Venus: Earth's Twin Sister

A 3D rendering of Venus.

Venus is the sixth largest planet in the Solar System and the second planet from the Sun. Named after the Roman goddess of love and beauty, Venus has the longest rotation period of any planet in the Solar System, which is equivalent to 224.7 Earth days. Venus rotates in the opposite direction of the other planets, including Earth, and is the second-brightest object on the night sky, after the Moon, but does not have any natural satellites of its own. The planet has a dense atmosphere that is composed of 3.7% nitrogen and 96.5% carbon dioxide, and has an atmospheric pressure that is 92 times greater than Earth's. Also a terrestrial planet, and similar in size, mass, and proximity to the Sun, Venus is sometimes referred to as Earth's "sister planet."

Why Are Earth and Venus Known As Twin sisters?

Venus and Earth are sometimes referred to as planetary sisters or twins because they are similar in bulk composition, proximity to the Sun, mass, and size. The mean diameter of Venus is 7,520.8 miles, while Earth’s diameter is 7,926.3 miles. Earth is about 5% bigger than Venus, which compared to other planets, is a very small difference. Earth weighs approximately 19% more than Venus, and the two planets both have metal cores that are covered by silica rock mantles and a thin crust. However, despite the many similarities between these two planets, Venus and Earth are also different in many ways. For example, Venus is the hottest planet in the Solar System, with an average temperature of about 462 °C.

Geography of Venus

Over 80% of the surface of Venus is covered by volcanic plains. More specifically, 10% of the planet's surface is covered in lobate or smooth plains, while 70% is covered in plains with wrinkle ridges. Venus has two highland "continents", one located just south of its equator and the other in the planet's northern hemisphere. The northern continent is named Ishtar Terra, is roughly the size of Australia, and contains the highest mountain on Venus, known as Maxwell Montes. The other continent is named Aphrodite Terra, and is the larger of the two highland continents. Venus has very few impact craters, meaning that its surface is relatively young, with an estimated age of 600 million years old. The planet also has numerous unique surface features, including valleys, mountains, and craters. Venus has countless flat-topped volcanic features, called "farra," which resemble pancakes, and are between 330 ft and 3,280 ft in height and between 12 miles and 31 miles acrooss. Another volcanic feature observed on Venus are novae, which have both concentric and radial fractures that resemble spider webs. Venus has more volcanoes than Earth, with a total of 167 large volcanoes that measure more than 62 miles across. To a naked eye, Venus appears as a white light that is brighter than all other planets and stars, except for the Sun.

Rotation and Orbit

Venus rotates around the Sun at a distance of approximately 67 million miles and completes an orbit every 224.7 Earth days. All planetary objects in the Solar System rotate in an anti-clockwise direction, except Venus, which rotates clockwise. Earth’s equator rotates at 1,037.6 mph, while Venus rotates at 4.05 mph. Since Venus rotates slowly, the planet is nearly spherical. A Venusian year has 1.92 Venusian solar days, and if observed on Venus, the Sun rises in the west and sets in the east. Venus does not have any natural satellites but instead has numerous Trojan asteroids.


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