JUPITER
Jupiter is the giant of our solar system — a huge, stormy world so big that all the other planets could fit inside it twice. Jupiter is a giant ball of swirling gas, mostly hydrogen and helium, with no solid ground anywhere. It has more than 100 moons, four faint dust rings, and a famous giant storm called the Great Red Spot. Jupiter is also one of the brightest things in our night sky — you can find it tonight, without a telescope. Keep reading to find out more amazing things about the king of the planets.
For teachers: free lesson plans, slide decks & worksheets →
Jupiter is the largest planet in our solar system and the fifth planet from the Sun. It is a gas giant made mostly of hydrogen and helium, with no solid surface. Jupiter has colourful cloud stripes, a giant storm called the Great Red Spot, faint rings, and more than 100 confirmed moons.
Jupiter often looks like a very bright “star” in the sky — but it doesn’t twinkle the way real stars do. Ask an adult to help you use a free sky-map app (like Stellarium or SkySafari), then look for Jupiter after sunset. You might be looking at the biggest planet in the whole solar system.
📋 Jupiter Quick Facts
- TypeGas giant
- Position from Sun5th planet
- Average distance from Sun778.5 million km (484 million mi)
- Day length9 hours 56 minutes
- Year length11.86 Earth years
- Mass318 × Earth’s mass
- Radius69,911 km (43,441 mi) — 11.2 × Earth’s radius
- Cloud-top gravity24.79 m/s² (about 2.5 × Earth’s gravity)
- AtmosphereMostly hydrogen (~90%) and helium (~10%)
- MoonsMore than 100 confirmed (101 officially recognised as of March 2026)
- Rings4 faint dust rings
- Magnetic fieldStrongest of any planet — about 20,000 × Earth’s
- Named afterThe Roman king of the gods (Greek equivalent: Zeus)
- Visible to the naked eyeYes — often the brightest “star” in the sky
Ask students to use the Quick Facts table to compare Jupiter and Earth across five things: size, gravity, day length, surface, and moons. Which difference surprises them most?
What is Jupiter?
Jupiter is the fifth planet from the Sun and the largest planet in our solar system. Jupiter is a gas giant, made mostly of hydrogen and helium — the same two gases as the Sun. Unlike Earth, Jupiter has no solid surface. It’s giant clouds and gas all the way down.
Jupiter is more than twice the mass of all the other planets in the solar system combined. It weighs as much as 318 Earths. As of 2026, scientists have confirmed more than 100 moons orbiting Jupiter, including four very large ones first spotted by Galileo Galilei in 1610. Jupiter is bright enough to see with the naked eye most nights of the year, and Jupiter was named after the king of the Roman gods.
Where is Jupiter in the solar system?
Counting outwards from the Sun, the order of planets is Mercury, Venus, Earth, Mars, then Jupiter. After Jupiter come Saturn, Uranus and Neptune — but Jupiter is the first of the four gas giants. Between Mars and Jupiter lies the asteroid belt, a huge ring of rocky leftover pieces from when the solar system formed about 4.5 billion years ago. Jupiter is so massive that its gravity helps keep many of those asteroids in their orbits.
Jupiter is about 778 million kilometres (484 million miles) from the Sun — more than five times farther than Earth. Sunlight is much weaker that far out: Jupiter gets only about 1/25th of the sunlight Earth does.
Just how big is Jupiter?
Jupiter is enormous. You could line up 11 Earths side-by-side to stretch all the way across Jupiter, and 1,321 Earths would fit inside Jupiter’s volume — more than thirteen hundred Earths. Jupiter is 318 times more massive than Earth.
Jupiter’s gravity at the cloud tops is about 2.5 times stronger than Earth’s gravity. So a child who weighs 30 kg on Earth would weigh about 75 kg standing at Jupiter’s cloud tops.
Despite its size, Jupiter is still tiny compared to the Sun. About 1,000 Jupiters could fit inside the Sun.
But Jupiter is the most massive object in our solar system besides the Sun — more than twice as massive as all the other seven planets put together. Jupiter’s huge gravity has shaped the orbits of asteroids, comets and moons throughout our solar system’s history.
What is Jupiter made of?
Jupiter is made mostly of hydrogen and helium — the same two gases that make up the Sun. Hydrogen makes up about 90% of Jupiter’s atoms, with helium and small amounts of other gases (methane, ammonia, water vapour) making up the rest.
