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Planets and moons


Venus, as seen beneath its cloud coverVenus, as seen beneath its cloud cover Venus is the second planet from the Sun. About the same size as Earth, Venus is sometimes referred to as our sister planet. But these sisters have very little else in common. In fact, the planet named after the Roman goddess of love is almost certainly the nastiest place in the Solar System. Venus spins slowly on its axis, actually taking longer to complete one rotation than to circle the Sun. By contrast, its clouds race around the planet in just four days. Unlike all the other planets apart from Uranus, Venus spins not from west to east, but from east to west. No one knows why it spins “backwards”.

Venus, shrouded in dense cloudVenus, shrouded in dense cloud


Venus is shrouded in thick, unbroken clouds. They are made not of water but droplets of deadly sulphuric acid. Some 25 kilometres (15 miles) thick, the clouds prevent most sunlight from reaching the surface. But another kind of radiation from the Sun, infrared, does get through and Venus’s dense carbon dioxide atmosphere stops it from escaping. It is the same “greenhouse effect” as happens on Earth, but much more extreme. The result is a constant surface temperature of 490°C (914°F), the hottest in the Solar System. Even the heavy metal lead would melt in that heat.

Any water that once existed on Venus would have evaporated long ago. If any space explorer landing on Venus could somehow resist the heat, they would be suffocated by the unbreathable carbon dioxide air, dissolved by sulphuric acid and crushed by air pressure about 90 times that on Earth.

 Venera 9, the first spacecraft to capture Venus's... Venera 9, the first spacecraft to capture Venus's...

Poster for a fictional space journey to Venus's cloudsPoster for a fictional space journey to Venus's clouds

Life on Venus?

After the Moon, Venus is the brightest natural object in the night sky. It is bright enough sometimes to be seen in the middle of the day. It is often mistaken for a UFO.

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