) Venus (

The closest planet to the Earth is little known. While it may reach a proximity of 40M km, Venus is shrouded in mist. The cloud blanket which covers the surface, reflecting the Sun's light and hence making Venus very bright in the Earth's night sky, has prevented any detailed knowledge of the surface of the planet. What is known is that the planet is both peculiar, and hostile.

Of the 12 Russian spacecraft, and the many American machines sent to investigate the planet, only a few have landed. Venus's atmosphere is made up suffocating carbon dioxide, sulphuric acid and liquid sulphur droplets. No life can exist there. The surface temperatures reach 600C and the pressure at the surface is 90 times that of the Earth. The planet is also known to have a very slow rotation (once every 243 days) and actually rotates backwards compared to all the other planets in the Solar System.

As far as the surface of the planet is concerned, pictures have shown a barren, rocky landscape, with possible rift valleys and plate activity.

The differences between Venus and the Earth have posed many questions. Why should such a nearby planet be so unusual and hostile? The hot temperatures have been put down to the carbon dioxide in its atmosphere, which creates a kind of Venusian greenhouse effect. But as yet, there are few real answers to the other questions. Perhaps when more is known about this hostile neighbour planet, more will be known about the origin of our own world.