At the top of Jupiter is a thick layer of clouds. Below the clouds, the atmosphere gets thicker and hotter the deeper you go. Eventually the gas becomes so squashed that it acts more like a liquid than a gas. Even deeper, the pressure is so strong that hydrogen acts like a liquid metal — this strange layer is called metallic hydrogen.
At Jupiter’s very centre is a hot, “fuzzy” core, made of rock and metal all mixed together. The core might be about the size of Earth, but it’s not solid like Earth’s core. NASA’s Juno spacecraft discovered in 2017 that Jupiter’s core is more spread-out and mushy than scientists used to think.
The most important thing to remember? Jupiter has no solid surface anywhere. A spacecraft trying to land on Jupiter would not find any ground. It would simply sink through layers of gas, then liquid, then the strange metallic hydrogen — being crushed by the pressure long before it reached the centre.
Jupiter has a surface you could stand on.
Jupiter is a gas giant — there is no solid ground anywhere. A spacecraft would just sink through layers of gas and liquid.
Jupiter’s three cloud layers
Jupiter has three main layers of clouds, stacked on top of each other:
- Top layer: white ammonia clouds — the highest, coldest, and brightest. This is what makes Jupiter’s brightest bands so white.
- Middle layer: brown clouds made of a chemical called ammonium hydrosulfide. These are what give Jupiter’s darker bands their brown and orange colour.
- Bottom layer: water ice clouds — the deepest cloud layer, where Jupiter’s lightning happens.
If you could bottle a sample of Jupiter’s clouds, the air inside would smell awful. Ammonia smells like strong cleaning products. The brown clouds have sulfur in them, which smells like rotten eggs. The water clouds lower down would be more familiar — but Jupiter is far too cold, stormy, and dangerous for anyone to visit in person.
Inside Jupiter: liquid metal hydrogen
Deep below Jupiter’s clouds, the pressure becomes so huge that hydrogen starts to act in a very strange way. It stops being a gas. It stops even being a normal liquid. Instead, it becomes metallic hydrogen — a kind of liquid metal that can carry electricity, like a copper wire.
This layer of metallic hydrogen is what gives Jupiter its incredible magnetic field, which we’ll come to later. Jupiter’s fast spin stirs the metallic hydrogen, and the moving electric currents make Jupiter the strongest planet-sized magnet in our solar system.
Scientists can’t make metallic hydrogen for very long here on Earth — they need millions of times the pressure of Earth’s air to make it, and even then it only lasts a tiny fraction of a second. Jupiter has a layer of it thousands of kilometres thick.
METALLIC HYDROGEN — hydrogen squeezed so hard it acts like a liquid metal. It can carry electricity, like a copper wire.
Jupiter is mostly hydrogen and helium. It has no solid ground. Deep inside, pressure squeezes hydrogen into a strange liquid metal called metallic hydrogen, which makes Jupiter’s huge magnetic field.
Why does Jupiter have stripes?
Look at any photo of Jupiter and the first thing you’ll notice is the stripes. Jupiter’s stripes are huge bands of clouds, stretched all the way around the planet by its super-fast spin.
The light bands are called zones. In a zone, warm gas is rising from deep inside Jupiter, forming bright ammonia clouds at the top. Zones look creamy white.
The dark bands are called belts. In a belt, cooler gas is sinking back down. The darker, lower cloud layers show through, so belts look brown or orange.
Jupiter has many belts and zones at different latitudes (different heights up and down the planet), with names like the North Equatorial Belt and the Equatorial Zone. The belts and zones can change over time — sometimes a belt will fade away for a year or two and then return.
The jet streams between belts and zones are some of the fastest winds in the solar system. They reach wind speeds of up to 540 kilometres per hour — faster than the strongest hurricane on Earth.
Jupiter spins so fast that its middle bulges outward. Jupiter isn’t a perfect sphere — it’s slightly squashed at the top and bottom. You can see the squash in any clear photo if you look closely.
The Great Red Spot — the biggest storm in the solar system
The Great Red Spot is Jupiter’s most famous feature — a giant storm in Jupiter’s southern half that has been spinning for at least 190 years.
