Image of Jupiter taken by the Hubble Space Telescope in 2020. Credit: NASA, ESA, STScI, A. Simon, and M. H. Wong and the OPAL team
Jupiter is the 5th planet from the Sun with an average distance of 5.203 AU or 7.783 x 108 km. It takes 11.86 Earth years to orbit the Sun, and rotates very quickly at a rate of 1 rotation every 9 hours 50 minutes and 28 seconds. It is the largest planet in the Solar System with a mass of 1.899 x 1027 kg or 317.8 Earth masses. It has 80 moons, with 63 having official names given by the International Astronomical Union (IAU). The four largest moons are Ganymede, Callisto, Io, and Europa (also known as the Galilean moons), and these would be considered dwarf planets if they orbited the Sun rather than Jupiter. The average temperature of Jupiter at the cloudtops is about 165 K (−108 °C or −162 °F).
Jupiter can be seen with the naked eye and is one of the brightest objects in the night sky. It is 2.5 times more massive than all the other planets in the Solar System combined. Jupiter has a very thin ring system, discovered by Voyager 1 in 1979. The Great Red Spot is a gigantic storm that has been in existence since at least 1831, possibly even as early as 1665. The storm is large enough to contain 2-3 Earths. Io is the most volcanic body in the Solar System. Europa is completely covered in ice with a hypothesized water ocean beneath it, and is one of the other very few places in the Solar System that has the possibility for life to exist. Ganymede is the largest moon in the Solar System. Io has very active volcanos and lightning has been observed on it as well.
Jupiter has been visited by several spacecraft including Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, Cassini and New Horizons. They discovered a strong magnetic field generated by Jupiter, which is 14 times stronger than Earth's magnetic field.