In July 1994, the fragments of Comet Shoemaker-Levy collided with Jupiter, producing the largest explosions ever observed in our solar system. The fragments left behind dark patches in the clouds of Jupiter, allowing astronomers to observe the way Jupiter’s atmosphere works.

Jupiter rotates on its axis every 9 hours and 55 minutes.

In December 1995, the Galileo spacecraft went into orbit around Jupiter and began returning close-up images of Jupiter’s atmosphere and moons.

The basics

Order (outwards from the Sun): 5
Average distance from the Sun: 778 300 000 km (5.20 astronomical units)
Period of revolution (length of year): 11.86 years
Period of rotation (length of day): 9 hours 55 minutes at the equator
Diameter: 142 980 km at the equator
Surface gravity: 2.54 times greater than Earth’s
Composition: Scientists do not agree on whether Jupiter has a solid rocky core or if it consists only of gases that condense in the middle to form liquids. The interior ocean is made primarily of hydrogen and helium, with a few other gases
Atmosphere: Hydrogen, helium, some methane and ammonia
Satellites: 61 moons and one faint ring
Surface temperature: 10 000 degrees Celsius in the interior ocean; -140 degrees Celsius at the cloud tops; 25 000 degrees Celsius at the centre. Therefore, Jupiter radiates more heat than it receives

Appearance of surface

The visible cloud tops of Jupiter are divided into multicoloured cloud belts and zones, stretched out by Jupiter’s rapid rotation. The Great Red Spot, easily visible with small telescopes, is the largest example of the many violent storms in Jupiter’s atmosphere. There is a vast liquid hydrogen ocean under the visible cloud tops.

Appearance in Earth’s sky

Jupiter is easily visible for about 10 months of the year, appearing as a very bright, star-like object.

Telescopic appearance

Jupiter offers a wealth of detail to telescope users. The cloud bands, the Great Red Spot, and the four Galilean moons are all easily visible.


Canadian Heritage Information Network
Australian Museums & Galleries Online, Australia; Centre of the Universe; Gemini Observatory, Hawaii; Glenbow Museum; The Manitoba Museum; National Research Council Canada; Planétarium de Montréal

© Canadian Heritage Information Network, 2003

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