Venus the planet:
Venus is the second planet in our solar system and is between the Sun and the Earth’s orbit.
Easily located in our sky, Earth provides a spectacular view of the bright planet, which can be observed in the evening or before dawn. It is the purest white in color and can be found due to its fixed light in the sky.
Venus is the sixth largest planet and its orbit is the most circular of any of the planets, having an eccentricity of less than 1%.
Venus in Greek was the goddess of love and beauty and the planet was probably named that because it is the brightest of the planets known to the ancients. Also, the surface features on Venus were named for female figures, with few exceptions.
The planet has been known about since the prehistoric times, and is the brightest object in the sky besides the Sun and the Moon. It was once thought to be two separate bodies, like Mercury, but the Greek astronomers discovered that it was one body. Phases of Venus can be viewed from Earth through a telescope because it is an inferior planet. Galileo observed this phenomenon and it was important evidence to support Copernicus’s heliocentric theory of the solar system.
Venus was first visited by the Mariner 2 in 1962 and then was visited by many others after that including the Pioneer Venus, and Soviet Venera 7, as well as the Venera 9, which returned the first photographs of the surface.
Magellan, the first orbiter and US spacecraft, produced detailed maps of the surface using radar, and the ESA’s Venus Express is now in orbit with a large variety of new instruments and is expected to reach the planet in April of this year.
Venus has an unusual rotation in that it is very slow, 243 Earth days per Venus day, and it’s day is longer than its year. Venus also rotates in retrograde, or backwards, and periods of its orbit are synchronized with Earth, so the same face is towards the planet at their closest approach.
Venus is regarded as Earth’s sister planet because in many ways they are very similar. They are approximately the same size, Venus only being 95% of Earth’s diameter and 80% of Earth’s mass.
Both planets have very few craters, which indicate that their surfaces are very young. Also, Earth and Venus have very similar chemical compositions and densities. It is these similarities that led us to think that below its dense clouds, Venus might be very Earthlike, and may even have life.
However, a more elaborate study of the planet concluded that there are many important differences between the planets and that Venus may indeed be the least likely place that life could survive, or thrive.
The pressure of Venus’ atmosphere at the surface is 90 atmospheres (about the same as the pressure at a depth of one km in Earth’s oceans). The atmosphere is made up of mostly carbon dioxide and there are several layers of thick clouds that completely obscure the surface.
These clouds cause Venus to have a dramatic greenhouse effect that causes the surface temperatures to reach over 400 degrees, which is hot enough to melt lead. Venus has a surface temperature that is actually hotter than Mercury’s despite the fact that it is much further away from the Sun.
The winds in the clouds of Venus can reach hurricane force speeds, however the surface winds are fairly mild. Venus was once thought to have large amounts of water like Earth, but it has long since boiled off and now the planet is very dry. If Earth had been slightly closer to the Sun, it would have suffered the same fate.
The surface of Venus consists of gently rolling plains with broad depressions. Data from Magellan’s imaging radar shows that most of the surface is covered by vast lava flows, and there are several large volcanos, some of which are still vocanically active. Most of the planet is geologically quiet and has been for the past hundred million years.