Image: In this photograph (right image), at the bottom left we see Ganymede passing in front of the gaseous monster, Jupiter.
Image credit: NASA.
The planet Jupiter has several amazing features that set it apart from other planets in the solar system. This gas giant is a complex system on its own.
Impressive size: Jupiter is the largest planet in the solar system. Its mass is more than twice that of all the other planets combined. It has a diameter of about 143,000 kilometers, or about 11 times that of Earth.
Turbulent Atmosphere: Jupiter is known for its turbulent and dynamic atmosphere. It features colorful cloud bands and gigantic whirlpools, including the famous Great Red Spot, a massive anticyclonic storm that has lasted for centuries.
Dark Ring System: Although Jupiter's rings are much less dramatic than Saturn's, the planet has a ring system made up of dust particles. These rings are relatively dark and not very visible from Earth.
Major Satellites: Jupiter has more than 70 known moons, including the four Galilean moons: Io, Europa, Ganymede and Callisto. These moons are remarkable for their size and geological diversity, and they harbor some of the most interesting environments in the solar system.
Strong Magnetic Field: Jupiter has an extremely strong magnetic field, about 20,000 times stronger than Earth's. This magnetic field generates intense auroras and influences the environment around the planet.
Complex internal structure: Jupiter is mainly composed of hydrogen and helium, but its internal structure is complex. The planet probably has a rocky core surrounded by a metallic hydrogen envelope and a thick atmospheric layer.
We know 95 natural satellites of Jupiter, including 92 confirmed, including 72 numbered, including 57 named. Jupiter is the planet in the Solar System with the largest number of observed natural satellites. These moons are celestial objects that orbit the giant planet Jupiter and vary in size, composition and characteristics. Jupiter's moons are often categorized by their proximity to the planet and their orbital properties. Jupiter's four largest and best-known Galilean moons are Io, Europa, Ganymede, and Callisto. However, observations and discoveries continue, so it is possible that new moons of Jupiter will be discovered in the future.
Io is the closest moon to Jupiter and the fourth largest moon in the solar system. It is known for its intense volcanic activity, with lava eruptions visible on its surface. Io has a rocky core and a very thin atmosphere composed mostly of sulfur dioxide. Its intense volcanic activity is due to the effect of tidal forces generated by the gravitational pull of Jupiter.
Europa is one of Jupiter's Galilean moons and is slightly smaller than Earth's Moon. It is mostly made up of rock and ice, and is considered one of the most promising places to search for extraterrestrial life in the solar system. Observations have revealed the presence of a subterranean ocean of liquid water below its frozen surface, with potential interaction between the water and the rocky core.
Ganymede is the largest moon in the solar system and is larger than the planet Mercury. It has a crust of ice, a mantle of rocks and a metallic core. Ganymede is the only moon known to generate its own magnetic field, possibly due to its rotating liquid core.
Callisto is also a Galilean moon of Jupiter and is the second largest moon in the solar system. It has a crust of ice, a mantle of rocks and a rocky core. Callisto is Jupiter's oldest moon, with a surface dotted with impact craters, indicating that it has undergone little geological change over time.
1972: Pioneer 10 (USA) was an unmanned space probe launched by NASA on March 2, 1972. Its main purpose was to study Jupiter up close and to transmit data and images of the planet. Pioneer 10 performed a flyby of Jupiter on December 3, 1973, passing at a distance of about 130,000 kilometers from the planet's surface. The probe provided the first close-up images of Jupiter, revealing details of the atmosphere, cloud bands and the Great Red Spot.
1973: Pioneer 11 (USA) was an unmanned space probe launched by NASA on April 6, 1973. Its main purpose was to study Jupiter and its moons up close, and to continue its journey beyond Jupiter to other regions of the solar system.
1977: Voyager 1 (USA) was launched by NASA on September 5, 1977. Its original purpose was to study the giant planets of the solar system, including Jupiter and Saturn. Voyager 1 performed a flyby of Jupiter in March 1979, providing detailed images of the planet, its moons and its turbulent atmosphere. The probe captured remarkable images of Jupiter's Great Red Spot and discovered active volcanoes on the moon Io. After its flyby of Jupiter, Voyager 1 continued its journey outside the solar system and became the first probe to reach interstellar space in 2012. Voyager 1 continues to send data from interstellar space, albeit at an extremely distant distance from Earth.
