicean satellites" , after the famous Medici family of Renaissance Italy. The colorful names we now use for these satellites can be attributed to Simon Marius (who claimed to have observed the satellites before Galileo in 1609, but did not publish his findings). Marius attributed the suggestion of these names to a suggestion from Johannes Kepler in 1613.



Galilean Satellites



This composite of the Galilean Satellites shows images of the moons taken by the Galileo spacecraft, as well as details from the surfaces of the moons.
Click on image for full size version (60K JPG)
Image from: NASA
The Galilean satellites are the 4 major moons of Jupiter, Io, Europa, Ganymede, and Callisto. In this picture, Io, and Io’s surface, are shown on the left-most end, then Europa, and its surface, then Ganymede, then Callisto. Of Jupiter’s 60 moons, these four are the biggest.

These moons were discovered by Galileo Galilei in 1610. Their discovery by Galileo was a key piece of evidence that the Earth was not the center of the Universe. Although Galileo initially thought they were stars, his continued observations over a couple of weeks showed that the objects remained near Jupiter. He was finally able to show that they were in orbit around Jupiter, thus proving that not all objects in the heavens orbited Earth.



Galilean Satellites



This picture shows images of the Galilean Satellites taken by the Galileo spacecraft, as well as details from the surfaces of these moons.
Click on image for full size version (60K JPG)
Image from: NASA
The Galilean satellites are the 4 big moons of Jupiter, Io, Europa, Ganymede, and Callisto. These moons are called Galilean because they were discovered by Galileo Galilei in 1610.

In this picture, Io, and Io’s surface, are shown on the left-most end, then Europa, and its surface, then Ganymede, then Callisto. Of Jupiter’s 60 moons, these four are the biggest.



Last modified September 19, 2003 by Roberta Johnson.
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