Glossary term: Jupiter

Description: Jupiter is the largest planet in the Solar System and the fifth major planet from the Sun. It is a gas giant with a radius of 71,300 kilometers (km), about 11 times the radius of the Earth. The mass of Jupiter (318 times the mass of the Earth) is greater than all the other planets and the smaller bodies in the Solar System put together.

Its typical distance from the Sun is 778 million km, about five astronomical units (Earth–Sun distances), taking a little under 12 years to complete one orbit. As of 2023, astronomers have detected more than 90 moons or natural satellites orbiting Jupiter.

It is visible with the naked eye. Its name in English derives from the Roman king of the gods. Observed in a small telescope we can see cloud belts of different colors and a giant red circular storm region (the so-called Great Red Spot). A few space probes have been sent to Jupiter over the past decades, and in 2016 the NASA spacecraft Juno started exploring Jupiter and its moons in much greater detail.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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The planet Jupiter with the two of the four Galilean moons (visible as bright dots) orbiting it.

Jupiter's Rotation, by Vishal Sharma, India

Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons: Jupiter’s Rotation, by Vishal Sharma, India. This time-lapse beautifully shows the rotation of Jupiter and the passage of two Galilean moons on the right side of the frame. Jupiter completes one rotation in just under 10 hours and we see as the Great Red Spot makes its way from left to right. The two moons travel a noticeable fraction of their orbit in this short time. This image was taken in 2020 in the North of India.
Credit: Vishal Sharma/IAU OAE

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The planet Jupiter, seen here as a bright disk, is orbited by the four Galilean moons, seen here as bright dots

Jupiter Moons Movie2, by Nicolas Hurez, Paul-Antoine Matrangolo, and Carl Pennypacker, United States of America

Caption: Second place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This sequence shows the orbit of the four Galilean moons around the planet Jupiter. Almost two entire orbits of the innermost moon, Io, can be seen, with the other moons (Europa and Ganymede, but in particular Callisto) being further away, orbiting noticeably slower. The images were obtained in 2018 with the Las Cumbres Global Observatory at different locations on Earth, allowing a continuous sequence of images over approximately half a week without gaps during the day. With clear skies and over the course of several nights, the motion of the Galilean moons can also be observed with binoculars (ideally steady your elbows on a surface).
Credit: Nicolas Hurez, Paul-Antoine Matrangolo and Carl Pennypacker/IAU OAE

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Jupiter with coloured horizontal bands of clouds. The shadow of the moon Io is seen as a dark circle in the top left

Jupiter, Io and its shadow, by Ralf Burkart, Germany

Caption: First place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This time-lapse of Jupiter taken in 2017 from Germany beautifully illustrates the transit of one of the Galilean moons, Io, in front of Jupiter. As this is simply a moon casting a shadow on a planet it is equivalent to a lunar eclipse on Earth observed from further away. While the shadow of the moon is clearly visible from the beginning, it might be difficult to spot the moon itself against the background of the beautiful atmospheric bands of Jupiter the first time the video is seen. Watching it repeatedly allows appreciating the rapid motion and rotation in this fantastic observation.
Credit: Ralf Burkart/IAU OAE

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The planet Jupiter with horizontal cloud ribbons and the great red spot


Caption: This full disk view of Jupiter was obtained on 21 April 2014 with Hubble's Wide Field Camera 3 (WFC3). It shows the prominent great red spot, a gigantic cyclone. Cloud ribbons cover the surface, whose colours stem from gases like ammonia and other chemical compounds.
Credit: NASA, ESA, and A. Simon (Goddard Space Flight Center) credit link

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The Milky Way rises from the horizon over a landscape with trees, water and the distant glow of city lights

Flowing Night Sky

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   This time-lapse was shot from Slovakia in August 2020. By fixing the relative movement of the sky to Earth's rotation in some of the frames, we can experience a different perspective as a viewer. The Milky Way, our home galaxy, is visible throughout the whole video. The bright objects near the Milky Way are Jupiter and Saturn, close together, Jupiter being the brighter one. This video also shows the interaction of amateur astronomers observing the Perseids meteor shower with their telescopes pointed towards the sky. An unfortunate aspect of the art of astronomical observing, clouds can suddenly cover the whole sky. The fog occurs mostly because of the higher humidity after the rain. Most of the light trails in the sky are made by satellites, but some of them, appearing just very briefly and not very noticeably, are meteors, as the video was shot around the peak of Perseids meteor shower.
Credit: Robert Barsa/IAU OAE

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Over trees with thick trunks, the Milky Way, with several bright objects left and right, is bisected by a wide dark line.

