The following is a comparison between Earth and Mars, the third and fourth planets from the sun, respectively.
Earth and Mars – a comparison
Earth vs Mars – size comparison
Earth is the fifth largest planet in the solar system. Among the terrestrial planets (Mercury, Venus, Earth, and Mars), it is the largest. Mars is the second smallest planet in the solar system after Mercury.
Earth diameter – 12,742 km (7917.5 miles)
Mars diameter – 6,779 km (4,212 miles)
Moons
Earth has one moon, which is one of the largest natural satellites in the solar system. Mars has two small, irregular-shaped moons, Phobos and Deimos.
Gravity on Earth vs Mars
If an object weighs 100 N on Earth, it will weigh about 38 N on Mars. The weight of an object on Mars is about 38% of its weight on Earth.
Acceleration due to gravity on Earth = 9.81 m/s²
Acceleration due to gravity on Mars = 3.73 m/s²
Atmosphere
The atmosphere on Mars is very thin. The atmospheric pressure is generally between 6 and 7 millibars. The atmospheric pressure on Earth is 1.013 bar.
Earth atmosphere composition (main)
Nitrogen – 78.08%, Oxygen – 20.95%, Argon – 0.93%, Carbon Dioxide – 0.04%
Mars atmosphere composition (main)
Carbon Dioxide – 95%, Nitrogen – 2.6%, Argon – 1.9%, Oxygen – 0.16%
Ice caps
Both Earth and Mars have polar ice. The top of polar ice caps on Mars is made of carbon dioxide ice which forms during fall and winter and disappears during summer. Under the carbon dioxide ice lies the stable water ice.
Temperature
Mars is a relatively colder planet. The average temperature on Mars is -65°C (-85°F). The average temperature on Earth is about 15°C (59°F).
Axial tilt
Both of these planets have similar axial tilts. Earth’s rotational axis is tilted at an angle of about 23.5 degrees with respect to a perpendicular to the orbital plane. Mars’ axis is tilted at an angle of about 25 degrees.
Day and year
Due to similar axial tilts, Earth and Mars have almost equal day lengths.
1 day on Earth = around 24 hours
1 day on Mars = around 24.6 hours
1 year on Mars is almost equal to 1.9 Earth years.
1 year on Earth = 365 days
1 year on Mars = 687 Earth days
Mars is located near the outer boundary of the habitable zone
The habitable zone is a region in a solar system where liquid water can exist on a planet’s surface given the atmospheric conditions are right. Mars is located near the outer boundary of our solar system’s habitable zone. Earth is well within the habitable zone.
Highest mountain
The highest mountain on Mars is Olympus Mons. It is 21.9 km (13.6 mi) high. This means that Olympus Mons is almost 2.5 times as high as Mount Everest (8,848.86 m).
Surface area
Mars has a total surface area of about 145 million square km. The open land on Mars and Earth is about the same as 71 percent of Earth’s surface is water.
