VENUS' POISONOUS ATMOSPHERE

Venus may be the planet closest to Earth and the brightest object in the sky after the Sun and the Moon, but it was only recently that we have been able to discover what the planet's surface is like. We didn't know whether Venus was a planet covered with craters like Mercury, Mars and the Moon, whether it had hills, mountains, valleys or volcanoes, or showed any signs of life existing on its surface. This is because Venus is totally covered by a heavy cloudy shield, as shown in the picture below, taken by the Mariner 10 spacecraft in February 1974.

The swirling clouds look peaceful, but they are deinitely not! The planet receives heat from the Sun, but, because of its thick cloud cover, the heat is trapped under the cloud, unable to escape back into space as it does on Earth. This is similar to how a greenhouse works on Earth. Temperatures can reach up to 600°c. It is because of this reason that Venus is the hottest planet in the Solar System, even though it is not the closest planet to the Sun.