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Jupiter – Planet · Gas giant
Image: NASA/STSCI (S.T.A.R.S) · Public domain
🪐 Planets · The Giants

Jupiter

Planet · Gas giant

Jupiter is the king of the planets – more than twice as massive as all the other planets combined. It is a ball of mostly hydrogen and helium with colourful cloud stripes and the Great Red Spot, a storm wider than Earth.

  • 139,820 kmAbout 11 Earths would fit side by side across it.
  • 9 h 56 minDay
  • 11.9 yearsYear
🔭 Find it in the sky

Take a closer look

An ocean of metal

Deep inside Jupiter, the crushing pressure squeezes hydrogen into a liquid that conducts electricity like metal. As the planet spins, this sea of liquid metal creates the strongest magnetic field of any planet. If we could see it from Earth, it would look bigger than the full Moon in our sky.

Bigger than a planet

Ganymede, Jupiter’s largest moon, is the biggest moon in the Solar System – wider than the planet Mercury. It is the only moon known to have its own magnetic field, and scientists think a salty ocean is hidden beneath its icy crust. ESA’s JUICE spacecraft is on its way to orbit it.

No ground to land on

Jupiter has no solid surface. A probe falling in would sink through ever thicker, hotter gas until it was crushed. In 1995 NASA’s Galileo spacecraft dropped a small probe into the clouds, and it radioed back measurements for about an hour before it went silent.

Size it up

EarthJupiter

About 11 Earths would fit side by side across it. Both are drawn to the same scale.

How we found out

  1. 1610

    Galileo discovers Jupiter’s four large moons – Io, Europa, Ganymede and Callisto. It proves that not everything goes around Earth.

  2. 1979

    Voyager 1 and 2 discover faint rings and volcanoes on Io.

  3. 1994

    Comet Shoemaker–Levy 9 smashes into Jupiter, leaving dark scars bigger than Earth.

  4. 2016

    NASA’s Juno spacecraft begins orbiting Jupiter.

  5. 2023–24

    ESA’s JUICE and NASA’s Europa Clipper launch to study Jupiter’s icy moons, which may hide oceans.

🤔 Something to wonder about

Could there be life on one of Jupiter’s moons?

See it yourself

One of the brightest “stars” in the sky. Hold binoculars very steady and you can see up to four tiny moons lined up beside it.

Got it?

Mark Jupiter as explored to earn 10 XP.