Mars, (The Bringer of War) is known as the 'Red Planet', because of its distinctive red appearance from Space. It has also featured in many theories involving alien civilizations - there have been stories about it being the home of a hostile civilization, the base of an advanced species of human and even the home of a dying civilization! Many astromoners, such as Percival Lowall, claimed that its 'canal-like' markings indicated that an advanced alien species lived there. In 1964 however, the Mariner 4 probe - to the disappointment of many people - confirmed that at present, there are no signs of an advanced civilizations but that there are dried up riverbeds which means that there was once water on Mars which in turn means it was actually capable of supporting life once.

    Often, Mars is depicted as being very similar to Earth's moon - a small dust-covered lifeless body, cold, dry and inhospitable. However, as our knowledge of this planet has increased (very rapidly) over the past few decades, as Mars has become the most visited and most known about planet, this notion has long since been shattered, and has been replaced with one of a complex, intriguing planet, with many exciting secrets yet to be revealed. The simple, desert-like images beamed back by various landers on Mars are merely a false façarde, for an interesting world, which certainly has aroused a lot of interest in the past few years in particular. There's a lot more to Mars than dust.

Dust Covered Planet

    One of the ways in which Mars has been able to deceive people into believing it to be a fairly dull, uninsteresting world is by being covered by dust. This is the most initially striking feature about Mars. In fact, this very fine-grained material, settled out of the atmosphere, is present throughout Mars, and forms a thick layer even on the highest volcanoes. The dustier areas of Mars are those which appear most bright.

    As this dust settles on Mars, it can trap volatile materials, forming a mantle of icy dust. After some time, these volatile ices can turn to dust, leaving strange pits. This icy mantle, whose thickness varies throughout Mars (it is thickest at the poles) is increasingly becoming the subject of scientific investigations. Evidence suggests that this mantle may once even have flowed like a fluid, thus bearing some resemblances to a glacier here on Earth.

Windy Weather, Climate and Atmosphere

    Although it may at first appear rather strange for a cloudless planet, wind is actually a major characteristic of Mars, and it is this wind which has shaped the Martian landscape into what we see today. Spacecraft visiting the planet have witnessed dust storms and avalanches, both seemingly caused by wind. In fact, dust patterns behind some large objects can be observed to change according over time, due to the varying wind conditions, and sand dunes can be observed to move, due to dust deposition. Evidence of erosion too can be found in craters.

    Although Mars is smaller than the Earth, its much slower spin means that a Martian day lasts only 41 minutes longer. In addition, Mars has a similar axial tilt as we do, so a Martian year is made up of four distinct seasons. The years themselves however are 687 days long, so each season would last 6 of our months. Even though Mars' atmospheric pressure is less than 1% that of the Earth's, it has a considerable impact on Mars, and it can vary seasonally by up to 25%. Despite being thin, the presence of dust and ice particles in the atmosphere give it some complex dynamics, which go some way towards explaining why Martian weather does contain such strong winds, in addition to variable low level fogs, seasonal frost, high-level ice clouds and even dust storms.

Is There Water on Mars?

    A distinct physical feature of Mars is the presence of the two polar ice caps. Scientists have deduced that these are composed mainly of water ice. Recent discoveries have included discovering water ice below the Martian surface, present for most if not all of the Martian year. In fact, Mars Odyssey detected the presence of ground ice over most of the planet, apart form the equatorial regions. However, despite this, significant amounts of water in liquid form are not present on Mars, and have not been for a very long time.

The Changing Face of Mars

    Recent evidence however has showed that the Southern ice cap is being eroded at a relatively high rate, prompting many theories about why this may be. It is thought that the Martian climate and weather is actually changing over time.

    Indeed, there is evidence to suggest that Mars has changed significantly over time. For instance there's the fact that the Southern hemisphere is high and heavily cratered, whereas the Northern hemisphere is both lower and flatter, a sign that it is younger. In addition, certain features along the edge of the Southern highlands bear characteristics which could only have been formed by liquid water. So whilst today Mars may look more similar to the Moon than the Earth, there is evidence to suggest that this may not have always been the case.

Volcanoes and Valleys

    Mars also has the largest volcanic mountain in the Solar system - Olympus Mons, which is 27 kilometres high and 600 km across! Not only that but it has a collection of Volcanoes in the north that are so big that they deformed the planet's spherity. It also has large spaces going down - the Vallis Marineris canyon system stretches for over 5,000 kilometres and is up to 7km deep - it's the dark patch you can can see to the right on the picture above.

Moons

Mars has two natural satellites - Phobos (meaning fear) which orbits at just 5982km and Deimos (meaning terror) which orbits at 23,000km and looks like a bright star from the Martian sky. Because of their size and irregular shapes, scientists believe they are captured asteroids. To find out more about them, look at our Phobos & Deimos section.

More info on Phobos and Deimos

    Mars has been looked up to for centuries and as I mentioned earlier, there have been many theories about it. It's only recently however that we've been getting better, more close-up pictures. The first close-up surface pictures were made in 1964/5 by the Mariner 4. More high-resolution pictures followed form Mariners 6 and 7 but it wasn't until 1971 and Mariner 9 that detailed photos of Phobos and Deimos were taken. In the same year the Soviet Mars 2 dropped the first capsule on Mars. Then in 1975 the Viking landers arrived at the moon taking photographs from the surface. Then there was a big gap until December 1996, when the NASA Mars pathfinder landed on Mars. This was basically a robot which was controlled from Earth and which explored Mars and conducted experiments, making many new discoveries. The Pathfinder was followed by the NASA Mars Polar lander in 1999 and I think it's fair to say that it was a big flop. It was meant to be a mission to search for water on Mars but in the end radio signals were lost with the MPL. There are more missions planned for the future though, including the very promising and exciting 'Mars Express' from ESA.