Jupiter is a gas giant, containing two and a half times the amount of all the other planets in the Solar System combined. It is the largest and most massive planet in our solar system, taking the fifth place from the Sun. The average distance between Jupiter and the Sun is 778 million km (484 million miles) and it completes an orbit every 11.86 years. The rotation of Jupiter is the fastest of all the Solar System planets, completing a rotation on its axis in slightly less than ten hours. Consequently, the planet shape is of an flattened at the poles spheroid. On Jupiter, the equatorial diameter is 9,275 km (5,763 miles).

The atmosphere of Jupiter, spanning over 5,000 km (3,000 miles) in altitude, is composed of approximately 75% hydrogen and 24% helium by mass, with the remaining one percent of the mass consisting of other elements. As Jupiter has no surface, the base of its atmosphere is considered to be where the atmospheric pressure is equal to 1 MPa, or about ten times the surface pressure on Earth. The core region is surrounded by dense metallic hydrogen, which extends outward to about 78% of the radius of the planet. The temperature and pressure inside Jupiter increase steadily toward the core. At the "surface" pressure level is slightly less than 10 times the atmospheric pressure on Earth at sea level, and the temperature is around 67 degree C (52 degree F). At the region where hydrogen becomes metallic the temperature is calculated to be 9,700 degrees C (17,500 degrees F) and the pressure of 200 GPa (about 2 million atm). The temperature at the core boundary is estimated to be 35,700 degrees C (64,300 degrees F) and the interior pressure is roughly 3,000–4,500 GPa. The atmospheric pressure on Earth at sea level is about 100 Kpa.

The most famous feature of Jupiter is the Great Red Spot, a persistent storm located 22 degrees south of the equator, that is larger than Earth. Jupiter has a dust planetary ring system composed of an inner known as the halo, a relatively bright main ring, and an outer fine ring. Jupiter has 67 natural satellites. More of them are less than 10 kilometres in diameter. The four largest moons, known as the "Galilean moons", are Io, Europa, Ganymede, and Callisto. Io is the most volcanically active body in the solar system. Ganymede is the largest moon in the solar system and the only moon known to have its own magnetic field. Beneath the frozen crust of Europa lies a liquid-water ocean with the ingredients for life. Callisto is the third-largest moon in the Solar System and the second largest in the Jovian system.

Between the orbits of the planets Jupiter and Mars the asteroid belt is situated. It consists of a numerous irregularly shaped bodies called asteroids or minor planets. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea.

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