The Great Red Spot is about 16,500 kilometres (10,250 miles) wide — big enough to swallow Earth whole. It’s an oval-shaped storm that spins counter-clockwise, completing one rotation about every six Earth days.
Astronomers have been watching the Great Red Spot continuously since the 1830s, when telescopes first became powerful enough to track it. A different storm at about the same place was sketched by the Italian astronomer Cassini back in the 1660s, but most scientists think that earlier storm faded away before the current one started.
NASA’s Juno spacecraft flew over the Great Red Spot in 2017 and discovered something amazing: the storm is much deeper than scientists thought. It reaches down at least 300 kilometres into Jupiter’s atmosphere — far below the cloud tops we see.
❓ Space Mystery
Nobody is completely sure why the Great Red Spot is red — or why it has lasted so much longer than storms on Earth. The most popular idea is that sunlight breaks chemicals in Jupiter’s clouds into red and orange compounds. Other storms on Jupiter end up different colours, including white, brown and pink.
Read the full story of the Great Red Spot →
Is the Great Red Spot shrinking?
Yes — the Great Red Spot is shrinking. Hubble Space Telescope photos show it has been getting smaller for over 150 years.
In the late 1800s, the Great Red Spot was wide enough to hold three Earths side by side. Today, only one Earth fits across it. Scientists aren’t sure if it will keep shrinking, stop, or even disappear one day.
NASA scientist Amy Simon leads a team that measures the Great Red Spot every year using Hubble. The latest measurement gave a width of about 16,500 kilometres. We update this page each year when new Hubble data comes out.
Then (1879): wide enough for 3 Earths
Now (2024): wide enough for about 1 Earth
Jupiter’s other storms and weather
The Great Red Spot is the most famous, but Jupiter has lots of other amazing storms.
Oval BA (sometimes called “Red Spot Jr.”) is a smaller red storm just below the Great Red Spot. It formed in the year 2000 when three smaller white storms merged together. It turned red in 2006 — nobody is sure exactly why.
Polar cyclones. When NASA’s Juno spacecraft started flying over Jupiter’s poles in 2016, scientists got a huge surprise: giant cyclones were spinning at both poles. Eight cyclones spin around a ninth one at the North Pole. Five cyclones do the same at the South Pole. They’ve stayed stable for years — they don’t merge or break up.
Lightning. Juno also spotted lightning flashing in Jupiter’s clouds. Some of it happens much higher up than scientists expected — in places that should be too cold for water clouds to form.
Wind speeds. The jet streams between Jupiter’s belts and zones reach 540 km/h. That’s faster than the strongest hurricane on Earth — and Jupiter’s storms can last for hundreds of years, because there’s no land or sea to slow them down.
See more on Jupiter’s storms →
Jupiter’s moons — over 100 and counting
As of 2026, Jupiter has more than 100 confirmed moons, according to the International Astronomical Union’s Minor Planet Center. A March 2026 update brought the officially recognised count to 101, and astronomers may confirm more in the future.
Most of Jupiter’s moons are tiny — only a few kilometres across. They orbit far from Jupiter in tilted, stretched-out paths, and many orbit Jupiter backwards. Astronomers think these small moons are asteroids or comet fragments that Jupiter’s enormous gravity captured long ago.
The four biggest moons are the Galilean moons — Io, Europa, Ganymede and Callisto. They were first seen by Galileo Galilei in 1610, and they’re so big you can spot them tonight using basic binoculars.
For a long time, Jupiter had the most moons of any planet in our solar system. But in 2023, Saturn took the lead. As of 2026, Saturn has 285 known moons. Both planets keep adding new moons as our telescopes get better at finding them — it isn’t really a competition.
Jupiter has 4 moons (or 79 moons — the older book number).
Jupiter has more than 100 confirmed moons. The four big ones are the Galilean moons. The other 100+ are much smaller.
Why does Jupiter have so many moons? →
Meet the Galilean moons
Jupiter’s four biggest moons are amazing worlds of their own. Each one is very different from the others.
