Each time you look up to the sky and see a star you are looking at a sun in another galaxy. If you were on another planet looking back at our solar system, you would see our sun as a star.

It’s believed that every sun has planets orbiting it. Our Milky Way galaxy has more planets than it has stars. In our solar system we have eight planets: Mercury, Venus, Earth, and Mars are the inner rocky planets. Jupiter and Saturn are the outer gas giants.

Uranus and Neptune are the outer ice giants. In recent years, astronomers have designed a new class called the “dwarf planets.” These are smaller worlds, not quite big enough to be considered a standard planet, and include Pluto. Jupiter is the fifth planet from the sun.


Jupiter Statistics:

  • Distance from Sun: 483.8 million mi
  • Rings: 4
  • Radius: 43,441 mi
  • Polar Diameter: 133,709 km
  • Orbital period: 12 years
  • Mass: 1.90 × 10^27 kg (318 Earths)
  • Length of day: 0d 9h 56m
  • Surface area: 23.71 billion mi²
  • Effective Temperature: -148 °C
  • Moons: (79, including (Io, Europa, Ganymede & Callisto)
  • First Recorded: 7th-8th Century BCE by Babylonian astronomers

How did Jupiter get its name:

Jupiter was named after the Roman king of the gods. It’s the fifth planet from the sun in our solar system and the largest planet of all. To give you an idea of how big Jupiter is, you could line up 11 Earths, side-by-side just to stretch from one side of Jupiter to the other.

Jupiter’s mass is incredibly large as well and it would take 317 Earths to match the mass of Jupiter.


Around 4.5 billion years ago our solar system settled into the configuration that we know today. Jupiter settled in its position as the fifth planet about 4 billion years ago.

Gravity played a major part in creating the planets as it pulls dust and swirling gas together. Jupiter is one of the gas giants and it’s believed that it took most of the mass that was left after the sun was formed.

This is why Jupiter has over twice the materials of all of the other bodies in the solar system combined. Jupiter has the same ingredients as our own sun and if it had grown just a bit larger it would have ignited to become a second sun in our solar system.

Structure and Surface:

Jupiter is made up of a composition of mostly hydrogen and helium that is very similar to our sun. As a gas giant you have to go deep into the atmosphere to find that temperature and pressure has increased so much that it has compressed the hydrogen gas into a liquid form.

That hydrogen liquid gives Jupiter the largest ocean in the entire solar system. Scientists believe that nearing halfway to Jupiter’s center the pressure is so great that electrons are squeezed away from the hydrogen atoms.

This would put the liquid into a condition where it is electrically conductive, like metals. It’s thought that the fast rotation of the planet is enough to drive electrical currents in this area so that it generates the incredibly powerful magnetic field.

Scientists speculate that Jupiter’s interior is made up of three regions: a rocky core with a mass of between 12-45 times the size of the Earth that is made-up of mostly iron and silicate minerals.

It’s thought to be as hot as possibly 90,032 F/50,000 degrees C. The second region makes up most of Jupiter’s mass and it surrounds the core with a layer of liquid hydrogen that is electrically conductive.

The third region is made up of ordinary hydrogen with some helium traces and this transitions to the atmosphere of the planet.

Jupiter Structure

Jupiter is a gas giant and as such, doesn’t really have what we would call a real “surface.” The planet is made up of gases and liquids that are constantly swirling around.

If we tried to send a spacecraft to Jupiter there wouldn’t be a place for it to land. A spacecraft would also be unable to fly due to the extreme temperatures and pressures that would crush, vaporize, and melt the spacecraft.

Jupiter’s storms are incredibly huge and they seem to be created on the edges of the darker and lighter horizontal bands of the planet.

The biggest storm is The Great Red Spot, and it’s nearing 25,000 km across. The Great Red Spot has been going on for centuries and is big enough to hold two Earths

Scientists have discovered that Jupiter actually gives off more energy than it receives from the sun.

They have figured out that Jupiter is so large that its mass exerts such an incredible gravitational force on itself that it compresses or squashes the planet. This process makes such a great quantity of heat that it becomes overloaded and throws it out into space.