Milky Way over Avenue of Baobabs

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image, taken from the Avenue of Baobabs, Morondava, Madagascar, in July 2017, shows the majestic band of the Milky Way, our home galaxy, together with a rich collection of constellations and asterisms: Crux, Centaurus, Scorpius, Sagittarius and the Teapot asterism. Towards the bottom left of the image we can see the Southern Cross and the pointer stars Alpha (the brighter of the two) and Beta Centauri, which help to distinguish it from similar-looking configurations. Some cultures in Africa associate the Southern Cross with a giraffe, while others associate the constellations with a pride of lions or even with the Tree of Life. Antares, the brightest star in the constellation Scorpius, is the orange-red star straight up from the middle baobab tree. To the Pokomo people from southwestern Kenya, Africa, the Milky Way is associated with the smoke emanating from a campfire lit by ancient people. The various people in South Africa, in contrast, have different star tales; the Khoikhoi from the region around Cape Town explained the colours of the red and white stars as red and white roots that were roasted on a fire and thrown towards the sky together with the ashes of the fire. The Xhosa from further east consider the Milky Way the raised bristle of a huge angry dog, while the Zulu from near Johannesburg interpret it as a stream of spears of their strongest warriors. Polynesian people, who were adept seafarers and navigators, see the constellation Scorpius as a fish hook, and refer to it as the demigod Maui’s Fish Hook. For the Djab Wurrung and the Jardwadjali people, the Southern Cross is part of a Dreamtime Story involving Tchingal, the Bram-bram-bult brothers (the pointer stars), their mother Druk (Delta Crux), and Bunya, the hunter who gets changed into a possum (Gacrux, red star at the top of the Southern Cross). In this image, the planets Saturn (the bright point above Antares) and Jupiter (the bright point at the bottom-right of the image close to the trunk of the baobab tree) are visible. Indigenous cultures have various stories associated with the planets, for example Kamilaroi and Wailan people associate Saturn with wunygal, a small bird. The Boorong people of Western Victoria associate Jupiter with Ginabongbearp, the chief of the old spirits (Nurrumbunguttias), who takes the totemic form of the sulphur-crested white cockatoo.
Credit: Amirreza Kamkar/IAU OAE

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An all-sky image showing the Milky Way as a diffuse river of light, broken only by a mottled central band of dark patches

The Milky Way Across the Zenith

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This all-sky image shows our home galaxy, the Milky Way, crossing the zenith, the point just above the observer as seen from Nagano, Japan, in May 2019. Such images of the whole sky can be taken either with a fish-eye lens or with a convex mirror on the ground, the latter of which would show the photographer as well. Some of the brightest stars in the night sky can be seen in this image, as well as two of the giant planets of our Solar System: Jupiter, the brightest point in the bottom of this image, and Saturn, another bright point just to the opposite side of the Galaxy, to the bottom and next to the horizon. Directly right of the Milky Way and below Jupiter, we can spot the bright red star Antares, the primary star of the Japanese asterism of The Heart. Japanese constellations derive from ancient Chinese constellations, which were adopted with only slight or no changes. In this tradition, The Heart is the heart of the “Azure Dragon”, a super-constellation that represents the spring. In the Babylonian and Greco-Roman traditions, this area is considered the heart of the Scorpion. In Babylonian religion, the star is associated with Lisi, the child of the mother goddess, but in Greek mythology it is related to the planet Mars, because of its colour. The reddish colour also led to the star’s Chinese name “The Fire Star”. We know that this colour is caused by its relatively cool temperature. Going from Antares to the right of the image, we find the more northern parts of the sky. The bright star in the lower-right of the image, close to the horizon, is Arcturus, located in the modern constellation Boötes. While Antares and its surrounding area are considered the heart of the Azure Dragon, Arcturus and Spica (below the horizon) are two single-star asterisms forming its huge horn. Pointing towards it from above, at the right-hand edge of the image’s horizon, we can see the handle of the Big Dipper, or Plough, which is part of the constellation Ursa Major. The bright point to the right of the galaxy and just above the middle of the image is Vega, located in the modern constellation Lyra. Extending a line to the other side of the Galaxy and a bit lower in the image we can find Altair, in the constellation Aquila. From that point we extend another line to Deneb, the brightest star in the constellation of the Swan, also a bit higher in this image and completely flooded by the Milky Way. These three bright stars comprise the asterism known as the Summer Triangle in the northern hemisphere.
Credit: Ohnishi Kouji/IAU OAE

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The bright Moon illuminates a beach. Three bright planets form a line below and to the right of the Moon.

