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مصطلح في المعجم: كوكب الزهرة

ويُعرف أيضًا باسم الزهرة، نجمة الصباح، نجمة المساء.

الوصف: الزهرة هو ثاني أقرب كوكب إلى الشمس. يُطلق عليه أحياناً "توأم الأرض" لأنه كوكب صخري (أرضي) نصف قطره يزيد قليلاً عن 6000 كيلومتر، أي نحو 95% من نصف قطر الأرض، وكتلته تعادل 0.815 من كتلة الأرض. غلافه الجوي أكثر كثافة من غلاف الأرض بنحو 90 مرة، ويتكون أساساً من ثاني أكسيد الكربون، مع سحب كثيفة من حمض الكبريتيك تغطي كامل سطحه. ينتج عن هذا الغلاف الجوي الكثيف تأثير احتباس حراري قوي جداً، يرفع درجة حرارة سطحه إلى نحو 460 درجة مئوية.

يبعد الزهرة عن الشمس في المتوسط 108 مليون كيلومتر، أي ما يعادل 0.72 وحدة فلكية (المسافة بين الأرض والشمس). يحتاج إلى 224.7 يوماً لإكمال دورة واحدة حول الشمس. ويستغرق وقتاً طويلاً للدوران حول محوره بالنسبة إلى النجوم البعيدة؛ إذ يعادل اليوم على الزهرة (مدة دورانه حول نفسه) 243 يوماً أرضياً، وهو أطول من مدته في الدوران حول الشمس. الزهرة لا يملك أي أقمار معروفة.

سُمّي الزهرة باسم إلهة الحب عند الرومان. وبسبب قربه من الشمس، يمكن رؤيته كثيراً في السماء قبل شروق الشمس أو بعد غروبها مباشرة، حيث يكون لامعاً بشكل واضح حتى بالعين المجردة، ويُعرف في هذه الحالات باسم "نجمة الصباح" أو "نجمة المساء". وعند رصده بالمنظار، يمكن ملاحظة أن له أطواراً مشابهة لأطوار القمر.

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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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وسائط ذات صلة


The planet Venus showing white clouds enshrouding the planet

Venus in visible light

الشرح: This picture taken by NASA's Mariner 10 probe shows what the planet Venus looks like when looking at it with naked eyes. Venus is enshrouded inside a thick cloudy atmosphere dominated by carbon dioxide, never revealing its hot surface.
المصدر: NASA/JPL-Caltech رابط المصدر

License: PD الملكية العامة أيقونات


The planet Venus' surface with ridges and valleys

Venus' surface

الشرح: This image is a computer-aided rendering of the surface of the planet Venus. Since visual light cannot penetrate the thick clouds in Venus' atmosphere, the image was obtained with radio waves. NASA's space probe Megallan, launched in 1989 mapped Venus' surface between 1990 and 1994.
المصدر: NASA/JPL رابط المصدر

License: PD الملكية العامة أيقونات


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

الشرح: 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.
المصدر: Likai Lin/IAU OAE

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


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

الشرح: 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.
المصدر: Alex Conu/IAU OAE

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


Venus changes from being small and almost full to being large with only a thin crescent illuminated.

A Matter of Perspective

الشرح: Second place winner in the 2023 IAU OAE Astrophotography Contest, category of Still images of phases of Venus. This exquisite series of images, captured from Santo Domingo, Dominican Republic, between 17 December 2019 and 25 May 2020, shows the phases of Venus as seen from Earth. As Venus and Earth orbit the Sun, we observe different portions of Venus’s sunlit half, similar to the Moon’s phases. The sequence clearly shows Venus as distant, small, bright and gibbous in the lower frames, and ends with Venus reaching the biggest apparent size of all planets (upper frames), very close to the Sun with a small elongation, and appearing as a thin crescent. In the last frame, only 2.8% of the planet’s surface is illuminated.
المصدر: Christofer Baez/IAU OAE (CC BY 4.0)

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

الأنشطة المرتبطة


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 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
وسوم: Planetary cartography , Spatial thinking
الفئات العمرية: 6-8 , 8-10 , 10-12 , 12-14
المرحلة التعليمية: المرحلة المتوسطة , المرحلة الابتدائية , المرحلة الثانوية
مجالات التعلم: تعلم منظم قائم على الاستقصاء
التكاليف: تكلفة منخفضة
المدة: ساعتان
حجم المجموعة: جماعي
المهارات: تحليل البيانات وتفسيرها , طرح الأسئلة , توصيل المعلومات , صياغة التفسيرات , تطوير النماذج واستخدامها , بناء حجج استنادًا إلى الأدلة , تخطيط وتنفيذ التحقيقات