1977: Voyager 2 (USA) was launched by NASA on August 20, 1977, shortly before Voyager 1. Its main mission was to study Jupiter, Saturn, Uranus and Neptune, making it the only probe to have visited these four giant planets. Voyager 2 flew past Jupiter in July 1979, capturing detailed images of the planet, its moons and rings. The probe also studied Jupiter's ice moons, including Europa and Ganymede, and discovered some interesting geological features. After Jupiter, Voyager 2 continued its mission and flew by Saturn in 1981, Uranus in 1986 and Neptune in 1989, providing valuable data on these planets and their moons. Voyager 2 continues to operate and send data from interstellar space, even further from Earth than Voyager 1.
1989: Galileo (United States and Europe) was a space probe launched by NASA on October 18, 1989. Its main objective was to study Jupiter, its moons and its environment for an extended period. Galileo used gravitational assistance from Earth and Venus to reach Jupiter in December 1995. Once in orbit around Jupiter, Galileo began to study the planet, its moons and its magnetosphere. The probe provided detailed images of Jupiter, revealing features of its turbulent atmosphere, including the Great Red Spot. Galileo also discovered active volcanoes on the moon Io, potential lakes and oceans on Europa, chaotic terrain on Ganymede, and craters on Callisto. The Galileo mission lasted more than 14 years, well beyond its originally planned lifespan. The mission ended in September 2003 with a controlled descent of Galileo into Jupiter's atmosphere to avoid contamination of potentially habitable moons.
1990: Ulysses (USA and Europe) was launched on October 6, 1990 using NASA's Space Shuttle Discovery. The probe used gravitational assistance from Jupiter to change orbital inclination and gain a never-before-seen view of the Sun's polar regions. Ulysses was the first mission to study the poles of the Sun in polar orbit, providing unique and in-depth observations of the magnetic field, solar wind and energetic particles. The mission also collected data on the interplanetary environment, including magnetic fields, cosmic dust and cosmic radiation. Ulysses flew past Jupiter in February 1992, using gravitational assistance to adjust its orbit and head toward the Sun's polar regions. The Ulysses mission lasted more than 18 years, well beyond its originally planned lifespan. The probe ceased operations in June 2009, after providing a significant amount of data on the Sun and the interplanetary medium.
1997: Cassini-Huygens (United States and Europe) was launched on October 15, 1997 and consisted of two elements: the Cassini probe and the Huygens landing module. The Cassini probe was primarily responsible for studying the planet Saturn and its moons, while the Huygens landing module was designed to land on Saturn's moon, Titan. Cassini performed a flyby of Jupiter in 2000, using the planet's gravity assist to reach Saturn. After arriving on Saturn in 2004, Cassini embarked on a mission to thoroughly explore the planet, its rings and its many moons. Cassini provided detailed images and data of Saturn, revealing details about its atmosphere, storms, intricate rings and numerous satellites. In December 2004, the Huygens landing module separated from Cassini and successfully landed on Titan in January 2005, becoming the first probe to land on a moon on another planet in the solar system outside Earth. The Cassini-Huygens mission ended in September 2017 with a controlled dive of Cassini into Saturn's atmosphere, ending its operational mission. The data collected by Cassini-Huygens has greatly improved our understanding of Saturn, its moons, its rings, and the environment of the Saturnian system.
2011: Juno (USA) was launched on August 5, 2011 from Cape Canaveral, Florida. Its main objective is to better understand the origin and evolution of Jupiter, by studying its atmosphere, its interior structure, its magnetic field and its composition. Juno uses a polar orbit around Jupiter, which allows it to study the planet up close and collect detailed data. The mission has an expected lifetime of 20 months, during which Juno performs close flybys of Jupiter at a relatively close distance from the planet. Juno is equipped with sophisticated scientific instruments, including cameras, spectrometers and particle detectors, which collect data on Jupiter's atmosphere, composition and internal structure. Juno's science goals include studying Jupiter's enormous atmospheric storm, known as the Great Red Spot, as well as searching for water and clues to planetary formation processes. Juno also helped map Jupiter's magnetic field and collect data on its aurora. The Juno mission has been extended several times and continues to operate and collect valuable data on Jupiter.
2023: JUICE (JUpiter ICy moons Explorer). This mission of the European Space Agency (ESA) is intended to explore the moons of Jupiter, in particular Ganymede, Callisto and Europa, to better understand their potential habitability and their geological evolution.
2024: Europa Clipper (United States). This mission is designed to study the icy moon of Europa, one of Jupiter's moons, by performing close flybys to analyze its atmosphere, surface and composition.