Mars - the Red Planet

Because Mars is so near Earth, people could see it thousands of years before there were telescopes. The Babylonians (who lived three to five thousand years ago in modern Iraq), the Greeks and the Romans saw this red planet and they thought it was angry. That made them think of war and men (who are more often angry than women). So, these ancient people gave the name ‘Mars’ to their god of war. They had a special sign for Mars too. Maybe you know it. It’s ♂, the same sign we use in biology for ‘male’.

There is not much more to say about our understanding of Mars until two or three thousand years later in sixteenth century Europe. Tycho Brahe, a Danish astronomer and aristocrat, was the last scientist to look carefully at the sky without a telescope. Brahe was a strange man. He had a nose made of gold and silver because he lost his in a sword fight. He also had a pet elk which died when it fell down the stairs drunk after too much beer at dinner one night. Brahe was a very polite man. He died because he needed to go to the toilet but was eating dinner with the King and thought it would be rude to go to the bathroom. So, he waited and waited until he became ill.

Although he was odd, Brahe was very rich and very interested in science – he made many natural medicines that people in Denmark used centuries after his death – and he studied Mars for twenty years. He made scientific instruments to study the planets and stars. But Brahe thought that the planets went around the sun and the sun went around the Earth. One of his assistants was Johannes Kepler, the great German astronomer, who showed that the planets went around the sun in ellipses, not circles. Kepler used Brahe’s careful notes from many long nights looking at the sky to arrive at his ideas, as well as Galileo’s theory that the Earth was not the centre of the universe.

In the same way that Brahe saw that Kepler was a great astronomer and helped him, Kepler very quickly understood Galileo’s importance. Of course, Galileo had a telescope – something that Brahe did not have. Although it was not very good – it made things only six times bigger than we can see them with our own eyes – it changed astronomy for ever. Galileo saw that Mars had dark areas on it and was not all orange-coloured.

More than three centuries later, Giovanni Schiaparelli, an Italian astronomer, had a 22 cm telescope. In 1877, he made a map of Mars with canals on it, although there was no water in them. This made Schiaparelli think that people lived on Mars long ago. He believed that they made the canals to take water to their fields, but now there was no water they were probably all dead. This was very exciting news and many writers – like H. G. Wells, who wrote ‘The War of the Worlds’ and other science fiction books – started to write about life on other planets. Forty years later, in 1909, Camille Flammarion, a French astronomer looked at Mars with a much bigger telescope than Schiaparelli’s – it was 84 cm from one side to the other – and could not see the canals. But the popular idea that there was life on Mars never died.

Now we know that Mars is one of the nearest planets to ours. It is about 75 million km away and we can get there in about a year. This may seem a long way but it’s like our garden or the street outside our flat if we compare it to Jupiter, Saturn or Pluto. We also know that it has got freezing cold deserts, volcanoes and very strong winds. There’s also polar ice that gets bigger and smaller at different times of the year.

Mars looks like it changes colour but this is only because storms send dust into the air. Actually, the planet is red. The colour comes from rusty iron. The atmosphere is only 1% of ours and 96% of the air is carbon dioxide (CO²). This makes it very hard to land spaceships on Mars because they travel at 12,000 km per hour and cannot slow down because there is no atmosphere.

In the 1970s, we thought it was very dry and had no life on it but, in 2005, we discovered ice just under the surface of the planet. We also know that there are five elements that make life and four of these seem to be everywhere in the universe: carbon (C), oxygen (O), hydrogen (H) and nitrogen (N). We don’t think the same way about life nowadays as we did in the 1970s either. That’s not because of what we have learnt about space, but what we know about our planet.

For instance, we thought that there could be no life in the deepest parts of the Pacific and Atlantic Oceans. But there is. We were sure that life could not exist in the Arctic – but we now know there are bacteria there. This makes us think that, maybe – just maybe – there could be life in other difficult climates and atmospheres, like Mars.

When we want to look carefully at a planet, there are four steps or stages. First, spaceships fly near it and take photos. We did this with Mars in 1965. (Of course, these are only ships. There are no people on them.) If the photos are interesting, we try to put a spaceship in orbit around a planet so that it goes round and round and we can get a longer look. Third, we try to get samples – bits of rock, for instance. Finally, we try to visit it.

The third stage is where we are now with discovering more about Mars, but there are problems. It may be dangerous to bring bits of Mars to Earth. We don’t know if we will get sick from them or what will happen. People say that meteorites from Mars have hit Earth before. In fact, we have about thirty-five meteorites from there. But they came from the surface of the planet where we know that nothing lives and were millions of years in space, which is sterile – it has no bacteria or viruses, nothing. They came from the surface and we are especially interested in the inside because that’s where water, carbon and, so, life may be.

In 2002, the US space project, Beagle 2, tried to find life – now and in the past – and carbon on Mars. The problem was that it landed in a storm and we do not know where it is now. Beagle was going to look under the surface of the planet to see if there was carbon and ice.

These days we use the Moon as a testing place and hope that we can use the information we get there on Mars later. After all, Mars is the only planet which we can visit in the next century or two. But there is no chance that we can find Martians like H. G. Wells imagined.