Io — the closest of the four to Jupiter, and the most volcanically active body in our entire solar system. Hundreds of active volcanoes paint Io’s surface yellow, orange and red with sulfur. Io is covered in lava, has no impact craters left, and erupts so much that volcanic plumes shoot hundreds of kilometres into space. Read more about Io →
Europa — the second moon. Europa has a smooth icy surface hiding a huge ocean of liquid salty water underneath. Scientists think Europa’s ocean holds more water than all of Earth’s oceans combined. NASA’s Europa Clipper spacecraft, scheduled to arrive at Jupiter in April 2030, is going there to investigate. Read more about Europa →
Ganymede — the third moon, and the biggest moon in the solar system. Ganymede is bigger than the planet Mercury! It’s also the only moon known to have its own magnetic field. ESA’s JUICE spacecraft is planned to reach Jupiter in 2031 and to enter orbit around Ganymede in 2034. Read more about Ganymede →
Callisto — the fourth moon, and the most heavily cratered body in the solar system. Callisto’s surface is so covered with impact craters there’s hardly a smooth spot left. It preserves a record of impacts going back 4 billion years. Read more about Callisto →
If you watched Jupiter through a telescope, night after night, you would see its four big moons change places around it — sometimes a line of three, sometimes a line of four, sometimes one moon is hiding behind Jupiter. Galileo watched this same dance in 1610.
Does Jupiter have rings?
Yes — Jupiter does have rings! Jupiter has four faint rings made mostly of dust. NASA’s Voyager 1 spacecraft discovered them in 1979 as it flew past Jupiter, almost by accident.
Jupiter’s rings are very different from Saturn’s bright icy rings. Jupiter’s rings are dark, narrow, and made of tiny particles that scatter sunlight rather than reflect it. That’s why they’re so much harder to spot from Earth.
From innermost to outermost, Jupiter’s four rings are:
- Halo Ring — the closest to Jupiter, and the faintest
- Main Ring — the brightest of Jupiter’s rings, though still much fainter than Saturn’s
- Two Gossamer Rings — even fainter, made of dust shed by small inner moons
The Main Ring is “shepherded” by two tiny moons, Adrastea and Metis, whose gravity keeps the ring particles in line. The Gossamer Rings are fed by dust that’s knocked off the slightly larger inner moons Amalthea and Thebe whenever small meteoroids strike them.
Voyager 1 didn’t expect to find rings around Jupiter at all. The team only got the photo because one scientist wanted to test the camera. Sometimes the biggest discoveries happen by accident!
Read more about Jupiter’s rings →
Jupiter’s magnetic field and auroras
Jupiter has the strongest magnetic field of any planet in our solar system — about 20,000 times stronger than Earth’s. The magnetic field is made deep inside Jupiter, where the layer of liquid metallic hydrogen carries electricity. Jupiter’s super-fast spin stirs that flow into a planet-wide electromagnet.
Jupiter’s magnetic field reaches far out into space, forming an invisible region called the magnetosphere. Jupiter’s magnetosphere is so big that its tail stretches all the way past Saturn’s orbit.
The magnetic field also creates the most powerful auroras in the solar system. Auroras are glowing lights that happen when fast-moving particles from space slam into a planet’s atmosphere near the poles. Earth has auroras too — the Northern Lights and Southern Lights. But Jupiter’s auroras are far stronger, and they glow brightest in ultraviolet light (a kind of light human eyes can’t see).
The James Webb Space Telescope and the Hubble Space Telescope have both taken stunning photos of Jupiter’s auroras. Some of the particles that power them come all the way from Io’s volcanoes, carried through Jupiter’s magnetic field by a doughnut-shaped cloud called the Io plasma torus.
Jupiter’s magnetic field traps so much radiation that spacecraft visiting Jupiter need special protection. NASA’s Juno spacecraft kept its electronics inside a heavy titanium box — like a tiny safe — to shield them from the radiation.
Read more about Jupiter’s magnetic field →
How did Jupiter form?
Jupiter formed about 4.5 billion years ago, when our solar system was just a swirling cloud of gas and dust around the young Sun. Scientists think Jupiter was probably the first planet to form — before Earth, before all the rocky planets.
Being first, Jupiter grabbed most of the leftover material that didn’t go into the Sun. That’s why Jupiter ended up so massive: more than twice the mass of all the other planets put together.
Because Jupiter formed first and grew so big, it shaped the rest of the solar system. Jupiter’s huge gravity:
- Helped form the asteroid belt by stopping a small planet from ever coming together between Mars and Jupiter
- Scattered some early planet-sized bodies right out of the solar system
- May have delivered water to the inner planets like Earth, by sending icy comets inwards
Jupiter is sometimes called a “failed star” because it’s made of the same hydrogen and helium gas as the Sun. But Jupiter is much, much smaller than the smallest possible star. To start the nuclear reactions that make stars shine, Jupiter would need to be about 80 times more massive.
