By Alex H. Elias A. Nina M. Avery S. Jupiter is the fifth planet in the solar system. Jupiter is also the closes Jovian planet to the sun. Jupiter is a gas planet so thus life would not exist on the planet. Thankfully, it has moons! Hooray! With 63 total moons, Jupiter has many natural satellites. These moons are of many different sizes, but most are under 3 km. wide. There are four large and very prominent moons. These moons are Io, Europa, Ganymede and Callisto. They were all discovered by Galileo in 1610. Io is a very hot place at 1800 Kelvin. It has a lot of volcanic activity, the most in the solar system. With volcanic eruptions daily (400 active volcanoes), along with massive lava flows. Io orbits very close to the outer atmosphere of Jupiter. Io also has a high concentration of sulfur in its atmosphere. Europa is covered with ice but, underneath is a sea! Europa orbits in an oval around Jupiter, this means that there are tides beneath the ice caused by Europas unique elliptical orbit. It is slightly smaller than Earths moon and it always has the same side facing Jupiter. Its atmosphere is filled with oxygen! It has a surface temperature of -260 degrees Faherenheit Ganymede is the largest satellite in the entire solar system!!! The moon is approximately half silicate rock, and water ice. A salt water ocean is believed to exist 200 km. below the surface. Ganymede is the only satellite in the solar system believed to have a magnetic field because of its supposed hot iron core (oh wow)! Callisto is the third largest moon in the solar system! Can you believe it?!? I sure can. Similar to Ganymede, Callisto is supposed to be composed of half ice, and half rock. The surface is heavily cratered and very old. This moon, unlike others is not rumored to have any undersurface activity. This moon is a big cold rock. Period. A planet must possess relatively clean liquid water, there has to be organic molecules that can transform into life, and energy sources to maintain metabolism. The planet must be at the ideal distance from its sun, in order to sustain a temperature that is suitable for life. The sun must be consistently giving off heat and light so that life can form under similar circumstances and evolve over time We know that there is a lot of volcanic activity on Io which is how the Earth was in the beginning. Based on that, there could be certain elements that will be in the lava that will come into the atmosphere and could make life sustainable. Since Io looks like a primitive Earth the possibilities for life are just now forming. Yes! Europa could potentially sustain life. Not only is it covered in ice (water), but there is a hidden sea underneath all those layers. The planet is cold, but its heat source is Jupter; pulling the tides of its sea. Oxygen is a necessity, and Europas got it! There has been discovery of bacteria in Earths harshest conditions, that are much like Europas. Possibly but not likely. Ganymedes source of water is extremely salty. No life form we know of can survive solely upon this. But you never know. Although the temperatures are very low, and atmosphere is little to none; Ganymede has a strong magnetic field. This could protect life from damaging radiation. Not likely.. This moon is one hundred percent desolate. Unlike Europa and Ganymede who prove that there is more than meets the eye, Callisto proves otherwise.. It is a big cold rock. But not all hope is lost! Ice covers much of the moon. Ice = water. The atmosphere is also decently sustainable. With these moons the orbit Jupiter, it really opens the possibility for other life in our solar system. The circumstances these moons are under currently hold the most likely conditions for life. If the conditions evolve or just shift slightly, the probability for life would be almost 100%!!!!