Arpita Srivastava Content Writer
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Venus is the second planet in the solar system that lies close to the sun. It is the planet that lies before Earth and is the closest body to it apart from the Moon.
- As the orbit of Venus lies closer to the sun than the Earth, its position in the sky stays nearly the same as that of the sun.
- The planet is visible only within the hours of sunrise to sunset.
- Sometimes it is known as sister planet to Earth.
- Venus is known to be the solar system's brightest planet when the sky is clear.
- It is designated by the symbol ♀.
- The diameter of the planet is approximately equal to Earth's at 12,104 km.
- It comes under the category of terrestrial planet.
Key Terms: Venus, Solar System, Discovery of Venus, Surface Composition, Atmospheric Pressure, Satellite, Mean Temperature, Magnetic Field, Orbit, Sun, Earth, Planets
Discovery of Venus
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Venus was identified in ancient times along with four other planets – Mercury, Mars, Jupiter, and Saturn. Before the invention of sophisticated astronomical instruments, Venus’ movements were observed keenly and analyzed over centuries.
- The Babylonians recorded its appearance in around 3000 BC and compared it to the goddess Ishtar.
- Several other prominent civilizations like China, Egypt, Greece, and Central America also show astronomical records of Venus.
- In ancient Greece, Venus was known under two names, namely Phosphorus and Hesperus.
- It is called phosphorus when it appears as a morning star.
- Venus was called Hesperus when it appeared like a night star.
- The modern name “Venus” is derived from the Roman goddess of love and beauty (the Greek equivalent of Aphrodite).
- The reason is that it appears like an illuminating jewel in the sky.
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Physical Characteristics of Venus
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Some important physical characteristics of Venus are as follows:
Surface Composition
Venus’s surface was first discovered by Soviet landers. He introduced several instruments to analyze the chemical composition of its surface materials. Only a relative proportion of a few surface elements have been determined to date.
- As a result, there is no solid conclusive knowledge of rocks or minerals present on the planet.
- Two measurement methods were used to determine the concentration of the different elements on Venus.
- Gamma-ray spectrometers measured concentrations of naturally radioactive isotopes like potassium, uranium, and thorium.
- It was brought by Veneras 8, 9, and 10 and by the landers of the Soviet Vega 1 and 2.
- X-ray fluorescence instruments measured concentrations of various other major elements.
- The material was brought by Veneras 13, 14, and Vega 2.
Atmosphere and Climate of Venus
Venus is known to have the most massive atmosphere, composed of 96.5 % carbon dioxide and 3.5 % molecular nitrogen. It includes traces of other gases like sulphur dioxide, carbon monoxide, argon, helium, and water vapour.
- In comparison to the Earth, Venus has an atmospheric mass that is 93 times that of the Earth’s.
- It has a surface pressure that is about 92 times that of the Earth’s.
- The surface density is 65 kg/m3 with 6.5% that of water.
- This is equivalent to 50 times that of the Earth’s atmosphere at 293 K (20 °C; 68 °F) stumped level.
- The atmosphere rich in CO2 creates the strongest atmospheric phenomenon.
- It creates a surface temperature of a minimum of 735 K.
- Thus, the surface of Venus is even hotter than Mercury (the closest planet to the Sun), where the maximum temperature is 700 K.
- This also results in the presence of an extreme percentage of primordial noble gases in the atmosphere.
Venus
Magnetic Field and Core
Venus was found in 1967 by Venera 4. It has a magnetic flux that is much weaker than that of the Earth. Venus’ magnetic field is induced by an interaction between the ionosphere and the solar radiation.
- A possible reason for this is Venus has no solid core.
- Another reason is it is still in the cooling process, and the liquid part of the core is approximately at the same temperature.
- The theory suggests that Venus’ core has solidified, which can also be a reason for such an event.
Orbit and Rotation
Venus has a mean orbital distance of about 0.72 AU from the Sun, which corresponds to 108 million kilometres. It completes one orbit every 224.7 days.
- All the other planets that rotate in an anticlockwise direction around the Sun (as viewed from the North Pole of the Earth).
- Venus rotates clockwise in retrograde rotation once every 243 days on Earth.
- It undergoes the slowest rotation of any planet in the solar system.
- Venus has no natural satellites, although several trojan asteroids surround it, like the 2002 CK VE68 quasi-satellite.
- It has two temporary trojans, a 2001 CK32 and a 2012 XE133.
Natural Habitability in Venus
Since the 1960s, speculations of habitability on the surface of Venus have significantly decreased as it became clear that the planet’s air conditions are extreme in comparison to that of the Earth.
- The heat and air pressure on Venus makes water-based life almost impossible to exist.
- The air pressure and temperature, even fifty kilometres above the planet’s surface, are the same as that at its surface.
Venus Compared with Earth
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Venus is a neighbouring planet to Earth, and these two are called “sister planets” for multiple reasons. This is owed to their similar size, mass, bulk composition, and proximity to the Sun.
- Despite these similarities, the two have huge contrasts in several other aspects.
- Venus has the densest atmosphere among the four terrestrial planets, containing almost 96% CO2 in the air.
- Its atmospheric pressure is about 92 times the ocean level pressure on Earth.
