Jupiter is the largest planet in the Solar System and the fifth from the Sun. It is a gas giant. Jupiter is a colossal and fascinating world, rich with mysteries and dramatic features. Its immense size, swirling clouds, powerful storms, including the famous Great Red Spot, and diverse moon system make it one of the most interesting objects in the Solar System to study.

1. 1. Size and Composition

• • • Diameter: Jupiter has a diameter of about 139,820 km (86,881 miles), making it 11 times the diameter of Earth and more than 1,300 times Earth’s volume.
    • Mass: It is about 318 times more massive than Earth, but it’s primarily composed of hydrogen and helium, like a small star.
    • Composition: Jupiter lacks a solid surface and is mostly made of gas. The planet likely has a small, rocky core surrounded by a thick layer of metallic hydrogen and an outer layer of molecular hydrogen.

 

1. 2. Orbit and Rotation

• • • Orbit around the Sun: Jupiter takes about 12 Earth years to complete one orbit around the Sun.
    • Day length: Despite its size, Jupiter has the shortest day of any planet, with one full rotation taking just 9.9 hours. This rapid rotation flattens the planet slightly at the poles and bulges it at the equator.

 

1. 3. Atmosphere and Weather

• • • Jupiter’s atmosphere is primarily hydrogen (90%) and helium (10%), with traces of methane, ammonia, water vapor, and other compounds. These elements form the planet’s thick cloud layers.
    • Cloud bands: Jupiter’s atmosphere is marked by colourful cloud bands that run parallel to its equator. These bands consist of ammonia clouds and are driven by powerful jet streams that blow in opposite directions.
    • Great Red Spot: One of Jupiter’s most recognizable features is the Great Red Spot, a gigantic storm larger than Earth that has been raging for at least 300 years. The storm is a high-pressure region in the atmosphere, and while it’s slowly shrinking, it remains a significant feature.
    • Jupiter’s atmosphere also contains massive, fast-moving storms and lightning flashes much more powerful than those on Earth.

 

1. 4. Magnetic Field

• • • Jupiter has the strongest magnetic field of any planet in the Solar System, about 20,000 times stronger than Earth’s. This powerful magnetosphere extends millions of kilometres into space, creating intense radiation belts and trapping charged particles.
    • The magnetic field creates stunning auroras at the planet’s poles, similar to the Northern and Southern Lights (Aurora Borealis and Aurora Australis) on Earth, but far more powerful.

 

1. 5. Moons

• • • Jupiter has 92 known moons, the largest number of any planet in the Solar System (as of 2024). The four largest moons are called the Galilean moons: Io, Europa, Ganymede, and Callisto, discovered by Galileo in 1610.
    • Io: The most volcanically active body in the Solar System, with hundreds of active volcanoes.
    • Europa: Has a smooth, icy surface, with evidence of a subsurface ocean, making it a strong candidate for the potential existence of life.
    • Ganymede: The largest moon in the Solar System, even bigger than Mercury, with its own magnetic field.
    • Callisto: A heavily cratered moon that also may harbour an underground ocean.

 

1. 6. Rings

Jupiter has a faint ring system, unlike the bright rings of Saturn. Jupiter’s rings are composed mainly of dust particles ejected by its moons during impacts from meteoroids.

 

1. 7. Interior

• • • Jupiter’s internal structure is not fully understood, but it is believed to have a dense, rocky core surrounded by layers of metallic hydrogen and liquid hydrogen.
    • The immense pressure inside Jupiter turns hydrogen into a metallic state, which is believed to generate its strong magnetic field.

 

1. 8. Exploration

• • • Jupiter has been explored by several spacecraft, including Pioneer 10, Voyager 1 and 2, Galileo, and Juno.
    • Juno has been orbiting Jupiter since 2016, studying its atmosphere, magnetic field, and deep interior to provide more insights into the planet’s structure.
    • Future missions like Europa Clipper will focus on Jupiter’s moon Europa, searching for signs of life beneath its icy surface.

 

1. 9. Jupiter’s Role in the Solar System

• • • Jupiter plays a critical role in the Solar System due to its immense gravity. It acts as a shield for Earth by deflecting or capturing many comets and asteroids that might otherwise strike the inner planets.
    • Its strong gravitational influence also helps shape the orbits of other objects in the Solar System, including some asteroids and moons.

 

1. 10. Interesting Facts

• • • Radiation: Jupiter emits more heat than it receives from the Sun, likely due to slow gravitational contraction and leftover heat from its formation.
    • Potential for Life: While Jupiter itself is unlikely to support life due to its hostile environment, its moons, particularly Europa, are considered some of the best candidates for finding life beyond Earth.