Learning about Jupiter
Jupiter's four largest moons are called the Galilean satellites, after Italian astronomer Galileo Galilei, who observed them in 1610. The German astronomer Simon Marius claimed to have seen the moons around the same time, but he did not publish his observations and so Galileo is given the credit for their discovery. These large moons, named,Io Europa, Ganymede, and Callisto. Io is the most volcanic body in the solar system. Jupiter's immense gravity causes "tides" in the solid surface that rise 300 ft high on Io, generating enough heat for volcanic activity and to drive off any water. Europa's surface is mostly water ice, and there is evidence that it may be covering an ocean of water or slushy ice beneath. Europa is thought to have twice as much water as does Earth. Ganymede is the largest moon in the solar system (larger than the planet Mercury), and is the only moon known to have its own internally generated magnetic field. Callisto's surface is extremely heavily cratered and ancient.
The Great Red Spot
The Great Red Spot is a storm that is ancient. It is so large that 3 earths could fit in it. It is a very powerful storm that is worse than a hurricane. It was discovered in the 17th century by Galileo Galilee.