Jupiter is the largest planet in our solar system. It is the 6th planet from the sun and is a gas giant (Mostly hydrogen and helium). However, most scientist believe that Jupiter contains a solid core Jupiter is about 1,300 times larger than Earth. Jupiter has a mass that is about two and a half more than Earth. This means that a a person weighing 100 pounds on Earth would weigh about 250 pounds on Jupiter. Jupiter was named after the Roman king of Gods.
When the telescope was invented by Galileo in 1610, he witnessed four of Jupiter's moons orbiting around it. This changed the way mankind saw the Universe. Up until then, it was thought that everything in the universe orbited around the Earth. Galileo use this information (along with other observations) to support the theory that the Earth and other planets orbited around the sun. This belief almost cost him his life as it was against the thinking of many powerful people of the day.
An interesting feature on Jupiter is the Red Spot. This is actually a hurricane that is three times wider than Earth at its widest point. It has been spinning for about 300 years with winds of 225 miles per hour. Temperatures on Jupiter average a frigid -234 degrees below zero.
Jupiter revolves (spins) faster than the other planets. A day on Jupiter is only 10 hours. Jupiter's magnetic field is 20,000 times more than Earth. This energy is 1000 times more than what is needed to be fatal to a human. Jupiter's strong gravitational field has a big impact on our solar system (And thus Earth). It holds the asteroids in check from entering the inner solar system where we live. Occasionally and asteroid may escape Jupiter's gravity and pose a threat to Earth. It is believed that an asteroid may have struck Earth about 60 million years ago wiping out the dinosaurs and much of life on Earth.
Jupiter has 63 moons. The largest, Ganymede, is the largest moon in our solar system. It is the only moon with a magnetic field. It is believe to have a liquid ocean contained under layers of ice.