Mars

The Planet Mars was named after the Romans after their god of war because of its red, bloodlike colour. Other civilizations also named this planet from this attribute; for example, the Egyptians named it ‘Her Desher,’ meaning ‘the red one.’

Known as the ‘Red Planet’, Mars can be easily identified by its reddish glow. The probes by Viking I and II have revealed it to be a barren, desolate desert with mainly a layer of orange red material over the darker bedrock. Strong winds lift up clouds of the fine dusts of the surface and fill the atmosphere with a reddish haze, which account for the colour of the planet. This reddish colour of the dust may be attributed to a thin coat of iron oxide or some completely different material.

Mars is the fourth planet from the Sun. It is smaller than the Earth, and has a very thin atmosphere, having mostly (95%) carbon dioxide, along with faint traces of oxygen, nitrogen and water vapour. Since it is further away from the Sun than the Earth, it is much colder too. Mars does not have a protective layer of atmosphere like the Earth, so it cannot store heat from the sun. As a result, the temperature on Mars regularly drops to -82ºC in the winter and only rises to - 5º C in the summer.

Due to the prevailing cold temperatures and thin atmosphere of Mars, liquid water cannot exist on its surface for long. It was revealed in early telescopic observations that. Mars has permanent ice caps at both of its poles..Now it is confirmed that those ice caps are composed of water ice and solid carbon dioxide.

Mars takes 24 hours and 37 minutes to rotate on its tilted axis and 687 days to complete one revolution. It experiences seasons due to the tilt of its rotational axis. Mars' orbit is slightly elliptical, so its distance from the sun changes. That affects the length of its seasons, which vary in length. The polar ice caps on Mars grow and recede with the

seasons. They exhibit a layered structure with alternating layers of ice with varying concentrations of dark dust. The layered structure of the Martian snow caps suggests a change of climate of the planet for more than once. It is also believed that, more than 3 billion years ago, volcanic activities were prevalent in the highlands and plains of Mars.

With Olympus Mons, as well as Valles Marineris, Mars has the largest volcanoes in the solar system.

Interestingly, Hydrogen-rich polar deposits, indicating large quantities of water ice close to the surface of Mars, were detected by NASA's ‘Mars Odyssey’, in 2002. Further observations also found hydrogen in other areas as well. Mars could have substantial subsurface layers of frozen water, if water ice permeated the entire planet. Structures and minerals, indicating that liquid water once existed at its landing site, was further detected in 2004, by Mars Exploration Rover ‘Opportunity’. The signature of ancient water near its landing site, halfway around Mars from Opportunity's location, was also detected by the Rover's twin, ‘Spirit’. The process of research regarding Martian rocks and soil at Gale Crater, is now in progress. NASA's Mars Science Laboratory mission, with its large rover, is looking for minerals that formed in water, signs of subsurface water, and carbon-based molecules called organics, the chemical building blocks of life. The resulting information will reveal more about the present and past habitability of Mars, as well as, the most important information, whether humans could survive on Mars some day.

As Mars has about one-third the gravity of Earth, everything weighs less on Mars than they weigh on Earth. Mars has no global magnetic field today. But, NASA's ‘Mars Global Surveyor Orbiter’ found that, areas of the Martian crust in the southern hemisphere are highly magnetized, which are the remnants of an ancient global magnetic field in Mars 4 billion years ago.

The two moons of Mars were discovered in 1877, by American astronomer Asaph Hall and he named them Phobos (meaning fear) and Deimos (means rout), the sons of Ares, the Greek counterpart of the Roman war god, Mars. It remains uncertain how they were born. Probably, once they were asteroids and subsequently they were captured by Mars' gravitational pull, or they may have been formed in orbit around Mars the same time the planet came into existence. Both of them are apparently made of carbon-rich rock mixed with ice and are covered in dust and loose rocks. They have very little mass and almost negligible gravitational pull.