Jupiter Facts

Jupiter is the fifth and the biggest planet in the solar system. It is two and a half times bigger than all the other planets combined and is also the oldest planet. It is aptly named after Roman king of Gods.

Jupiter Profile

Interesting Jupiter Facts

  • Jupiter is the fifth planet in the solar system.
  • It is the largest planet in the solar system.
  • Jupiter is named after the Roman king of Gods.
  • It is one of the two gas giants along with Saturn.
  • It is the third brightest object in the night sky after the moon and Venus.
  • It takes 11.9 years to revolve around the sun.
  • Jupiter is known to have 79 moons.
  • Jupiter is known to have rings.
  • The mass of Jupiter is more than two and a half times the mass of all the other planets in the solar system combined.
  • The mass of Jupiter is one-thousandth the mass of the sun. 
  • The Great Red Spot on Jupiter is a storm that has been going on the planet for over 450 years.
  • Jupiter has the shortest day of all the other planets, despite its largest size.
  • Until today, nine spacecrafts have visited Jupiter.
  • 1300 Earths can fit inside Jupiter.
  • Jupiter has the strongest gravity out of all the other planets.


Jupiter has been named after the Roman king of Gods because of its massive size. It is not known when exactly Jupiter was discovered. In the Babylonian texts, Jupiter was called Marduk and in Greek manuscripts, it was called Zeus, the Greek king of Gods.

Since pre-historic times, Jupiter has been known as the ‘wandering star’. In 1610, Galileo Galilei observed 4 moons orbiting Jupiter with his telescope. He named these moons Io, Europa, Ganymede, and Calisto. These moons were the first celestial bodies to be discovered that revolved around another celestial body, other than the Earth’s moon.

The discovery of these moons was very important as it proved that the Earth is not the center of the universe. It supported Copernicus’ theory of the heliocentric model. Another moon, Amalthea was discovered in 1892. Over the course of time, more moons were discovered. Today, Jupiter is known to have at least 79 moons. 


Jupiter basically has a striped pattern of white, brown and orange. These are nothing but clouds of different colors. Some of these clouds also have eddy shapes, brown and white ovals, and brown barges as well. There are three layers of clouds that keep moving. These layers of clouds are mostly composed of ammonia and sulphur.

One of the most remarkable features of the planet’s appearance is the Great Red Spot. It is a high-pressure region in the atmosphere of Jupiter which is at 23° south of the planet. It has been observed continuously since 1830 i.e. 188 years. It is a huge cyclone or hurricane that has been going on for more than 450 years.

The credit of its first observation often goes to Robert Hooke who observed it in 1664. However, Giovanni Cassini’s observation about the red spot in 1665 was much more convincing. The spot rotates in an anti-clockwise direction about every six days on Earth.

The width of the spot is close to 16,400 kilometers which is much more than the width of the Earth. The reason behind the reddish appearance of the spot is not clear. However, scientists believe that it could be because of the presence of red phosphorus, a sulphur compound or a complex organic molecule. The cause of the storm is still not known. Planet Jupiter has rings.


Jupiter is the largest planet in the solar system. Its mass is about two and a half times the mass of all the other planets in the solar system combined. It is about 1000th the mass of the sun. Had it been 80 times larger, Jupiter would have been a star instead of a planet. It is 779 million kilometers away from the sun.

The equatorial radius of the planet is 71,492 km while its mean radius is 69,911 km. It has a surface area of 61.4 billion kilometers squared.


Jupiter is a gas giant. Hence, it does not have a definite surface. It mostly consists of swirling gases and liquids. This is the reason why a spacecraft cannot properly land on the surface. At the same time, the high pressure and temperatures of the planet do not let spacecrafts fly through either. 


The planet is mostly composed of hydrogen. Nearly 25% of its mass is made up of helium. It also contains traces of ammonia, methane, Sulphur, silicon, ethane, carbon, oxygen and phosphine. Unlike terrestrial planets, it lacks a well-defined structure. It may, however, have a core composed of heavy elements.

Magnetic field & Gravitational Forces

Jupiter has an extremely powerful magnetic field. The magnetic field of Jupiter is 54 times larger than that of the Earth. The magnetic field is created because of the great speed of rotation that Jupiter has.

Also, Jupiter has a tremendous amount of liquid hydrogen. This is also an important contributing factor towards Jupiter’s strong magnetic field.

Orbit & Rotation

Jupiter takes about 11.9 years to revolve around the sun and it takes less than 10 hours, precisely 9 hours and 56 minutes to rotate about its own axis.

This means that Jupiter rotates two and a half times faster than the Earth. Jupiter is known to have a set of rings. The system of rings is referred to as ‘the rings of Jupiter’ or sometimes the ‘Jovian ring system’.

Following Saturn and Uranus, Jupiter was the third planet whose ring system was discovered. The temperature on Jupiter is -145°C. However, inside its core, Jupiter’s temperature can go as high as 24,000°C. This temperature is even hotter than the surface of the sun.


The atmosphere of planet Jupiter is similar to that of the sun. It is the largest atmosphere in the solar system for a planet. It is mostly made up of hydrogen and helium. Other chemicals such as methane, hydrogen sulphide, ammonia, and water are present in very small quantities.

There is no clear lower boundary line for the atmosphere of Jupiter. As we go down towards the surface, the temperature and pressure go on increasing. At one point, the gaseous hydrogen becomes liquid and can sometimes also become solid.

