DISCOVERED BY: GALILEO GALILEI AND SIMON MARIUS
WHEN: JANUARY 7TH 1610
HOW: GALILEO LOOKED THROUGH ONE OF HIS PRIMITIVE TELESCOPES, AT JUPITER AND SAW FOUR STARS THAT ORBITED ARIUND JUPITER, IO, EUROPA, GANYMEDE, AND CALLISTO
Sources
http://science.nasa.gov/headlines/y2003/02jul_harrypotter.htm
http://www.enchantedlearning.com/subjects/astronomy/planets/jupiter/moons.shtml
http://www.knowledgerush.com/kr/encyclopedia/Callisto_the_moon/
