Jupiter

As the solar system’s largest planet, Jupiter plays a key role in shaping planetary orbits and shielding Earth from debris.

Telescopic picture of Jupiter

Introduction

Jupiter is the largest planet in our solar system and one of the most fascinating. It's known for its rapid rotation, dynamic atmosphere, iconic Great Red Spot, and complex system of moons, rings, and magnetosphere. Although it’s mostly made of gas, Jupiter holds clues to how the solar system formed and evolved.

Potential for Life

The planet is named after Jupiter, the king of the gods in Roman mythology. Its moons are mostly named after characters associated with Jupiter (or Zeus in Greek mythology). Jupiter itself is unlikely to support life due to its high pressure, intense radiation, and extreme temperatures. However, Europa, one of Jupiter’s moons, may have a subsurface ocean beneath its icy crust. This ocean could harbor microbial life, making Europa a prime target for astrobiology missions like NASA’s Europa Clipper.

Properties

Property	Information
Size and Distance	Radius: 69,911 km (11x wider than Earth) Volume: Could fit over 1,300 Earths inside Distance from Sun: ~778 million km (5.2 AU) Sunlight travel time: ~43 minutes
Orbit and Rotation	Day length: ~9.9 Earth hours (shortest day in the solar system) Year length: ~12 Earth years (4,333 Earth days) Axial tilt: 3°, so Jupiter has very mild seasons
Moons	Jupiter has 95 confirmed moons, including the four Galilean moons, discovered in 1610: Io – The most volcanically active object in the solar system Europa – Icy crust, likely with a liquid water ocean beneath Ganymede – Largest moon in the solar system (larger than Mercury) Callisto – Old, cratered surface; may also have a subsurface ocean These moons are geologically diverse and of great scientific interest.
Rings	Jupiter has a faint ring system, discovered by Voyager 1 in 1979. The rings are made of dust particles and are best seen when backlit by the Sun. They're thought to form from meteoroid impacts on the planet’s small inner moons.

Formation

Jupiter formed about 4.6 billion years ago, shortly after the Sun. It captured most of the gas and dust left over from solar formation, becoming more massive than all the other planets combined. Its composition is similar to the Sun – mainly hydrogen and helium – but it wasn’t massive enough to become a star.

Internal Structure

• Outer layers: Hydrogen and helium gases

• Middle layer: Liquid hydrogen

• Inner layer: Metallic hydrogen, which conducts electricity and drives the magnetic field

• Core: Possibly large and “fuzzy” – a mixture of heavy elements and hydrogen, not clearly defined

The Juno spacecraft has provided data suggesting Jupiter’s core is partially dissolved and extends farther than once thought.

Surface

Jupiter has no solid surface. The visible “surface” is the top of the cloud layer. Below that, pressure and temperature increase rapidly. A spacecraft trying to enter Jupiter would be destroyed by crushing pressure and hea.

Atmosphere

• Composed of hydrogen (H₂), helium (He), and trace gases like methane (CH₄), ammonia (NH₃), and water vapor (H₂O)

• Has bands of clouds: dark belts and lighter zones moving in opposite directions due to strong jet streams

• Home to massive storms, including the Great Red Spot, which is larger than Earth and has lasted for over 300 years

• Cloud layers may be made of ammonia ice, ammonium hydrosulfide, and water ice/vapor

Weather Systems

• Wind speeds can exceed 539 km/h near the equator

• Cyclones and anticyclones form at both poles in geometric patterns (octagon in the north, pentagon in the south)

• The Great Red Spot reaches depths of about 500 km below the clouds

• Jet streams reach down to 3,200 km, showing deep atmospheric structure similar to Earth's ocean circulation

Magnetosphere

Jupiter has the strongest magnetic field of any planet – 16 to 54 times stronger than Earth's.

• Its magnetosphere extends up to 3 million km toward the Sun and more than 1 billion km away on the night side (a magnetotail that reaches past Saturn)

• Traps high-energy particles, creating dangerous radiation belts

• Causes spectacular auroras at the poles, even stronger than those on Earth

• Radiation is strong enough to damage or destroy unshielded spacecraft

Scientific diagram of Jupiter

Summary

Jupiter is the largest planet in the solar system, made mostly of hydrogen and helium with no solid surface. It spins rapidly, creating strong jet streams and massive storms like the Great Red Spot. Jupiter has 95 moons, including Europa, which may have an ocean that could support life. It has faint dust rings and a powerful magnetic field—the strongest of any planet—which creates intense radiation and bright auroras. Formed over 4.5 billion years ago, Jupiter holds clues to how the solar system developed.