Jupiter could become a star one day.
Jupiter would need to grow about 80 times heavier to start nuclear fusion in its core. There’s no way for that to happen naturally — Jupiter will stay a planet forever.
Read more about how Jupiter formed →
Jupiter vs Earth — how different are they?
Jupiter is a gas giant. Earth is a rocky planet. They could not be more different.
| Jupiter | Earth | |
|---|---|---|
| Width across | 11 × Earth’s | 1 × Earth’s |
| Mass | 318 × Earth’s | 1 × Earth’s |
| Day length | 9 hours 56 minutes | 24 hours |
| Year length | 11.86 Earth years | 365.25 days |
| Gravity | About 2.5 × Earth’s | 1 × Earth’s |
| Atmosphere | Mostly hydrogen + helium | Mostly nitrogen + oxygen |
| Surface | No solid surface | Solid land and water |
| Moons | More than 100 | 1 (the Moon) |
| Rings | 4 faint dust rings | None |
| Magnetic field | About 20,000 × Earth’s | Standard |
| Average temperature | About −145°C (cloud tops) | About 15°C (surface) |
The biggest difference of all? Earth has everything we need to live: oxygen we can breathe, liquid water, land to walk on, plants, animals, and a comfortable temperature. Jupiter has none of those things. Jupiter is fascinating to study — but Earth is the only place we know of in the whole universe where life exists.
Read more about Jupiter vs Earth →
How have we explored Jupiter?
No human has ever travelled to Jupiter — the journey is too long, the radiation too dangerous, and there’s no place to land. But over the past 50 years, nine robotic spacecraft have flown past, orbited, or studied Jupiter up close. Each one has helped us learn something new.
Here are all the spacecraft that have visited Jupiter so far:
- Pioneer 10 (1973) — the first spacecraft ever to reach Jupiter
- Pioneer 11 (1974) — flew past Jupiter on the way to Saturn
- Voyager 1 (1979) — discovered Jupiter’s rings and Io’s volcanoes
- Voyager 2 (1979) — close-up photos of all four Galilean moons
- Ulysses (1992) — used Jupiter’s gravity to fly over the Sun’s poles
- Galileo orbiter (1995–2003) — first to orbit Jupiter; dropped a probe into the clouds
- Cassini (2000) — flew past Jupiter on the way to Saturn
- New Horizons (2007) — flew past Jupiter on the way to Pluto
- Juno (2016–2025) — studied Jupiter’s poles, deep storms, and fuzzy core
And two more spacecraft are on their way right now: NASA’s Europa Clipper and ESA’s JUICE. You’ll meet them in a moment.
Read more about the first missions to Jupiter →
NASA’s Juno mission (2016–2025)
NASA’s Juno spacecraft arrived at Jupiter on 4 July 2016. Juno was built to fly closer to Jupiter than any spacecraft before — looking deep below the cloud tops to study Jupiter’s interior, magnetic field, and weather.
Juno made discoveries that changed what scientists know about Jupiter:
- The groups of polar cyclones spinning at both poles
- Lightning happening much higher in the clouds than anyone expected
- The fuzzy, mushy core stretching out into Jupiter’s middle
- The first close-up photos of Io and Europa in over twenty years
Juno’s mission was extended several times. The last extension was funded through September 2025, and Juno’s current status is uncertain. Even if the spacecraft itself has finished, the discoveries it made will keep teaching us about Jupiter for decades.
On 4 July 2016 — American Independence Day — Juno fired its engine to slow down and slip into orbit around Jupiter. The mission team held their breath for 35 minutes while Juno did the manoeuvre on its own, then waited for the spacecraft to phone home: success.
Read more about NASA’s Juno mission →
Europa Clipper — searching for life under the ice
NASA’s Europa Clipper spacecraft launched on 14 October 2024 to study Jupiter’s icy moon Europa. Europa Clipper is the largest planetary spacecraft NASA has ever built.
