Jupiter
Jupiter is the fifth planet from the Sun and is the largest one in the solar system. If Jupiter were hollow, more than one thousand Earths could fit inside. It also contains more matter than all of the other planets combined. Jupiter has 28 known satellites, four of which were observed by Galileo in 1610. These satellites are named Callisto, Europa, Ganymede and Io. There is a ring system and is totally invisible from the Earth. The rings were discovered in 1979 by Voyager 1. Jupiter’s atmosphere is somewhat like the Sun. It is composed mainly of hydrogen and helium. Jupiter contains 90% hydrogen and 10% helium, with small amounts of methane, ammonia, water vapour and other compounds. Within Jupiter, the pressure is so enormous that the hydrogen atoms are broken up and the electrons are freed so that the remaining atoms are bare protons. This results in hydrogen becoming metallic. Colourful bands, atmospheric clouds and storms describe Jupiter’s weather systems. The cloud patterns change within hours or days.
