WELCOME TO JUPITER

Jupiter is the biggest planet in the Solar System and is the first of the four Gas Giants. Earth could fit into Jupiter over 1300 times! The planet has a very strong pull of gravity and a very thin ring spinning around it, just like Saturn's rings only much, much thinner. Jupiter is made up almost entirely of gas. This means that the whole planet is just like sky without any land below it. In this sky are electrical storms (lightning) and winds and hurricanes. Jupiter may have a very small liquid or solid centre which would be only the same size as Earth. This is because the pressure would be so intense at the centre that the atmosphere would feel so 'heavy' at the centre of the planet so that hydrogen molecules (tiny bits of hydrogen) would break down to form a ball of metallic liquid or solid. This metallic core is very dense and is extremely magnetic, causing Jupiter's strong magnetic field. It is this magnetic field that causes Jupiter to create twice as much heat than it receives and, with the gravitational pull of Europa, Jupiter's second large moon, cause Io, Jupiter's closest large moon, to have the most volcanic surface in the Solar System.

Jupiter's main feature is its Great Red Spot, which is a storm that has been going on for centuries and was first observed by an astronomer called Robert Hooke in 1664! The planet also has an extremely strong magnetic field, extending all the way to the most distant moons of Jupiter. the next planet in the Solar System. The Sun contains 98% of the matter (the objects) in the Solar System. About 70% of this matter is Jupiter! Jupiter is sometimes seen as the Solar System's vacuum cleaner, as its huge size, strong gravitational pull and magnetic field suck up comets, asteroids and meteors hurtling through space which could possibly hit Earth. An example of this was when the comet Shoemaker-Levy collided with Jupiter in 1994.

Some scientists believe that if Jupiter was much bigger, it would be a star. It is made up of the same elements as the Solar System's star, the Sun, hydrogen and helium, plus traces of other elements. Also, Jupiter seems to have its own mini Solar System, with sixteen moons orbiting it, some bigger than Pluto and Mercury. Some of these moons, the four larger ones (Io, Europa, Ganymede and Callisto) are all very different from each other. Io is volcanic, and Europa has oceans of water under a thick layer of ice! In 1979, two space probes, Voyagers 1 and 2 (USA) reached Jupiter and provided us with detailed pictures of the planet and its moons. These probes also visited the three other Gas Giants (Saturn, Uranus and Neptune) before continuing on to float away through distant space. And, just in case there happened to be any alien spaceships flying past Voyager 1 or 2, both had discs on them containing pictures, maps and charts of Earth. They also had records of a 1958 song called Johnny B. Goode by Chuck Berry!