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All about Mars

Is there life on Mars?

Scientists conclude from the many visible channels, looking like dried-up river beds, that liquid water probably ran across the surface of Mars around 4 billion years ago. And as we all know, without water, life as we know it cannot exist. But nowadays, it is so cold that most of the water may be locked into frozen layers deep in the soil. Recent missions to Mars have discovered hydrogen-rich layers under the Martian surface, indicating the presence of water ice around the planet’s south pole.

The Mars Express mission, due for launch in May/June 2003, has the tools to search for signs of life both past and present and to search for evidence of water a few kilometres below the surface, giving a global picture of where the water is and its depth.

 

The fourth planet from the Sun is famously red, but what else do we know about it?

Named after the Roman god of war, Mars can easily be seen with the naked eye, especially when its orbit brings it closest to Earth, which is roughly every 26 months. However, you might have difficulty spotting the tiny Martian moons, which are two of the darkest objects in the Solar System. Called Phobos and Deimos, they are thought to be asteroids caught up in Mars’s gravity.

Mars itself is about half the size of Earth. Its fabulous orange-red colour is a result of its soil, which is rich in iron oxide, commonly known as rust. The surface may resemble a barren wasteland, but Mars is also home to some of the most dramatic landscapes in the Solar System. It certainly has the largest volcano, Olympus Mons, rising 24,000 m above the surface – that’s three times the height of Mount Everest – and 550 km in diameter.

Mars has an enormous set of canyons called the Valles Marineris, which dwarfs the Grand Canyon. These canyons represent about a fifth of the Martian circumference: they are 4,000 km long and can get as deep as 7 km, while the Grand Canyon is only 450 km long and 1.6 km deep. There are also countless impact craters on the surface of Mars.

The breathtaking scenery is thanks to Mars’s turbulent history. Around 3.8 billion years ago it was subject to a brutal bombardment by meteorites. Volcanic eruptions that could have poured out molten rock for millions of years at a time also marked the surface of Mars.

The weather is not too good, either. During a Martian storm, windspeeds can reach 300 km/h, stirring up dust that can smother the whole planet. Temperatures can drop as low as -133°C, although during the Martian summer, they reach a pleasant 27°C.

But don’t let the top temperatures fool you into considering Mars for a holiday. The atmosphere, one hundred times thinner than Earth’s, is mainly carbon dioxide, and solar winds are constantly blowing more of this atmosphere away. Then there’s the pressure – at the surface it’s just one per cent of Earth’s. This combination of thin atmosphere and low pressure means that even if you took some liquid water to Mars, it would either freeze or boil the instant you stepped out of your spacecraft, depending on the local temperature and pressure.

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