Mars is the fourth planet from the sun and second smallest planet in the solar system. The red Planet is at an average distance of 142 million miles (1.52 AU) from the sun. It is a cold desert world having seasons, Polar ice cap and weather and canyons and extinct volcanoes like earth.
It has very thin atmosphere made of carbon dioxide, nitrogen and argon.
Day and Year
The solar days on mars is 24 hours 39 minutes, slightly longer than earth day.it takes 687 earth days to orbit around sun i.e. A Martian year is equal to 1.8809 earth year.
Mars’s axis of rotation is similar with earth. It has Axial tilt 25o relative to orbital plane. It has distinct session like earth, though on Mars they are nearly twice as long because its orbital period is that much longer.
Surface and Structure
Red planet is terrestrial planet like earth. Its surface consists of minerals containing silicon, oxygen, Metals and other elements that typically make up rock. Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium, and chlorine. It surface looks reddish due to oxidization/rusting of iron in the rocks, Martian soil, and dust.
Mars is half of the diameter of the Earth having volcanoes, mountains, canyons, and craters. It carry the largest volcano “Olympus Mons” in the solar system. This volcano is three times taller than the Mount Everest.
The large canyon “Valles Marineris” has a length of 4,000 kilometres and a depth of up to 7 kilometres. The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. It is about 10 times the size of the earth’s Garand canyon.
Mars has two permanent polar ice caps consist primarily (70%) of water ice. The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 metres. But Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% that of the Earth’s.
Like the earth, Mars has dense metallic core at centre with radius of 1500 km to 2100 km, consisting primarily of iron, Nickel, and sulfur. The core is surrounded by a silicate Mantle that formed many of the tectonic and volcanic features on the planet and it is about 1240 km to 1880 km thick. Above the Mantle a Crust made of iron, Magnesium, Aluminium, calcium, and potassium. The crust is 6 km to 50 km thick.
Size and Distance
The mean diameter of mars is 6779km approx half of the earth’s diameter (0.532 De). It is located an Average distance of 1.52 Astronomical unit from the sun. At this distance light will take 13 minutes to travel from the sun to Mars.
Its mass is 0.107 times the earth’s mass i.e. 6.4171×1023.
The atmosphere of mars is very thin consists about 96% carbon dioxide, 1.93% Argon, 1.895 nitrogen along with traces of water and oxygen and it does not offer much protection from the asteroids, Meteoroids, and comets impact. The atmosphere is quite dusty, containing particulates about 1.5 µm in diameter which give the Martian sky a red colour when see from the surface.
Atmospheric pressure on surface varies from 30 Pa on Olympus Mons to 1155 Pa in Hellas Planitia, with a mean pressure at the surface level of 600 Pa, 0.6% of that of Earth (101.3 kPa).
Mars’s session is similar to the Earth due to same axial tilt of these two planets, but the lengths of the Martian seasons are about twice those of Earth’s because Mars’s greater distance from the Sun leads to the Martian year being about two Earth years long. Martian surface temperature varies from -143oC at winter polar caps to 35oC at equatorial summer with mean surface temperature is -63oc (210K).
Mars has strong dust storm in the solar system with velocity of about 160 Km/h, which is strong enough to cover entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.
Orbital and escape velocity
Mars’s average orbital speed is 24.007 km/s (0.8 times the earth’s avg. orbital speed) and its escape velocity is 5.027 km/s (0.45 earth’s escape velocity).
Mars does not have a global magnetic field which guides charged particles entering the atmosphere. It has multiple umbrella-shaped magnetic fields mainly in the southern hemisphere, which are remnants of a global field that decayed 4 billions of years ago, possibly because of numerous asteroid strikes on its surface.
Surface gravity is only 3.72m/s2 (0.3794 earth’s surface gravity).
Mars has potato shaped two natural moons namely Phobos and Deimos. Phobos is about 221 km wide and Deimos is just 12km Wide.
Both moons were discovered in 1877 by Asaph Hall; they are named after Greek god of war Ares.
Phobos is the innermost moon to the Mars, rises in the west, sets in the east, and rises again in just 11 hours. Because the orbit of Phobos is below synchronous altitude, the tidal forces from the planet, Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars’s surface or break up into a ring structure around the planet.
Deimos is the outer moon to the Mars, rises in the east but slowly. Despite the 30-hour orbit of Deimos, 2.7 days elapse between its rise and set for an equatorial observer, as it slowly falls behind the rotation of Mars.
Mars has no ring, but in future Phobos break up into small pieces and form ring around planet.
Due to lack of a magnetosphere and the extremely thin atmosphere; Mars has little heat transfer across its surface, poor insulation against bombardment of the solar wind and insufficient atmospheric pressure to retain water in a liquid form makes difficult for life on Mars. But recent abidance suggests the sign of life on Mars, when its surface is warm and covered with water.
Dozens of crewless spacecraft including orbiters, landers, and rovers have been sent to Mars by the Soviet Union, the United States, Europe, and India to study the planet’s surface, climate, and geology.
As of 2018 six spacecraft are in orbit of Mars and two rovers on its Surface. Out of six spacecraft; Mars Reconnaissance orbiter, Mars odyssey, and Maven spacecraft are managed by NASA. ESA managed the ExoMars Trace gas Orbiter and Mars express Missions. In 2014 India 1st Red planet spacecraft Mars Orbital mission (MOM) launched by ISRO.
In August 2012 NASA’s Curiosity reached on Mars surface to exploring Mount Sharp in Gale Crater. On 10 February 2013, the Curiosity rover obtained the first deep rock samples ever taken from another planetary body, using its on-board drill.
In November 2018 NASA’s InSight a stationary lander reached on Mars surface and it detected first potential mars quake in April 2019.
Now NASA is launching Perseverance Rover on 21 July – 11 Aug 2020 and it is expected to land on mars surface 18 Feb 2021. This mission provides opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars.
In Roman mythology Mars is the god of war, murder, and bloodshed. Mars is the son of Juno and Jupiter and father of Romulus and Remus. In Hindu mythology Mars is known as Mangala. His origins vary with different mythological texts; in some, he is the son of Bhumi; the Earth Goddess and Vishnu, born when he raised her from the depths of water in Varaha avatar. In other myths, he is born from Shiva’s sweat or blood drop.
Quick Discover :
Distance from the sun:
1.52 Astronomical unit
Average orbital speed:
Equatorial rotational velocity:
687 Earth days
24 hours 39 min.
Potential for Life:
Image credit :
Image8:NASA/JPL-Caltech/University of Arizona
Image9: NASA/JPL-caltech/University of Arizona