Venus

Venus

Venus

venus´ sign

Venus is the goddess of love and beauty. In Greek: Aphrodite; Babylonian: Ishtar. The planet probably got its name because our ancestors thought it was so beautiful, and it was usually the brightest object in the night sky. The surface features on Venus are named after female figures.

Venus is the second planet in order of distance from the Sun, and the sixth largest. Venus´orbit is the most nearly circular of any planet, with eccentricity of only 0.007.
                         diameter:    12.104 km (7523 miles)
                 mass, Earth=1   0.815
                               orbit:    108.200.000 km (0.72 AU)

Venus has been known since prehistoric time. The Moon and the Sun are the only brighter objects in the sky. Formerly it was thought to be two separate bodies, but the Greek astronomers knew better. As a morning star Venus was called: Eosphorus and as an evening star: Hesperus.

As an inferior planet, Venus shows phases like the Moon and and Mercury and it can be seen through a telescope from the perspective of Earth. Galileo´s observations of this phenomenon was an important evidence in favour of Copernicus´s heliocentric theory of the solar system.

The first spacecraft to visit Venus was Mariner 2 in the year 1962. The first spacecraft to land on another planet was the Soviet Venera 7 and then followed another Venera. Venera 9 which returned the first pictures of the surface. Most recently the spacecraft Magellan produced detailed maps of the surface using radar.

Venus´ rotation is very unusual. It is both very slow and slightly longer than the Venus´ year, also it is retrograde. In addition, the periods of Venus´ rotation and of its orbit are synchronised such that it always present the same face toward to the Earth when the two "sister planets" are at their closest approach. Whether this is a resonance effect or merely coincidence is not yet known.

The Earth and Venus are sometimes regarded as sister planets. In some ways are they very similar. For example: Both have only few craters indicating relatively young surfaces, Venus is slightly smaller than the Earth (95% of Earth´s diameter, 80% of Earth´s mass). Their densities and chemical compositions are very similar. Because of these similarities, it was formerly thought that below Venus´ dense clouds there might be very Earthlike landscape, and there might even life exist. But furthermore and more detailed study revealed that Venus is like hell against the paradise on the Earth.

The pressure of Venus´ atmosphere at the surface is like 90 Earth atmospheres. That is about the as the pressure a a depth of 1 km in Earth´s oceans. It is mostly composed of Carbon Dioxide, which make the greenhouse effects here on Earth. There are several clouds many kilometres thick composed of sulphuric acid. These clouds obscure the view to see the surface.

Venus´ surface temperature is about +480°C, which is enough to melt lead. So Venus is hotter than Mercury despite being two times further away from the Sun.

Venus probably once had large amounts of water like Earth but it all boiled away. Venus is now quit dry, but it rains there sulphuric acid, which burns holes in the spacecraft's that visit Venus.

Most of Venus´ surface consist of gently rolling plains with little relief. But there are also few broad depressions: Guinevere Planitia, Lavinia Planitia, and Atalanta Planitia. There are two large highland areas, they are Isthar Terra in the northern hemisphere, which is about the size of Australia. And also the Aphrodite Terra along the equator, which is about the size of South America. The interior of Ishtar consists mainly of a high plateau. The Lakshmi Planum surrounds the highest mountains of Venus including the enormous Maxwell Montes

There are several shield volcanoes, like Olympus Mons on Mars and Mauna Kea at Earth, on Venus and few of them are still active on the Venus´ hot spots. Data from the Magellan radar imaging confirm that Venus is covered by lava flows. But the past few hundred million years have been geologically quiet.

There are no small meteor craters on Venus. The meteors burn up in Venus´ dense atmosphere before they reach the surface.

The oldest terrain's on Venus are probably 800 million years old.

Radar images from the Magellan spacecraft show some unique features, like pancake volcanoes. They seem to be eruptions of very thick lava and coronae which seem to be collapsed domes over large magma chambers.

Due to its slow rotation, Venus has no magnetic field.

Venus has no satellites, and thereby hangs a tale.