As the fifth planet in the solar system, Jupiter is a tad more than five times the distance of the sun than Earth is.

A year for a planet is the amount of time that it takes to complete an orbit around the sun, and for Jupiter this takes 4,333 Earth days.

A day for a planet is the amount of time it takes to make one entire rotation and Jupiter sets the record in the solar system for a bit less than ten hours. The incredibly fast rotation that Jupiter has is what makes the bulge near its equator.

This bulge also makes it look less like a sphere. The sheer size of the planet and the fact that it’s mostly made up of gas, without a solid body, has created an odd situation in that not all parts of Jupiter rotate at the same time.

The rotation of Jupiter’s polar atmosphere rotates five minutes slower than that of the equator.

Atmosphere. Magnetosphere, and Moon Status:

Scientists have had a difficult time trying to define Jupiter’s atmosphere. This is due to the fact that its outer zone of gas changes into a liquid layer as you get closer into the planet.

They estimate that the atmospheric pressure on the “surface” of Jupiter is around ten times that at sea level on Earth.

The gases in the atmosphere are almost the same that make up our sun: 90% hydrogen and 10% helium.

There are a lot of colors in Jupiter’s cloud bands and spots, and may be plumes of sulfur and phosphorus-containing gases that rise from the intense heat of the interior of the planet. It’s thought that Jupiter has three distinct cloud layers that make up its “skies.”

When added together these cloud layers expand to around 44 mi/71 km. The top cloud layer is most likely made up of ammonia ice, the middle layer is likely to consist of ammonium hydrosulfide crystals, and the innermost layer may be vapor and water ice.

Jupiter’s incredibly fast rotation allows it to complete a rotation every 10 hours and this creates strong jet streams that separate the clouds into bright areas and dark belts for long stretches.

The “spots” on Jupiter are actually massive storms that can live for many years. As smaller storms form they are often engulfed by larger ones.

The prevailing winds can reach up to 335 mph/539 kph at the equator. The most well-known is The Great Red Spot which is a swirl of oval clouds twice as wide as our Earth.

We know that we have been observing this spot for over 300 years. Most recently three smaller oval storms merged together to form the Little Red Spot which is half the size of The Great Red Spot.

Scientists continue to study Jupiter and yet are unsure if these planet-circling bands and ovals are deeply rooted or shallow to the planet’s interior.

Jupiter has 79 confirmed moons and scientists have divided them up into three groups. The inner moons are those that are closest to Jupiter; the Galilean moons, Galileo Galilei; and Outer moons, these are the smallest and most distant from Jupiter.

The biggest of Jupiter’s moons is Ganymede and it’s also the biggest moon in the solar system. An interesting thing about Ganymede is that even though it’s a moon, it’s larger than the planet Mercury.

Europa is one of the large moons that many scientists are interested in because they believe that there might be a liquid-water ocean beneath the frozen crust.

Jupiter has other large moons including Callisto and Io. It’s thought that Jupiter has enough moons that it could be a miniature solar system.

Jupiter has a powerful magnetic field that balloons 600,000 to 2 million mi/1-3 million km toward the sun.

This is 7-21 times the diameter of Jupiter itself and the field tapers into a tadpole-shaped tail that extends out behind the planet more than 600 million mi/1 billion km.

This extension goes as far as the orbit of Saturn. The intense magnetic field of Jupiter is 16-54 times as powerful as the magnetic field of Earth and rotates with the planet, picking up any particles that have an electric charge.

The magnetic field traps swarms of charged particles near the planet and then speeds them up to extremely high energies, creating high intensity radiation that bombards the innermost moons.

It’s this radiation that can cause a lot of damage to any spacecraft and why much of the exploration of Jupiter is often done from a distance. The magnetic field does create some of the most beautiful aurorae at its poles.

In 1979 the NASA Voyager 1 spacecraft discovered a ring around Jupiter. This discovery was a surprise because they are made up of small dark particles that are almost impossible to see except when they are backlit by the sun.

