If we move outwards away from the Earth we will eventually encounter a planet which has been the focus of interest, mystery and on occasion, fear. It is Mars, the Red Planet. Named after the Roman god of war, Mars justly earns its descriptive title of red planet. If you look at it with the naked eye or even better, with binoculars, you may see that it indeed has a reddish colour to it.
The aspect that has been the reason to hold our attention and imagination for so long is that it is a planet which could support life. There is however, a big difference between the beings that were thought to live on the planet when Mars was first studied with telescopes and the type of life we may find there in the near future.
The idea that intelligent life existed on Mars came via a simple mistake in translation. It was the astronomer Schrapelli in the 19th Century who observed a number of distinctive lines or rips in the surface of Mars. He termed these features “channels” and recorded them as such. However, the problem arose when it came to translating the Italian word for channels. It came out wrongly as canals. Further investigation showed that these “canals” were now dried up and no signs of life could be detected.
But this did not halt the speculation. People now began to believe that the Martians now lived underground where they could seek protection from the harsh conditions on the surface. Things took an even bigger step into unreality when in the 1930s a radio play was broadcast in the United States of America. It was “The War of the Worlds” by H.G. Wells. The programme included a radio news broadcast within the story which said that Martians had landed and invaded the Earth. Rumours spread like wildfire and very soon a large part of the nation panicked and began to flee their homes. This may be hard to accept in this day of mass communication but it did happen.
But enough of the fiction attached to Mars. The canals of Mars were found to be a system of long cracks and canyons on the surface. They stretch for about 2,500 miles near to the planet’s equator and are called the Valles Marineris. They were formed about 3.5 billion years ago by geological forces. There is however a link to canals because it is now believed that in the past these canyons carried water. In fact we understand that water erosion played a part in the formation of these features.
Water in its liquid form no longer exists on the surface of Mars. But Mars does have polar caps composed of water ice. With a temperature range of between -120ºC to +20ºC, we can observe the ice caps receding and growing as Mars moves through its seasons. The large temperature range is due to the fact that Mars has quite an elliptical orbit around the Sun. This means that the distance from the Sun can alter by about 26 million miles during its year. Incidentally, a Martian year is a little under two Earth years but its day is almost the same as ours at approximately 24 hours.
Mars is smaller than the Earth at 4,220 miles. It has a small iron core surrounded by a mantle composed of silicate rock. The crust is made of rock. Its reddish colour comes from the iron oxide, better known as rust, on the surface. Mars used to be volcanic and much of the northern hemisphere is made up of solid lava plains. The southern hemisphere is more mountainous and is pockmarked with craters. Mars has one special claim to fame; as far as we know, it contains the biggest volcano in the solar system. It is called Olympus Mons and is 15 miles high.
The atmosphere around Mars is very thin and consists mainly of carbon dioxide with small amounts of oxygen, carbon monoxide and trace gases. There are some thin clouds present which are made up of frozen carbon dioxide and water ice. The oxygen level is far too small to support life and the carbon dioxide is poisonous to humans at these levels.
Mars has two natural satellites or moons in orbit around it. They are called Phobos and Deimos. In keeping with the rather violent name that Mars represents, these moons also have war-like meanings; Phobos means fear and Deimos translates into dread. As was discussed in the previous blog article, our moon is large in comparison with the Earth. But in Mars’ case, the opposite is true. Both of its moons are relatively tiny. Phobos is only about 16.5 miles across and Deimos is even smaller at just over 9 miles.
They also orbit very close to their parent planet. Phobos is the inner moon and orbits Mars every 7 hours and 39 minutes. Compared with Mars’ day lasting for about 24 hours, it means that Phobos rises and sets up to 3 times a day. Deimos is a bit further out and orbits the planet in 30 hours and 18 minutes. Both of them orbit in the equatorial plane of the planet. In fact both of them should not strictly be called moons; they just don’t match up. They are both more likely to be passing asteroids which were caught by Mars’ gravity and have remained captured in orbit since.
Mars is currently the focus of a number of orbital probes and vehicles on the surface. The latest also includes the first helicopter ever to be used on another world. These latest vehicles will also be searching for primitive forms of life and will include drilling into the Martian soil in its search. All of these endeavours are in preparation for the first human expedition to the planet. Currently NASA is aiming at 2035 but the commercial space companies like Space-X have other ideas. They have plans to reach there much earlier. So watch this space. And yes, the pun was intentional.
John Pullen 