ENVIRONMENTS ON OTHER WORLDS

MARS

Despite its apparent similarity to deserts on Earth, Mars is different from any environment on this planet. Yes, it’s dry, but that is because the planet’s atmosphere has been largely stripped away, along with its water vapour. Mars also has much less gravity than Earth – you’d weigh about one-third of what you do here. Even in the driest desert on Earth, rocks are still heavier than on Mars!

EUROPA AND ENCELADUS

These two small moons of Jupiter and Saturn are thought to have vast underground oceans under their thick ice surfaces. Dark, cold and salty, with very high pressures, could the deep sea trenches of oceans on Earth give us a clue of the environments on these moons? Astrobiologists see these moons as one of the top priorities in the search for alien life.

VENUS

Although the surface of Venus is hot (450°C), high up in the atmosphere the temperature and pressure is similar to that of the Earth. Only one problem: the clouds are made of concentrated sulphuric acid. Weird bacteria are known to exist in highly acidic water on Earth, such as in Ethiopia’s Dallol pools. But the acid clouds on Venus are more than 1,000 billion times more acidic than Dallol!

TRAPPIST-1E

Orbiting a star 40 light-years away, this may be the planet most similar to Earth that we have discovered so far. There may even be liquid water on the surface. But we won’t know more about it until new space telescopes are launched next year to look for signs of life outside the Solar System.

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