What Is the 5th Planet in Our Solar System
The 5th planet in our solar system is Jupiter, the largest planet in the solar system. It is a gas giant located beyond the asteroid belt, orbiting the Sun at an average distance of about 5.2 astronomical units. NASA and ESA list Jupiter as the fifth planet from the Sun in current planetary catalogs NASA Solar System Overview.
Jupiter has a mass roughly 318 times that of Earth and a diameter about 11 times larger than Earth's equator. Its equatorial radius is approximately 71,492 kilometers, making it the most massive planet in the solar system. The planet's gravity at the cloud tops is about 2.5 times Earth's surface gravity NASA Jupiter Facts.
Jupiter Composition, Atmosphere, and Interior Structure
Atmospheric Composition and Bands
Jupiter's atmosphere is primarily composed of hydrogen and helium, with trace amounts of methane, ammonia, and water vapor. Visible cloud bands form from strong east-west winds and convection, with zones of high pressure and belts of low pressure. The Great Red Spot, a persistent anticyclonic storm, has been observed for centuries and spans wider than Earth NASA Great Red Spot.
Interior and Magnetic Field
Jupiter likely has a dense core surrounded by metallic hydrogen and an outer molecular hydrogen envelope. Its magnetic field is the strongest of any planet in the solar system, generated by electric currents in the metallic hydrogen layer. The magnetosphere traps charged particles and drives intense radiation belts around the planet.
Missions to Jupiter and Current Exploration
Key NASA and ESA Missions
NASA's Juno spacecraft entered Jupiter orbit in 2016 and continues to study the planet's gravity field, magnetic field, and deep atmosphere NASA Juno Mission. ESA's JUICE (Jupiter Icy Moons Explorer) launched in 2023 and is en route to Jupiter, targeting Ganymede, Callisto, and Europa ESA JUICE.
Future Observations and Data
Ground-based observatories and upcoming missions will continue to refine measurements of Jupiter's atmosphere, rings, and moons. Data from Juno and JUICE support long-term studies of gas giant formation and evolution within our solar system and for exoplanet comparisons.