- The mean temperature is 737 K (464 °C; 867 °F), making it the most well-liked surface among all planets in the solar system.
Venus is covered by an opaque layer of extremely reflective clouds of vitriol. This prevents the planet’s surface from being seen from space in light. It might have had oceans in the past, but these must have been vapourised due to an extreme rise in temperature.
- Venus has always been a major target for interplanetary explorations because of its proximity to the Earth.
- It is the first planet beyond Earth that a spacecraft named Mariner 2 visited in 1962.
- The primary spacecraft to have successfully landed for the first time was Venera 7 in 1970.
Things to Remember
- Venus is the second planet in the solar system, which lies close to the Earth.
- It is derived from the name of the Roman Goddess of love and beauty.
- Venus is the brightest planet in a clear sky and is considered the hottest planet in the solar system.
- The planet is composed of 96.5 % carbon dioxide, 3.5 % molecular nitrogen, and traces of other gases.
- It has an atmospheric mass that is 93 times that of the Earth’s.
- The planet consists of greenhouse gas, carbon dioxide, and a cloud of sulfuric acid.
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Sample Questions
Ques. What is the colour of Venus as seen from space?Are there volcanic activities on Venus? (3 marks)
Ans. Venus appears as a yellow planet from space because of its thick layer of carbon dioxide and sulphuric acid clouds that surround the surface of the planet. All of these together give a light yellowish appearance to Venus.
- Venus is known to have more than 1600 major volcanoes but none of them have been erupting at present.
- However, some recent studies in 2020 have suggested that Venus is currently volcanically active.
Ques. Explain the discovery of Venus? (2 marks)
Ans. Venus is the brightest planet in the night sky and can be easily spotted in plain eyes. It was identified by people in ancient times during the rise of several prominent civilizations. Galileo Galilei was the first person who constructed a telescope to look at Venus in 1600. The first spacecraft that visited Venus was NASA’s Mariner 2 Aircraft in 1962. The most recent mission to Venus was NASA’s Magellan that visited and mapped the surface of Venus with the help of radar.
Ques. Why does Venus have an unusual rotation? (2 marks)
Ans. Venus shows an unusual movement in its direction and speed of rotation. The planet rotates in a clockwise direction from east to west around the Sun. It is also remarkably slow in its rotation and takes 224.7 days to complete one rotation.
Ques. What is the atmosphere of Venus composed of? (2 marks)
Ans. Venus has a massive atmosphere that is composed of 96 % carbon dioxide, 3.5 % molecular nitrogen, and traces of many other gases like carbon monoxide, sulfur dioxide, water vapor, helium, and argon.
Ques. Why does Venus have such a high temperature? (2 marks)
Ans Venus has a very thickly composed atmosphere that traps heat and keeps the planet warm. It is wrapped by an opaque layer of highly reflective vitriol clouds that do not allow the surface to be seen from space. This results in a very high mean temperature which also makes it the hottest planet in the solar system. Besides these, its proximity to the sun is also a reason why its temperature is so high all the time.
Ques. Does Venus undergo tectonic activities? (2 marks)
Ans. Yes, Venus undergoes tectonic activities, which can be concluded from the presence of folds, faults, volcanoes, mountains, and rift valleys on its surface. However, it does not undergo global tectonic activities like on earth probably because it is extremely hot and dry.
Ques. What are the similarities between Earth and Venus? (2 marks)
Ans. Earth and Venus have similarities in their masses, densities, size, and relative locations in the solar system. They also likely have the same chemical compositions overall because of their shared solar nebular formation. Because of these similarities, the two planets are often called “sister planets”.
Ques. Why is Venus called the “morning star” or “evening star”? (2 marks)
Ans. Sometimes Venus appears in the eastern sky even before sunrise. Sometimes, it appears in the western sky just after sunset. It is therefore called the “morning star” or “evening star” even though it is not a star. To locate Venus in the sky, we must try to observe it either 1-3 hours before sunrise, or 1-3 hours after sunset.
Ques. What is the period of revolution for Venus around the Sun? (2 marks)
Ans. The approximate mean orbital distance of Venus from the Sun is about 0.72 AU, which corresponds to 108 million kilometers. As a result, it completes one revolution around the sun in 225 earth days.
Ques. What is the difference between Venus and Earth? (4 marks)
Ans. The difference between Venus and Earth are as follows:
| Venus | Earth |
|---|---|
| Venus is the second planet in the solar system. | Earth is the third planet in the solar system. |
| It has a surface area of 4.60 × 108 km². | It has a surface area of 510,072,000 km². |
| Venus has a equatorial velocity of 6.52 km/h (1.81 m/s). | Earth has a equatorial velocity of 1,674.4 km/h (465.1 m/s). |
| It has a mean density of 5.204 g/cm³. | It has a mean density of 5.5153 g/cm3. |
Ques. Mention some interesting facts about Venus? (4 marks)
Ans. Some interesting facts about Venus are as follows:
- It was analysed that billion of years ago the climate of Venus is similar to that of Earth.
- Like Uranus, Venus rotates in clockwise direction.
- The planet is composed of volcanoes and mountains.
- Venera 13 of the Soviet Union survived the temperature of Venus for more than two hours.
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