Glossary term: Vénus

Description: Vénus est la deuxième planète la plus proche du Soleil. Souvent appelée la jumelle de la Terre, c'est une planète rocheuse et terrestre dont le rayon est légèrement supérieur à 6 000 kilomètres (km), soit environ 95 % du rayon de la Terre. Sa masse est 0,815 fois celle de la Terre. L'atmosphère de Vénus est 90 fois plus dense que celle de la Terre. Elle est principalement composée de dioxyde de carbone et d'épais nuages d'acide sulfurique qui recouvrent toute la surface. L'atmosphère épaisse produit un effet de serre très important, qui se traduit par une température de surface de 460 degrés Celsius.

Sa distance typique par rapport au Soleil est de 108 millions de kilomètres, soit environ 0,72 unité astronomique (distances Terre-Soleil). Il lui faut 224,7 jours pour parcourir une orbite. Vénus met beaucoup de temps à tourner une fois sur son axe par rapport aux étoiles lointaines ; un jour de Vénus correspond à 243 jours terrestres. C'est plus long que le temps nécessaire à Vénus pour effectuer une orbite autour du Soleil. Vénus n'a pas de lunes connues.

Vénus doit son nom à la déesse romaine de l'amour. Vénus étant très proche du Soleil, elle est souvent visible dans le ciel nocturne peu avant le lever ou après le coucher du Soleil. À ces occasions, Vénus est remarquablement brillante, même à l'œil nu, et est traditionnellement appelée étoile du matin ou étoile du soir, respectivement. Avec des jumelles, Vénus présente des phases similaires à celles de la Lune.

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

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".

Related Media

La planète Vénus montrant les nuages blancs qui l'enveloppent

Vénus en lumière visible

Caption: Cette photo prise par la sonde Mariner 10 de la NASA montre à quoi ressemble la planète Vénus lorsqu'on l'observe à l'œil nu. Vénus est enveloppée d'une épaisse atmosphère nuageuse dominée par le dioxyde de carbone, qui ne laisse jamais apparaître sa surface brûlante.
Credit: NASA/JPL-Caltech credit link

License: PD Public Domain icons

La surface de la planète Vénus avec des crêtes et des vallées

La surface de Vénus

Caption: Cette image est un rendu assisté par ordinateur de la surface de la planète Vénus. La lumière visuelle ne pouvant pénétrer les épais nuages de l'atmosphère de Vénus, l'image a été obtenue à l'aide d'ondes radio. La sonde spatiale Megallan de la NASA, lancée en 1989, a cartographié la surface de Vénus entre 1990 et 1994.
Credit: NASA/JPL credit link

License: PD Public Domain icons

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

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

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

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

Vénus, qui était petite et presque pleine, devient grande et n'est plus éclairée que par un mince croissant.

Une question de perspective

Caption: Second prix du concours d'astrophotographie 2023 de l'UAI OAE, catégorie Images fixes des phases de Vénus : Une question de perspective, par Christofer Baez La deuxième place dans la catégorie Images fixes des phases de Vénus revient à cette exquise série d'images, photographiées depuis Saint-Domingue, en République dominicaine, entre le 17 décembre 2019 et le 25 mai 2020. Alors que Vénus et la Terre gravitent autour du Soleil, nous observons différentes portions de la moitié ensoleillée de Vénus, similaires aux phases de la Lune. La séquence montre clairement que Vénus est lointaine, petite, brillante et gibbeuse dans les images du bas, et se termine par Vénus atteignant la plus grande taille apparente de toutes les planètes (images du haut), très proche du Soleil avec une petite élongation, et apparaissant comme un mince croissant. Dans la dernière image, seulement 2,8 % de la surface de la planète est éclairée.
Credit: Christofer Baez/UAI OAE (CC BY 4.0)

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

At the top Venus is full and appears small. As the images progress it moves to half, crescent and new, appearing larger.

Phases of Venus

Caption: This is a mesmerising series of images of Venus captured from Surgères, Charente-Maritime, France, over a period of six months in 2015. The phases appear similar to the phases we see of our own Moon and occur for similar reasons. Only half of Venus is illuminated by the Sun and, from Earth, we can sometimes only see part of that illuminated half, depending on the relative positions of the Sun, Earth and Venus. Both Mercury and Venus exhibit phases because their orbit is between the Sun and the orbit of Earth. Depending on the position of Venus relative to the Sun and Earth, Venus goes through its phases over a period of time. This sequence of images beautifully showcases the transition from the ‘gibbous’ to the slender crescents. The use of infrared filters helped to capture Venus's dense perpetual cloud cover during daylight in sharp detail, providing a glimpse into the mysterious nature of the planet’s atmosphere.
Credit: Stephane Gonzales/IAU OAE (CC BY 4.0)

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

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)

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

Mercury appears smaller and fainter than Venus. The bottom right of Venus is an illuminated crescent.

Venus and Mercury Trails

Caption: In this composite image, both Mercury (left) and Venus (right) can be seen heading into the sunset. The phases of each are beautifully captured as they descend. Not all planets or moons in the Solar System show phases as viewed from Earth. This phenomenon occurs because the orbits of Venus and Mercury are positioned between Earth’s orbit and the Sun, sometimes allowing us to see only part of the illuminated portion of each planet. These phases are similar to the phases we see of our own Moon.
Credit: Marcella Giulia Pace (CC BY 4.0)

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

Related Activities

Children's Planetary Maps: Venus

Children's Planetary Maps: Venus

astroEDU educational activity (links to astroEDU website)
Description: Learn more about our nearest neighbour

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

Tags: Planetary cartography , Spatial thinking
Age Ranges: 6-8 , 8-10 , 10-12 , 12-14
Education Level: Middle School , Primary , Secondary
Areas of Learning: Social Research
Costs: Low Cost
Duration: 2 hours
Group Size: Group
Skills: Analysing and interpreting data , Asking questions , Communicating information , Constructing explanations , Developing and using models , Engaging in argument from evidence , Planning and carrying out investigations