Data sent from the Galileo spacecraft confirmed that the ring of Jupiter is probably formed by dust kicked up as meteoroids crash into the many moons that orbit Jupiter.

Could Life Exist on Jupiter?

The environment within Jupiter is not conducive to life as we know it. The pressures and temperatures, along with materials of Jupiter are too volatile and extreme for life to adapt to.

While Jupiter itself can’t be a location for life, some of its moons could be. Europa is thought to be one of the likeliest places that life may be found anywhere in our solar system so far.

Evidence is showing that there is a huge ocean beneath Europa’s crust with liquid water that could possible support life.

Interesting Information:

Jupiter’s intense magnetic field is thought to be a contributing factor in protecting Earth from a worse bombardment of meteorites.

As meteorites enter the solar system from the exterior areas they are caught up by Jupiter before they have a chance to get close to Earth.

Space Missions to Jupiter:

Jupiter has been studied for many years, with the first observations detailed in 1610 by Galileo Galilei. Since then, we have sent a number of spacecraft, probes, and orbiters to take detailed images and collect data from Jupiter.

In the 1970’s we sent Pioneer 10 and 11 as well as Voyager 1 and 2 for flybys of Jupiter. The Galileo spacecraft orbited the gas giant and sent a probe into the atmosphere.

When Cassini was heading to Saturn it took an array of images of Jupiter, and New Horizon did the same as it headed to Pluto and the Kuiper Belt. In 2016 NASA’s June spacecraft arrived in the Jovian system to study the gas giant in orbit.

Galileo Galilei

  • 1610: Galileo Galilei creates his Jupiter observations.
  • 1973: Pioneer 10 is the first spacecraft to get through the asteroid belt and does a flyby passed Jupiter.
  • 1979: Voyager 1 and 2 missions find the faint rings of Jupiter, a number of new moons that were not know about before and the fact that Io has volcanic activity.
  • 1992: Ulysses mission does a swing by so that the gravity bent the flight path of the spacraft allowing the probe to a last orbit that took it over the south and north poles of the sun.
  • 1994: Comet Shoemaker-Levy 9 enters Jupiter’s atmosphere, breaks up and then crashes into Jupiter.
  • 1995-2003: The Galileo spacecraft places a probe into the atmosphere of Jupiter to accomplish observations of the planet and its rings and moons.
  • 2000: Cassini’s close approach to Jupiter enables it to take full color photos of Jupiter.
  • 2007: NASA’s New Horizons spacecraft takes pictures of Jupiter on its way to Pluto. The pictures offer new information and data on the atmospheric storms on Jupiter, it’s rings, Io’s volcanic activity and the ice on Europa.
  • 2016: NASA’s Juno spacecraft arrives at Jupiter and conducts studies of the planets magnetosphere, atmosphere, and deep structure to help understand Jupiter’s evolution and origin.

Facts about Jupiter for Kids:

  • If Jupiter had been 80 times more massive it would have become our second sun in the solar system.
  • Jupiter holds the title of being the solar system’s fourth brightest object.
  • Jupiter’s clouds are made up of mostly ammonia crystals, sulfur and mixtures of both of these.
  • As asteroids and comets have impacted Jupiter they kick up dust particles that have created a very faint ring around Jupiter.
  • The discovery of Jupiter’s 4 moons by Galileo was the first proof that the Earth was not the center of the universe and evidence that planets orbited the sun.
  • We can only see five planets with the naked eye and Jupiter is one of them.

Pop Culture:

Jupiter has made a presence in many television shows, movies, comics, and video games. In the science fiction “Jupiter Ascending” it was the main destination. Jupiter’s moons have also been noted in “Cloud Atlas, Futurama, Power Rangers, and Halo.”

You might remember “Men in Black” when Will Smith, playing Agent J, comments that he thought his teacher was from Venus and Tommy Lee Jones, playing Agent K, corrects him to say that she was really from one of Jupiter’s Moons.

In the movie “2010: The Year we Make Contact,” Jupiter was ignited to become the second sun in our solar system and its moon Io was to be left alone to allow life to progress.