Our Solar System .... Venus.
Venus, the jewel of the sky, was once know by ancient astronomers as the morning star and evening star.
Early astronomers once thought Venus to be two separate bodies.
Venus, which is named after the Roman goddess of love and beauty, is veiled by thick swirling cloud cover.
Astronomers refer to Venus as Earth's sister planet. Both are similar in size, mass, density and volume.
Both formed about the same time and condensed out of the same nebula.
However, during the last few decades scientists have found that the kinship ends here.
Venus is very different from the Earth. It has no oceans and is surrounded by a heavy atmosphere composed mainly
of carbon dioxide with virtually no water vapour. Its clouds are composed of sulphuric acid droplets.
At the surface, the atmospheric pressure is 92 times that of the Earth's at sea-level.
Venus is scorched with a surface temperature of about 482° C (900° F). This high temperature is primarily due to
a runaway greenhouse effect caused by the heavy atmosphere of carbon dioxide. Sunlight passes through the atmosphere
to heat the surface of the planet. Heat is radiated out, but is trapped by the dense atmosphere and not allowed
to escape into space. This makes Venus hotter than Mercury.
A Venusian day is 243 Earth days and is longer than its year of 225 days.
Oddly, Venus rotates from east to west. To an observer on Venus, the Sun would rise in the west and set in the east.
Until just recently, Venus' dense cloud cover has prevented scientists from uncovering the geological nature
of the surface. Developments in radar telescopes and radar imaging systems orbiting the planet have made it possible
to see through the cloud deck to the surface below.
Four of the most successful missions in revealing the Venusian surface are NASA's Pioneer Venus mission (1978),
the Soviet Union's Venera 15 and 16 missions (1983-1984), and NASA's Magellan radar mapping mission (1990-1994).
As these spacecraft began mapping the planet a new picture of Venus emerged.
Venus is scarred by numerous impact craters distributed randomly over its surface.
Small craters less that 2 kilometres (1.2 miles) are almost non-existent due to the heavy Venusian atmosphere.
The exception occurs when large meteorites shatter just before impact, creating crater clusters.
Volcanoes and volcanic features are even more numerous. At least 85% of the Venusian surface is covered with
volcanic rock. Huge lava flows, extending for hundreds of kilometres, have flooded the lowlands creating vast plains.
More than 100,000 small shield volcanoes dot the surface along with hundreds of large volcanos.
Flows from volcanos have produced long sinuous channels extending for hundreds of kilometres,
with one extending nearly 7,000 kilometres (4,300 miles).