Astronomy Project: “What is unique about the rotation of the planet Venus?”

Hye Jeong, Cho (Jenny)

Professor Acquaviva

Project: “What is unique about the rotation of the planet Venus?”



The only planet named after a female is named for the ancient Roman goddess of love and beauty. Venus is the brightest object in the sky after the Sun and the Moon. Venus is also the second planet from the Sun. As it is smaller than the planet Earth, it is also similar to the inside of Earth. Because of its thickness of the clouds the surface of Venus is hard to see, But the space missions that was sent to Venus showed us that the surface was covered with volcanoes and mountains. It would be hard for a human to be in, because of the temperature so high, the acid that causes the clouds to smell really bad and the atmosphere so tough. The atmosphere is made of mostly carbon dioxide and clouds of sulfuric acid covering the whole planet. The carbon dioxide and the acid make a very hot and thick atmosphere. The diameter of Venus is 12,100 km. It is about 1040 km smaller in diameter than Earth. But even though the Earth and Venus has the same inside unlike anything on the Earth, Venus has crowns ring like structures that range from roughly 95 to 360 miles if converted to kilometers it will be 155 to 580 kilometers wide. Also mentioning about the Sun, The average distance from Venus to the Sun is 108.21 million km. Venus follows an elliptical orbit around the Sun. At the closest point of its orbit is called perihelion, Venus is only 107.48 million km from the Sun. The most distant part of its orbit, Venus is 108.94 million km from the Sun. Going back to my main point on “What is unique about the rotation of the planet Venus?” Well, the planet Venus goes in a clockwise retrograde rotation. It takes Venus 242 earth days to rotate on its axis, so for an example a day on Venus is about 243 days on earth. Venus takes 224.7 days to complete one orbit around the Sun. The period of rotation for Venus is 243 days. In other words, Venus takes 243 days to turn once on its axis so that the stars are in the same position in the sky. The sun rises in the west and sets on the east in Venus. This is the slowest rate of a planet in our Solar System. If you could actually stand on the surface of Venus, with the scorching heat and the pressure of the atmosphere, you would see the Sun rise in the West and then travel slowly across the sky, to set in the East. The total time from sunrise to sunrise is 116.75 days.


Since Venus rotates in a retrograde, or opposite, direction with relation to its orbital motion about the sun so in Venus the sun rises in the west. Astronomers think that Venus was impacted by another large planet early in its history, billions of years ago. The combined momentum between the two objects averaged out to the current rotational speed and direction.  If viewed from above the Sun’s North Pole, all of the planets are orbiting in a counter-clockwise direction; but while most planets also rotate counter-clockwise, Venus rotates clockwise in “retrograde” rotation. Venus came to have a slow, retrograde rotation was a confusion for scientists when the planet’s rotation period was first measured. When it formed from the solar nebula, V

enus should have had a much faster, increased speed in rotation, but as calculations show that over billions of years, tidal effects on the atmosphere can be the reason why the planet rotates slowly. As due to the atmosphere in Venus, The surface of Venus is so hot that periodically the outer crust can melt. From the radar images of the surface, it can be seen many volcanoes. The surface is roughly divided up between 65 % rolling plains, 25 % highlands, with the rest being volcanic areas. There are two major highland, or mountainous areas. As it says on this article the first link below, it is shown that the planet Venus has rotated slower than the usual, from the measurements the scientists found out “indicate that Venus’ rotation has slowed by 6.5 minute.” The scientists thinks the atmosphere on Venus caused the rotation to slow down “ Venus’ thick atmosphere and high-speed winds could be to blame. The planet’s murky carbon dioxide-rich atmosphere gives it a surface pressure 90 times that of Earth’s” So we can conclude that the Venus’s rotation is slowed down by its atmosphere, we are not sure yet but as of the now the measurements proves that the planet had slowed down more as time passed by. A lot of the heat caused the planet to slow down, as it also rotated the opposite way. Those are the unique ways planet Venus has its rotation presented. As a planet that has no moons, Venus is often called a morning star because it orbits closer to the Sun than our planet. This causes Venus to appear in the western sky after the sun sets and rise in the East before the sun breaks the horizon.  Only the sun and the Moon are brighter in our night sky. It can also cause to cast shadows because it can be so bright.


Links references

Part two