Jupiter’s moon, Io, is a very interesting place.  Io was discovered on the 8th of January 1610 by Galileo.  The moon itself looks like a giant cheese pizza, with cheese, Olives, and Tomato.  On its surface, the most violent eruptions in our galaxy are taking place constantly due to the hundreds of volcanoes on its surface erupting regularly.  Surprisingly, Io is only a small amount larger than our moon, and still one of the largests moons on Jupiter.  Since Jupiter is so much larger than Earth, it has much more gravity.  This large amount of gravity causes Io to have tides where matter is pulled toward Jupiter from Io, but unlike Earth’s tides in which the oceans are pulled outwards Io’s solid surface bulges up to 100m (330 ft) from its normal size!  Over all Io is definitely one of Jupiter's coolest moons.  Io is not just a made up name for a moon, Io comes from Greek mythology.  The story is that Jupiter, king of the gods, liked a daughter of Inachus named Io. But in order to hide her from his wife, Juno, he turned Io into a cow.  That is why the people that named Jupiter’s moons named one of them Io.