To guard the Stars and the Sea Together

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns. This image composition is amazing. In the far background of the landscape we see a chain of mountains that seems to mirror the structure of the Milky Way in the sky above. The strong daylight-like colours of the landscape are caused by the Moon, the bright light at the top of the image. Taken in Kinabalu, Malaysia, in February 2019, this image shows the alignment of planets and the Moon, conveying the idea of the ecliptic as the central line of the Zodiac, the plane within which all planets orbit the Sun. The ecliptic is the central line of the Zodiac, so the region of about five to 10 degrees either side of the ecliptic is where the constellations of the Zodiac are located. Starting from the horizon towards the bottom left of the image we can see the planets Venus, Saturn and Jupiter. The planets have different cultural significance for people around the world, and are deeply embedded in social, religious and practical aspects of life. For example, Wardaman traditions of Indigenous Australians associate the planets with ancestor spirits who traverse the Celestial Road (ecliptic). The appearance and disappearance of planets in the sky are associated with various ceremonies. For example, when Venus starts being the “Morning star” after having been the “Evening star”, this marks the Banumbirr ceremony for the Yolnu people of Arnhem Land, in Australia. The image also shows the constellations Scorpius, Aquila, Lupus and Triangulum Australe, the asterism of the Teapot, and the two pointer stars Alpha and Beta Centauri. The constellations, asterisms and individual stars within them have significance in many different cultures. Malaysia, being close to the equator, has had connections to the north as well as to the south and almost the whole sky is visible over the course of the year. The star Antares is seen by the Kokatha people of the Western Desert as Kogolongo, the red tailed black cockatoo, while the Boorong refer to it as Djuit, the red-rumped parrot. The two stars which form the stinger of Scorpius (Shaula and Lesath), are called Karik Karik, the Australian Kestrel.
Credit: Likai Lin/IAU OAE

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Orion appears as an hourglass shape of stars in the bottom of the image. Above Taurus is v-shaped with a small star cluster

Romanian Orion

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in Romania in August 2012, this image shows two of the most recognisable constellations in the sky, Orion and Taurus. Orion, the Hunter, is found near the horizon. The most prominent star visible in this image is Betelgeuse, while the asterism of Orion’s belt is formed by three aligned bright stars. Just above Orion we can find Taurus, one of the constellations of the Zodiac. As the Zodiac is inherited from Babylon, The Bull of Heaven represents a mighty but dangerous creature that was defeated by King Gilgamesh and his friend Enkidu. They cut the Bull in half and sacrificed the animal to the gods in order to protect their people. Taurus is also home to the star cluster Pleiades, also known as the Seven Sisters. Two planets are visible: Venus, the bright spot near the fence, and Jupiter, the bright spot at the top, next to the Bull’s face. Different cultures have included the stars of these constellations in their own mythology. The Romanians, for instance, after Christianisation identified four other constellations using some of the stars of Orion and others surrounding it. One such constellation is called Trisfetitele (the Three Saints), which is associated with the three stars comprising Orion's Belt, representing the Three Hierarchs Basil, Gregory and John. This same asterism is also called Three Wise Men, Kings from the East or just Three Kings — all of these names being rooted in the Christian religion. The agricultural calendar, in contrast, led farmers to define two other constellations, the Little Plough and the Sickle. Both are seen in the southern half of the Orion rectangle; the Little Plough is drawn by connecting the southern quadrilateral with Orion’s left shoulder, and the Sickle is formed by connecting Orion’s left foot (Rigel) with the belt stars, forming an arch and completing the form of a hoe. In the cultural calendar, these constellations were used to announce the harvest of wheat/grain. Finally, the fourth Romanian constellation is the Great Auger, where Orion’s belt represents the handle of the auger, and Betelgeuse is the tip, facing towards Pollux in Gemini. This constellation is associated with treasure, as Romanian peasants believe that the Auger points to the treasure when they approach the end of the world. Most of the official star names in Orion are Arabic; Mintaka (meaning “belt”) is at the waist; Alnitak (meaning “girdle”) and Alnilam (meaning “string”) are at the belt; and Rigel (meaning foot) is at the left foot. The star on the left shoulder is named Bellatrix, the Latin term for a female warrior. The star at the right leg is called Saiph, for the sword or sabre of the Arabic Orion.
Credit: Alex Conu/IAU OAE

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The Milky Way appears as two vertical diffuse bands of light either side of a dark line, over a rocky outcrop.

