A quick tour of the solar system
Page 3

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The next nearest place we could visit would be Venus. This goes round closer to the Sun than Earth, and when the two planets are closest together it is 26 million miles (42 million km) away. So at a million miles an hour we could get there in just over a day.

The first thing we’d find is that from nearby, Venus is brilliant. When we see it in the evening sky it looks like a very bright star, and from close to it would be so blindingly bright that you’d have to wear very dark glasses just to be able to look at it. But you’d actually see very little, because Venus is covered by dense clouds and you’d get no views of the surface at all. We would also need a very special landing craft, because the atmosphere of Venus is much denser than that of the Earth. The only familiar thing would be your weight – it would be almost the same on Venus as on Earth as the two planets are almost exactly the same size. However, down on the surface the pressure of the atmosphere is about 90 times that on the surface of Earth, so even if the air was suitable for us your lungs wouldn’t be strong enough to breathe it and they would be crushed instantly.

To make matters worse the air is almost completely carbon dioxide, with no oxygen, so you’d suffocate as well. And the temperature is about 400º C, double the temperature of your oven*, so you’d be fried too. Mixed in with the clouds is sulphuric acid, so all in all it’s not the place to go visiting. But not surprisingly, no one has ever visited Venus, and even the few space probes that have got there lasted only a short while before packing up.

Our best views of Venus have come from spacecraft equipped with radar, which have revealed a landscape of volcanoes. Probably some are still active. On the surface the Sun isn’t visible through the dense clouds, and even though Venus is closer to the Sun the light is as dim as a cloudy winter’s day on Earth. Everything appears an orange colour, though the rocks themselves are really grey. Maybe there will be valuable minerals on Venus, which may come in handy when we have used up all the metals on Earth, but it would be very difficult to mine them in the terrible conditions there. So let’s move on closer still to the Sun, to Mercury.

* Careful! It is not twice as hot as your oven though the temperature is double, because the absolute zero of temperature is –273º C.
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Crescent Venus
Venus seen from Earth
Credit Damian Peach

Venus from space
Venus from space

Radar view of Maat Mons on Venus
Radar view of Maat Mons on Venus