Jupiter

Jupiter and its moons were among the objects seen by the Italian astronomer, Galileo Galilei, when he turned one of the first telescopes to the heavens in 1609.

We got our first close ups of Jupiter and Saturn when the "Pioneer" spacecraft sped by in the 1970's.

At the end of the decade, the two "Voyager" spacecraft followed, and returned spectacular images.

Jupiter, second largest object in our solar system after the Sun, has no solid surface.

Made largely of hydrogen and helium, we think it has a core of liquid metallic hydrogen.

The Voyagers showed us clouds in detailed turbulent motion, including timelapse movies of the "Great Red Spot," which Galileo had first seen more than 300 years before...

Looking back on the dark side of the planet, we saw lightning flash deep down in the clouds.

The astronomers assumed there must be thunderstorms and water vapor in turbulent upward motion, just like down here on earth.

At its core, Jupiter is 20,000 degrees Kelvin. Like Saturn, it generates more heat in its interior through gravitational compression than it receives from the Sun.

Voyager discovered volcanoes on Jupiter's moon Io, making it one of only 4 volcanically-active bodies in the solar system.

Stained yellow and red with sulphur, io was inevitably compared to pizza!

But all 4 Galilean satellites-Io, Europa, Ganymede and Callisto-provided hints of unusual processes at work...

And voyager discovered that Jupiter, like Saturn, also has rings.

Torrence Johnson
Project Scientist, Galileo
Jet Propulsion Laboratory, NASA/Caltech

Until you got beyond the asteroid belt the temperatures weren't low enough to allow the condensation of the more volatile materials. Once you got to the point where you could condense water, wow, you get another big admixture of mass immediately.

So a typical body that condenses just after you get to the point where you can have, uh, frozen water is a body that's about twice as massive as one you've got just inside the water line.

In addition to that you've got all this extra gas and dust floating around. And the larger planets started, when they started forming, they grabbed even more of this, and they've got enough gravity that they can grab onto all this material out there, including the gases hydrogen and helium. And so you get these massive gassy bodies with icy worlds around them.

Revolution

Rotation

Radius

11.86 Earth years

9.8 Earth hours

71,492 km

Distance From the Sun

Mass

Density

778,412,010 km

1,898.7 x 1027 grams

1.33 gm/cm3

Mean Cloud Temperature

Moons

Atmosphere

-121C

17: Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope, and S/1999 J 1

hydrogen, helium and trace elements

Rings

Scientists believe that the formation of Jupiter's rings is from the dust particles given off when meteoroids crash into the surface of Jupiter's four inner moons. Jupiter has three rings consisting of a main ring, a halo inner ring and a third ring. Recent pictures from the Galileo spacecraft show that this third ring known as the Grossamer ring is really composed of two rings with one ring embedded in the other.

Jupiter and its moons were among the objects seen by the Italian astronomer, Galileo Galilei, when he turned one of the first telescopes to the heavens in 1609.

We got our first close ups of Jupiter and Saturn when the "Pioneer" spacecraft sped by in the 1970's.

At the end of the decade, the two "Voyager" spacecraft followed, and returned spectacular images.

Jupiter, second largest object in our solar system after the Sun, has no solid surface.

Made largely of hydrogen and helium, we think it has a core of liquid metallic hydrogen.

The Voyagers showed us clouds in detailed turbulent motion, including timelapse movies of the "Great Red Spot," which Galileo had first seen more than 300 years before...

 

Torrence Johnson
Project Scientist, Galileo
Jet Propulsion Laboratory, NASA/Caltech

The Great Red Spot is a massive storm system in the Jupiter atmosphere. And it probably has a structure very similar to a hurricane in general, which is that it probably has a rising column of atmosphere in the center of it with sort of a spreading out layer on top of that.

Looking back on the dark side of the planet, we saw lightning flash deep down in the clouds.

The astronomers assumed there must be thunderstorms and water vapor in turbulent upward motion, just like down here on Earth.

At its core, Jupiter is 20,000 degrees Kelvin. Like Saturn, it generates more heat in its interior through gravitational compression than it receives from the Sun.

Voyager discovered volcanoes on Jupiter's moon Io, making it one of only 4 volcanically-active bodies in the solar system.

Stained yellow and red with sulphur, Io was inevitably compared to pizza!

But all 4 Galilean satellites-Io, Europa, Ganymede and Callisto-provided hints of unusual processes at work...

And Voyager discovered that Jupiter, like Saturn, also has rings.

WANT TO LEARN MORE?
Missions:
 • Galileo Mission to Jupiter
 • Jupiter Millennium Flyby
Recent Articles:
 • Volcanic Moon Io Wears Sulfur-rich "Snow"
 • Galileo Sees Ammonia Ice Clouds On Jupiter
 • Cassini Snaps Jupiter's Red Spot
 • Giant Storms Collide on Jupiter
 • Scientists show Jovian moon Io's mantle is similar to Earth
 • First Image of Jupiter from Cassini Spacecraft
 • Travel Guide Site Follows Spacecraft to Jupiter
Additional Links:
 • JPL's Solar System Exploration
 • The Nine Planets
 • Views of the Solar System
 • Windows to the Universe