To save fuel, Europa Clipper is taking a long path through the solar system with two gravity-assist flybys:
- February 2025 — Mars flyby (already happened)
- December 2026 — Earth flyby (coming up)
- April 2030 — scheduled to arrive at Jupiter
Once it arrives, Europa Clipper is scheduled to fly past Europa 49 times, studying the hidden ocean, the ice shell, and the surface chemistry. The mission isn’t searching directly for aliens — it’s checking whether Europa has the right ingredients to support tiny life like the deep-ocean bacteria we have on Earth.
A poem by U.S. Poet Laureate Ada Limón, called “In Praise of Mystery,” is engraved on the Europa Clipper spacecraft — along with the names of more than 2.6 million people who signed up online.
Read more about Europa Clipper →
JUICE — Europe’s mission to Jupiter’s icy moons
The Jupiter Icy Moons Explorer, or JUICE, is the European Space Agency’s big mission to Jupiter. JUICE launched on 14 April 2023 and is planned to reach Jupiter in July 2031.
To get there, JUICE is taking a winding path with several gravity-assist flybys:
- August 2024 — Moon-then-Earth flyby (a world first)
- August 2025 — Venus flyby
- September 2026 — Earth flyby (coming up)
- January 2029 — final Earth flyby
- July 2031 — planned arrival at Jupiter
Once at Jupiter, JUICE is planned to fly past Europa and Callisto, and then in December 2034 it is planned to enter orbit around Ganymede — becoming the first spacecraft ever to orbit a moon of another planet.
JUICE made a world-first manoeuvre in August 2024 — flying past the Moon, and then past Earth, within a single day. No spacecraft had ever done that before. Picking up speed from both the Moon and Earth saved JUICE about a year of cruising time.
When a comet crashed into Jupiter (1994)
In 1992, a comet called Shoemaker-Levy 9 wandered too close to Jupiter. Jupiter’s enormous gravity tore the comet into 21 separate pieces, leaving them strung out in a long line.
Astronomers Carolyn Shoemaker, Eugene Shoemaker and David Levy spotted the broken comet in 1993, and quickly realised it was heading straight for Jupiter. Between 16 and 22 July 1994, all 21 pieces crashed into Jupiter, one after another, leaving dark scars in Jupiter’s clouds that were each bigger than Earth.
It was the first time humans had ever watched a planetary collision happen live. Telescopes around the world — and the Hubble Space Telescope above them — pointed at Jupiter the whole week to record every impact. Scientists learned a huge amount about Jupiter’s atmosphere by watching how the impact debris spread, mixed, and slowly faded over the following months.
Read more about Shoemaker-Levy 9 →
How did Jupiter get its name?
Jupiter is named after the Roman king of the gods. The Latin name Iuppiter means something like “sky father”, and the Romans gave the name to the brightest wandering star they could see — the king of the night sky, named after the king of the gods.
But the Romans weren’t the first to spot Jupiter, or to give it a name. Jupiter is one of the few planets bright enough to see without a telescope, so almost every ancient culture noticed it and gave it a name of their own.
- Greek: Zeus — king of the Greek gods (the same character as Jupiter)
- Babylonian (over 3,000 years ago): Marduk — king of the Babylonian gods
- Hindu: Brihaspati — teacher of the gods, also called Guru
- Chinese: 木星 (Mùxīng), or “Wood Star” — Jupiter is the planet of the wood element in traditional Chinese astronomy
- Norse: Some old stories link Jupiter to Thor, the thunder god
Most of the moons of Jupiter are also named after characters from Greek mythology connected to Zeus — Io, Europa, Ganymede and Callisto were all important figures in Zeus’s stories.
The Hindu name for Jupiter — Brihaspati — has been used for more than 3,000 years, and it’s also the source of the Hindi word for Thursday (Brihaspativar). Many other languages name Thursday after Jupiter or Thor, including French (jeudi), Italian (giovedì), and old English (Thor’s day → Thursday).
Read more about Jupiter’s name and mythology →
How to see Jupiter for yourself
You don’t need any special equipment to see Jupiter. It’s one of the brightest things in the night sky — often the second-brightest object after the Moon (and sometimes after Venus).
Jupiter looks like a very bright “star” that doesn’t twinkle the way real stars do. That’s how astronomers tell planets and stars apart — stars twinkle, planets shine steadily.
