The gas giant Jupiter is the 5th furthest planet from the Sun and the largest planet in our solar system. In fact if you took all of the other planets from our solar system and added their mass together, Jupiter would still be two and a half times larger.

Jupiter is known as a gas giant because it is made up gases, primarily hydrogen.

It does not have a solid surface because of the gaseous nature of the planet, but it likely has a rocky core.

It has a very distinctive colouration, with brightly coloured bands of cloud which contain different weather systems and it also has a famous Great Red Spot which is in fact a massive hurricane that is around three times as wide as the Earth and has been blowing for several hundred years.

Jupiter, a composite of 4 images taken by the Cassini spacecraft Jupiter and its four moons from Voyager 1(not to scale but in position) Gallileo captures Jupiter's Great Red Spot
Click an image above to view full size image. Hover over for description.

Jupiter’s moons

Jupiter is known to have 67 different moons, although this figure often changes as new moons are discovered over time. The majority of the moons are small – less than 7 miles in diameter, but there are eight moons that are considered large with the four “Galilean” moons being the most famous after being first discovered by the Italian astronomer Galileo Galilei in 1610.

Moving from the closest moon to Jupiter to the furthest away, the four Galilean moons are called Io, Europa, Ganymede, and Calisto. To put the size of these objects into scale, the largest of the moons Ganymede, is similar in size to the planet Mercury.

There are a number of objects that are technically Jupiter’s moons that lie in orbit at outer regions and these 30 or so moons orbit in the opposite direction. It is believed that these moons were originally asteroids, but due to the size of Jupiter and the strength of its magnetic field, any large object near to Jupiter is either sucked towards it and destroyed or pulled into orbit. The outer moons were object large enough not to be destroyed so they were pulled into orbit.

Jupiter Facts

The first recorded details of the planet Jupiter were by the ancient Babylonians in around the 8th century BC, the Greeks later termed the planet after their god of thunder Zeus and latterly the Romans named the planet Jupiter after the Roman God Jupiter (Sometimes called Jove) who was referred to as the king of the gods.

Jupiter is a bright planet that can be viewed by the naked eye in the night sky and very occasionally it can be viewed in the daytime when the Sun is low.

The planet Jupiter is the fourth brightest object in the sky after (in order) the Sun, Moon, and Venus.

Jupiter is the fifth furthest planet from the Sun and averages a distance of 779 million kilometres from the Sun.

The largest planet in the solar system, Jupiter has a diameter of 142,983 kilometres which is just over 11 times the diameter of the Earth. This means incredibly you could fit around 1,300 planet Earth’s inside Jupiter.

Only recently have we discovered the existence of planetary rings around Jupiter. There are three separate faint rings which are termed as the halo, main ring and gossamer ring. Scientists believe that the rings are made out of dust, rather than made out of ice as is the case with the pronounced rings of Saturn.

Jupiter completes a full orbit every 11.86 years.

Jupiter has the shortest day of all the planets in our solar system. It completes a full rotation on its axis once every 9 hours and 55 minutes. The fact that the planet rotates so quickly means Jupiter is subject to fierce weather systems that can stop and start very quickly.

The atmosphere of Jupiter is mainly made up of hydrogen (75%), helium (24%), and trace elements of ammonia, carbon, methane, neon, oxygen, sulphur and water vapour. The planet core is predicted to be dense, solid and around the same size as the Earth.

There have been eight spacecraft that have visited Jupiter. These are the Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Galileo, Cassini, Ulysses and New Horizons. There is a craft on its way to Jupiter (Juno mission) which is planned to arrive in the year 2016.

Jupiter does not have the type of environment to sustain life as we know it, but it is thought that some of Jupiter’s moons may have oceans under their crusts so there could be the potential to sustain some form of life.

Figures and Statistics

  Jupiter Earth Ratio (Planet to Earth)
Rotation period - (hours) 9.9250 23.9345 0.415
Length of day - (hours) 9.9259 24.00 0.414
Length of year (earth days) 4329.63 365 11.862
One complete orbit takes (earth days) 4332.589 365.256 11.862
Radius (km) 71492 6378.1 11.209
Mass (1024 kg) 1898.3 5.9726 317.83
Volume (1010 km3) 143128 108.321 1321.33
Density (kg/m3) 1326 5514 0.240
Distance from Earth - Min (106km) 588.5 - -
Distance from Earth - Max - (106km) 968.1 - -
Average distance from Sun (106km) 778.57 149.6 5.204
Orbital radius (106km) 740 - 817 147 - 152 5.034 - 5.369
Orbital velocity (average - km/s) 13.06 29.78 0.439
Rotational velocity (km/h) 45300 1674.4 27.054
Surface gravity (m/s2) 24.79 9.81 2.527
Surface temp - Average (K) 165 184 0.897
Axial tilt (degrees) 3.13 23.44 0.134
Number of natural satellites (moons) 67 1 67