2007-04-18 06:54:21 · 3 answers · asked by girl 1 in Science & Mathematics ➔ Astronomy & Space
"Venus has striking surface characteristics, which are as beautiful as they are unusual. The majority of what we know today about its surface stems from radar observations, mainly images sent by the Magellan probe from August 16, 1990, until the end of its sixth orbital cycle in September 1994. Ninety-eight per cent of the planet's surface was mapped, twenty-two per cent of it in three-dimensional stereoscopic images.
The surface of Venus is covered by a dense atmosphere and presents clear evidence of violent volcanic activity in the past, including shield and composite volcanoes similar to those found on Earth.
Relative to the Moon, Mars or Mercury, Venus has few small impact craters. This is a result of the planet's dense atmosphere, which burns up smaller meteors. Venus does have more medium to large craters, but still not as many as the Moon or Mercury.
Some other unusual characteristics of the planet include features called coronae (Latin for crowns, based on their appearance), tesserae, and other figures known as arachnoids, resembling a spider's web. Long rivers of lava have been discovered, as well as evidence of Eolian erosion and tectonic shifts which have played an essential role in making the surface of Venus as complex as it is today.
Despite the fact that Venus is the planet closest to Earth (some 40 million kilometres at inferior conjunction), and is similar in size, the resemblance is superficial: no probe has been able to survive more than a few hours on its surface because the atmospheric pressure is some 90 times that of the Earth's. The temperature on the surface is around 450°C (842°F). This is mostly caused by the greenhouse effect created by an atmosphere composed mainly of carbon dioxide (96.5%).
Ultraviolet surveys of Venus show a Y-shaped pattern of cloud formation near the equator indicating that the upper layers of the atmosphere circulate around the planet once every four days, suggesting the presence of winds of up to 500 km/h (311 mph). These winds exist at high altitudes, but the atmosphere at the surface is relatively calm, and images from the surface reveal no evidence of wind erosion"
2007-04-18 08:22:04 · answer #1 · answered by *SnowQueen* 3 · 0⤊ 0⤋
Try a search next time. It took 10 seconds
http://en.wikipedia.org/wiki/Venus
2007-04-18 14:00:05 · answer #2 · answered by Gene 7 · 2⤊ 0⤋
There is a lot of Igneous rock.
2007-04-18 14:38:08 · answer #3 · answered by Wedge 4 · 1⤊ 0⤋