The best time to spot Jupiter is during a period called opposition, when Earth passes between Jupiter and the Sun, and Jupiter is at its brightest and closest. Opposition happens about every 13 months.
To find Jupiter tonight:
- Use a free sky-map app like Stellarium or SkySafari
- Open the app at the time it suggests — usually after sunset
- Find the brightest “star” the app points to — that’s Jupiter
What you’ll see depends on what you look through:
- Naked eye: a bright, steady, golden “star”
- Binoculars: a small disc and up to four tiny dots beside it — those are the Galilean moons!
- A small telescope: stripes across Jupiter, and the Great Red Spot if it’s facing your way
Sketch what you see each night for a week. You’ll notice the Galilean moons change places night after night — exactly as Galileo did in 1610. Some nights you’ll see a line of four, some nights only three, because one moon is hiding behind Jupiter.
Pair this section with the printable Jupiter Sky Journal — a 4-week observation worksheet that turns finding Jupiter into a class project (download link at the bottom of the page).
Read more about how to see Jupiter →
Curious questions about Jupiter
Jupiter is a planet that breaks all the normal planet rules — so it’s no surprise that kids (and scientists) ask some pretty wild questions about it. Here are three of our favourites.
What would happen if you fell into Jupiter?
You couldn’t — Jupiter is far too far away from Earth, and there’s no way to get close to it without a spacecraft. Even spacecraft don’t go anywhere near the inside of Jupiter.
But if a spacecraft did try, the journey would be short. The top of the atmosphere would feel like flying through wind. A few hundred kilometres down, the gas would be as thick as water. Deeper still, the pressure would crush even the strongest spacecraft. NASA’s Galileo probe — the only object ever to fall on purpose into Jupiter’s atmosphere — only lasted 57 minutes before the pressure broke it.
Can it rain diamonds on Jupiter?
Maybe! Some scientists think lightning storms inside Jupiter can turn carbon from methane gas into solid carbon — and if the pressure squeezes it hard enough, the solid carbon could become tiny diamonds. The diamonds might then sink deeper into Jupiter, slowly melting into a kind of diamond rain.
Other scientists aren’t sure this really happens. We won’t know for certain until a future spacecraft can study Jupiter’s deep atmosphere up close.
Why is Jupiter so colourful?
The cream and orange stripes you see on Jupiter come from chemicals in its clouds. White ammonia clouds make the brightest bands; brown and orange chemicals deeper down show through wherever the ammonia is thinner. Sulfur and phosphorus in the clouds may help create the red, orange and brown shades.
Scientists are still working out exactly which chemicals make each colour. It’s one of Jupiter’s many ongoing mysteries — one that NASA’s Juno mission helped uncover, and that future missions will study further.
Read more curious Jupiter questions →
Frequently asked questions about Jupiter
Why is Jupiter called the “king of the planets”?
Jupiter earned that nickname because it’s the biggest, brightest, and most powerful planet in our solar system. It’s also named after the king of the Roman gods. Jupiter has more mass than all the other planets combined, more than 100 moons, and the strongest magnetic field of any planet.
How big is Jupiter compared to Earth?
Jupiter is enormous — about 11 times wider than Earth, with 318 times Earth’s mass. You could fit 1,321 Earths inside Jupiter’s volume. Despite that size, Jupiter is still much smaller than the Sun: about 1,000 Jupiters could fit inside the Sun.
How long is a day on Jupiter?
A day on Jupiter is only 9 hours and 56 minutes long — the shortest day of any planet in our solar system. Jupiter spins so fast that its middle bulges outwards.
How long is a year on Jupiter?
A year on Jupiter is 11.86 Earth years. That’s how long Jupiter takes to go all the way around the Sun. If you’re 12 years old, you wouldn’t even be 1 year old on Jupiter.
Is Jupiter bigger than the Sun?
No. Jupiter is the biggest planet — but the Sun is much, much bigger. About 1,000 Jupiters could fit inside the Sun. The Sun also has about 1,000 times more mass than Jupiter.
Can you stand on Jupiter?
No — Jupiter has no solid surface anywhere. It’s a gas giant, with clouds at the top, then gas that turns to liquid, then liquid metallic hydrogen, all the way down to a fuzzy core. A spacecraft trying to “land” would just sink and be crushed by the pressure.
What is Jupiter made of?