There are four layers in the atmosphere. They are troposphere, stratosphere, thermosphere, and exosphere.


The first layer i.e. the troposphere extends for as long as 50 km. above the surface. The troposphere which is the lower layer is quite complicated. It is a system of hazes and clouds. These hazes and clouds further have layers of ammonia, water, and ammonium hydrosulphide.


The stratosphere i.e. the second layers goes on for almost 320 km above the surface. Here, the temperature increases with height.


The next layer, the thermosphere stretches further for 1000 km. It has no definite end.


The next layer is the exosphere where particles of gas escape into space. 


Jupiter is known to have 79 known moons. Out of these 59, only 53 have been named. The four largest moons are Io, Europa, Ganymede, and Calisto. These four moons are also called Galilean satellites.

The moon Io has the most active volcano in the solar system. The surface of Io is covered in sulphur. Its orbit is almost elliptical in shape. Ganymede is the largest of all moons in the solar system. It is even larger than Mercury, which is a planet.

In fact, it is the ninth-largest celestial body in the solar system. It is also the only moon in the solar system believed to have its own internal magnetic field. It is believed that Europa might have liquid water on its surface.

However, only ice caps have been found on it. Scientists believe that the total water on the surface of Europa could be twice as much as that on the surface of the Earth. It is also believed that Europa could sustain life. 

All four Galilean moons are more than 3100 km in diameter. All the other moons are less than 250 km in diameter, most of them being irregular in shape. All the moons have different directions of spinning and different orbital periods ranging from 7 hours to 3 Earth years. 

Rings of Jupiter

Jupiter has a system of rings known as the ‘Jovian ring system’. It was discovered after the ring systems of Saturn and Uranus. The Voyager 1 space probe was the first spacecraft to observe the rings of Jupiter in 1979.

These rings were further investigated by the Galileo Orbiter in the 1990s. This ring system is very faint and mostly comprises of dust. It has four main components i.e. the halo ring, the main ring, and two gossamer rings. The main ring and the halo ring mostly consist of dust. This dust has been ejected by the two moons Metis, Adrastea and some other bodies.

The gossamer rings are very faint. In infrared light, the halo ring is blue or neutral in colour and the rest of the rings have a reddish appearance. The total mass of the ring system is estimated to be in the range of 10^11 to 10^16 kg. It is not known if the rings were formed with Jupiter or not. However, there is a possibility.


The first observations of Jupiter were recorded by Galileo Galilei in 1610. In the present, Jupiter has been visited by several spacecrafts, probes, and orbiters. The first spacecrafts to fly around Jupiter were Pioneer 10 and 11 and Voyager 1.

They flew by Jupiter in the 1970s. Since then, Galileo has been sent to orbit around Jupiter and also to drop a probe in the atmosphere of the planet. The only spacecraft that is currently orbiting Jupiter is NASA’s Juno. It arrived in the Jovian system in 2016.

Image courtesy: https://www.jpl.nasa.gov/

Potential for Life in Jupiter

No evidence of life has yet been found on the planet Jupiter. The Jovian atmosphere is widely believed to be inhospitable and the possibility of life here is slim. Since Jupiter does not have a proper surface, this makes it a very extreme condition for earth-like life existing on the planet. However, life can exist on Jupiter’s moon Europa as water has been found on its surface. 

Jupiter in Pop Culture

As the solar system’s largest planet, Jupiter has found a place in the Earth’s pop culture as well which includes several films and TV shows some of which are Jupiter Ascending, Cloud Atlas, Futurama, Power Rangers, Halo and has been mentioned in movies like Men in Black.

Some books that revolve around Jupiter or have significantly mentioned Jupiter are Hector Servadac by Jules Verne, The Hideous Strength by C.S. Lewis, the Lensman series by E.E. Smith, A World Out of Time by Larry Niven, Behold a Pale Horse by Milton William Cooper, etc.


  1. 1610: Galileo observes Jupiter in detail for the first time.
  2. 1973: Pioneer 10 fly’s by Jupiter and becomes the first spacecraft to do so while becoming the first spacecraft to cross the asteroid belt at the same time.
  3. 1979: Jupiter’s faint rings are observed for the first time by Voyager 1 and Voyager 2. 
  4. 1979: Voyager 1 and Voyager 2 discover several volcanic activities taking place on the surface of Jupiter’s moon, Io.
  5. 1992: Ulysses swings by Jupiter on 8 February 1992. 
  6. 1994: Scientists observe a comet colliding with the southern part of Jupiter. The comet was believed to be Shoemaker-Levy 9.
  7. 1995: A spacecraft called Galileo drops a probe into the atmosphere of planet Jupiter becoming the first spacecraft to do so. This helps in observing the rings and moons of Jupiter in detail. This mission went on until 2003.
  8. 2000: Spacecraft Cassini reaches the closest to Jupiter than any spacecraft yet at a distance of 10 million kilometers giving a highly detailed photo of the planet.
  9. 2007: NASA’s New Horizons spacecraft on way to Pluto takes photos of Jupiter’s storms and the moons Io and Europa for detailed observations.
  10. 2009: A comet crashes into Jupiter’s southern hemisphere for the first time in 15 years since Shoemaker-Levy 9.
  11. 2011: NASA’s Juno is launched to observe Jupiter’s atmosphere, magnetosphere, chemistry, and internal structure.
  12. 2016: NASA’s Juno reaches Jupiter and conducts a detailed investigation of the planet.


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