Jupiter

Jupiter is the largest planet in the solar system and the fifth from the Sun. It belongs to the class of planets known as gas giants, meaning it consists largely of hydrogen and helium and has no solid surface to stand on like Earth does.

Its mass is several hundred times that of Earth and exceeds that of all other planets combined. Jupiter is easily visible to the naked eye at night and is one of the brightest objects in the sky. For this reason, early peoples, including the Babylonians and Greeks, recorded observations of it thousands of years ago.

Structure and Atmosphere

The atmosphere of Jupiter appears in bands of different colors, formed by strong high-altitude winds and storms composed of ammonia and other substances. The most famous feature is the Great Red Spot, an enormous hurricane that has persisted for centuries. The size of this storm has varied and has been observed to shrink in recent decades.

Jupiter rotates very rapidly, one of the fastest among planets: its day lasts about ten hours. It takes approximately 12 Earth years to orbit the Sun. This rapid rotation causes the planet to bulge at the equator and flatten at the poles.

Moons and Rings

Jupiter has a very large number of moons, with new ones continually discovered by scientists. The four largest—Io, Europa, Ganymede, and Callisto—are called the Galilean moons, having been observed by Galileo Galilei through a telescope in 1610. Ganymede is the largest moon in the entire solar system. Europa is thought to have a subsurface ocean of liquid water beneath its ice, making it a significant target in the search for life. Jupiter also has a faint ring system, though not as prominent as that of Saturn.

Magnetic Field and Exploration

Jupiter has an extremely powerful magnetic field that creates an intense radiation environment hazardous to electronic instruments. Several space probes have visited it, including Pioneer and Voyager, which flew past, and Galileo and Juno, which entered orbit around the planet. Juno, which reached Jupiter in 2016, has focused on studying the planet's internal structure, magnetic field, and atmospheric dynamics.