Jupiter is made mostly of two gases: hydrogen (about 90% of its atoms) and helium (about 10%), with small amounts of methane, ammonia and water vapour. These are the same gases that make up the Sun.
Is Jupiter a star?
No, Jupiter is a planet. It’s made of similar gases to the Sun, but it would need to be about 80 times more massive to start the nuclear reactions that make stars shine. Jupiter will be a planet forever.
What’s deep inside Jupiter?
Below Jupiter’s clouds, the gas gets thicker until it becomes a liquid. Even deeper, the pressure squeezes hydrogen into metallic hydrogen — a kind of liquid metal that can carry electricity. At Jupiter’s centre is a hot, fuzzy core made of rock and metal mixed together.
How big is the Great Red Spot?
The Great Red Spot is about 16,500 kilometres (10,250 miles) wide — big enough to swallow Earth. It used to be much bigger; in the late 1800s, three Earths could fit across it side-by-side. Today, only one Earth fits.
How long has the Great Red Spot been there?
Astronomers have been watching the Great Red Spot continuously since the 1830s — at least 190 years. A different storm at about the same place was sketched in the 1660s, but most scientists think that earlier storm faded away before the current one started.
Why is the Great Red Spot red?
Nobody is completely sure. The most popular idea is that sunlight breaks chemicals in Jupiter’s clouds into red and orange compounds. Other storms on Jupiter end up different colours — white, brown and even pink — so the recipe for “red” must be quite special.
How many moons does Jupiter have?
Jupiter has more than 100 confirmed moons. A March 2026 update brought the officially recognised count to 101, and astronomers may confirm more in the future. Saturn currently has more known moons — 285 — but both planets keep adding new ones as telescopes get better.
What are the names of Jupiter’s biggest moons?
Jupiter’s four biggest moons are Io, Europa, Ganymede and Callisto — together they’re called the Galilean moons. The Italian astronomer Galileo Galilei first spotted them through his telescope in 1610.
Could there be life on one of Jupiter’s moons?
Maybe. Europa has a huge ocean of liquid salty water hidden under its ice — possibly more water than all of Earth’s oceans combined. NASA’s Europa Clipper spacecraft is going there to check whether Europa has the right conditions for tiny life like Earth’s deep-ocean bacteria. It isn’t searching for aliens like the ones in movies.
Which is the biggest moon of Jupiter?
Ganymede is the biggest — and it’s also the biggest moon in the whole solar system. Ganymede is bigger than the planet Mercury, and it’s the only moon known to have its own magnetic field.
Does Jupiter have rings?
Yes! Jupiter has four faint rings made mostly of dust. NASA’s Voyager 1 spacecraft discovered them in 1979 — almost by accident. Jupiter’s rings are much darker and harder to see than Saturn’s bright, icy rings.
Could humans ever live on Jupiter?
No. Jupiter has no solid surface to stand on, no breathable air, and dangerous radiation. People will never live on Jupiter. Some scientists think Europa, one of Jupiter’s moons, could be a more realistic future destination — but Jupiter itself is a “look but don’t touch” world.
What spacecraft have visited Jupiter?
Nine spacecraft so far: Pioneer 10 and 11, Voyager 1 and 2, Ulysses, the Galileo orbiter, Cassini, New Horizons, and Juno. Two more are on the way right now — NASA’s Europa Clipper (arriving 2030) and ESA’s JUICE (arriving 2031).
Can I see Jupiter from Earth?
Yes — Jupiter is one of the brightest things in the night sky. You don’t need a telescope. Use a sky-map app like Stellarium or SkySafari to find it after sunset. With basic binoculars, you can even spot Jupiter’s four big Galilean moons.
Quick recap
- Jupiter is the biggest planet in our solar system — 11 Earths could line up across it
- Jupiter is a gas giant — no solid surface, made mostly of hydrogen and helium
- The Great Red Spot is a storm wider than Earth that has lasted at least 190 years
- Jupiter has more than 100 moons, with four big ones (Io, Europa, Ganymede, Callisto)
- Jupiter has 4 faint dust rings and the strongest magnetic field of any planet
- Nine spacecraft have visited Jupiter; two more (Europa Clipper, JUICE) are on the way
- Jupiter is bright enough to see tonight without a telescope
Now choose a topic above to explore further — or look up at the sky tonight and find Jupiter for yourself.