The Pillar of Creation

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image shows the night sky over Tre Cime di Lavaredo, (Dolomites Natural Park), in the region of Veneto, Italy, in October 2021. The bright spot on the left-hand side is the planet Jupiter, appearing in the constellation Capricorn. To the right of Jupiter and below the two horn stars of Capricorn is the planet Saturn. Just above Jupiter we can see parts of Aquarius, one of the largest constellations and also part of the Zodiac. North of these constellations, left of the Milky Way, there are mostly faint stars. The brighter whitish one in the top left corner is Enif, a binary star in the constellation Pegasus. The Milky Way seems to emerge from a rock like celestial vapour. Roughly centred in the image are two bright stars left and right of the Milky Way: Altair and Vega, respectively. They seem to be separated by the galactic stream, as told in a popular Chinese folk story where they represent a loving couple. Today, in popular astronomy, the fairly bright star at the upper edge of the photograph is added to form a huge triangle with them, the Summer Triangle in the northern hemisphere. Altair is the brightest star of the Babylonian constellation Aquila, the Eagle. In ancient Babylon, it was said that the Eagle was carrying king Etana up in the air so that he could see Earth from above. Next to the Babylonian Eagle was the constellation of the Corpse, that returned only in Roman times when Ptolemy put it below the Eagle as the new sub-constellation “Antinous”. It is seen as the corpse (or soul) of the Roman emperor Hadrian’s favourite who had just died in the Nile. Vega is the bright white star to the right of the Milky Way. It forms part of the small constellation Lyra, famous for hosting the Ring Nebula, which is an impressive planetary nebula — a dying star blowing its gas into space. At the right edge of the image, three stars in a bent row appear rather prominently. This is the handle of the Big Dipper pointing downwards to a bright star close to the horizon: Arcturus, the bright star of the constellation Bootes (Greek: the Ploughman). This kite-like constellation is probably a pagan interpretation of the Babylonian god “Enlil” whose constellation also occupied that place in the sky. The Romans re-interpreted this figure as The Ox-Driver who controlled the Seven Oxen seen in the bright stars of Ursa Major. Directly right of Vega, there is the huge constellation Hercules and below it, directly to the left of Bootes, we find a half-circle of stars comprising the small constellation Corona Borealis, associated with Ariadne, daughter of King Minos of Crete in Greek culture. The lights seen in the bottom left side of the image are due to the reflection of artificial lights in the clouds.
Credit: Giorgia Hofer/IAU OAE

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Three bright objects in the sky with one top left, one in the middle and one lower centre.

Jupiter, Venus, Moon Conjunction

Caption: Captured with a smartphone in February 2023, over the skies of Luzerne County, Pennsylvania, USA, this photograph offers a glimpse into a conjunction, an enthralling astronomical phenomenon that occurs when two or more celestial objects are seen in close proximity in the sky from our perspective, despite the objects not being physically near to each other. In this image, the brilliance of Jupiter (top), the allure of Venus (middle), and the familiar glow of our Moon (bottom) dance together against a backdrop of delicate clouds and a treeline silhouette, making it a moment worth treasuring.
Credit: Joslynn Appel/IAU OAE (CC BY 4.0)

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A person stands next to a snowy lake. The Milky Way stretches from the top of the image to the horizon.

Milky Way Stargazer

Caption: In May 2020, atop Mount Gongga in Sichuan, China, a lone observer stands amidst the cool night air at high altitude. Looking up, they witness the grand arc of the Milky Way stretching across the sky, captured using a smartphone set to panorama mode. This image was taken far away from the city lights at an elevation of 4200 metres, where the quiet of the mountains accentuate the connection between Earth and the vast cosmos. Jupiter, a bright planet, can be seen alongside the central bulge of the Milky Way, while a subtle green airglow on the horizon adds an intriguing touch to the scene.
Credit: Jianfeng Dai/IAU OAE (CC BY 4.0)

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