The Planet Venus

25 September 2005 | 02:27 Code : 5872 Geoscience events
Named for the Roman goddess of love and beauty, the planet Venus is our closest neighbor, and the second brightest object in the night

Named for the Roman goddess of love and beauty, the planet Venus is our closest neighbor, and the second brightest object in the night sky, after the Moon. Because it is similar in size, composition, mass and distance from the Sun, it is sometimes referred to as Earth’s twin, but Venus is a world vastly different from our own.

Venus has no rain or ocean, and its surface consists of about 20 percent lowland plains, 70 percent rolling uplands and 10 percent highlands. It is covered by a layer of thick, rapidly rotating clouds, which trap the Sun’s heat, producing surface temperatures of about 854 degrees Fahrenheit--hotter than Mercury, the closest planet to the Sun. The clouds also reflect sunlight, making Venus the brightest planet in the sky.

The planet’s atmosphere contains carbon dioxide and sulfuric acid and has almost no water vapor. The highly dense atmosphere creates a surface pressure 90 times greater than Earth’s, resembling the pressure found deep in the Earth’s oceans. This pressure is strong enough to crush even metal, which is why the space probes that have landed on Venus are destroyed within a few hours. It also explains the lack of craters smaller than 2 kilometers across--meteors this small are incinerated in the planet’s atmosphere, never making it to the surface.

Venus seems to have had a volcanic past--its surface is marked by more than 1,000 volcanoes or volcanic centers larger than 20 kilometers in diameter, and nearly a million that are at least 1 kilometer in diameter. These volcanoes helped shape the planet’s appearance: much of its surface is covered by lava flows, and volcanic flows have created several channels that extend for hundreds of miles.

It is believed Venus contains an iron core, similar to Earth’s, that measures about 3,000 kilometers in diameter. The planet is covered primarily by a rocky, molten mantle eroded by light winds that sweep the surface at no more than a few miles an hour. Scientists think Venus was completely resurfaced between 300 million and 500 million years ago.

Venus’ movement is unlike any other planet in the solar system. The planet spins retrograde, or opposite the direction it orbits the Sun. From Venus, the Sun appears to rise in the west and set in the east. It is also one of the slowest-moving planets, taking 243 Earth days to spin on its axis. Its orbit around the Sun is only 225 days, making its day longer than its year.

Venus’ name isn’t its only tribute to women; almost all of the planet’s surface features are named after women, including Sacajawea, the American Indian who guided Lewis and Clark on their expedition; Diana, goddess of the hunt; and the mythical figures Ishtar and Aphrodite



tags: QAZVIN

Your Comment :