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10 Facts to Know About Planet Mars

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The Red Planet: actually chilly cold

The Red Planet: actually chilly cold

1. The Red Planet Is Chilly Cold

Mars is sometimes also called the Red Planet because of its orange-red appearance. Yet its color is misleading, as Mars actually is chilly cold, the average temperature being around -55°C (-67°F), with extreme lows of -143°C (-225°F) at the winter polar caps. The red color instead is due to the large amount of iron-rich dust that covers the Martian rocks and soil.

2. The Tallest Mountain in the Solar System

Mount Everest is the tallest peak on Earth, but it pales in comparison to Mars' Mount Olympus: with a height of 22 km (13.6 mi), Olympus Mons stands about two and a half times taller than Everest.

Olympus Mons resembles the large shield volcanoes making up the Hawaiian Islands but is more than twice times taller than Mauna Kea (measured from its ocean floor base, Mauna Kea is the tallest mountain in the world with a height of 10,200 m (33,465 ft). The base area of Mount Olympus is so large it would almost cover France.

Olympus Mons dwarfs Mount Everest

Olympus Mons dwarfs Mount Everest

3. Mars Is Home to Gigantic Canyons

The Grand Canyon of Arizona is surely a spectacular sight, but it is miniature compared to Mars' Valles Marineris: 4,000 km (2,500 mi) long, 200 km (120 mi) wide, and up to 7,000 m (23,000 ft) deep! It is easily recognizable on Mars images and got its name from the Mariner 9 orbiter that discovered it.

Valles Marineris: Grand Canyon XXL size

Valles Marineris: Grand Canyon XXL size

4. The Martian Year Lasts 687 Days

If you’re short on time, Mars is for you: the Martian year lasts a whopping 687 days. That's how long it takes the Red Planet to circle around the sun.

The Martian solar day (sol) on the other hand, is only slightly longer than a day on planet Earth: 24 hours 39 minutes and 35 seconds.

5. Mars Has Seasons

Of all the planets in our solar system, Mars is the most Earth-like. This is due to the similar tilt of the rotational axis of the two planets: 25.19 degrees for Mars, compared to 23.44 degrees for Earth.

Yet, winter and summer on Mars are almost twice as long because of the Red Planet's longer orbital period. Overall, the temperatures on Mars vary widely due to its thin atmosphere and the larger eccentricity of the Martian orbit.

6. Mars Has Two Moons

The two planets closest to the sun, Mercury and Venus, have no moon. The third, Earth, has one while Mars as the fourth planet from the sun has two natural satellites: Phobos and Deimos. Yet they are much smaller, even compared to the minor size of their planet, and less round than the Earth’s moon.

Closest to Mars is Phobos with a diameter of about 22 km (14 mi) and an 11-hour orbit, followed by Deimos with a diameter of about 12 km (7.5 mi) and a 30-hour orbit.

Phobos is so close to its primary body that it orbits Mars faster than Mars rotates. As a result, from the surface of Mars, it appears to rise in the west and set in the east, moving across the sky twice on each Martian day.

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Phobos: not the roundness earthlings are used to

Phobos: not the roundness earthlings are used to

7. Named After the Roman God of War

Mars can be seen with the naked eye and has therefore been observed since ancient times. Former cultures like the Sumerians and the Indians saw it as a portent of war and death. When the Romans came around they named this furious red celestial body after their god of war: Mars.

Mars and Aphrodite (Venus)

Mars and Aphrodite (Venus)

8. Unmanned Mars Landings

So far, manned spaceflight has not ventured beyond the moon, but there have already been a number of successful robotic Mars landings.

The first successful touchdown on the surface of the Red Planet was by NASA's stationary Viking 1 lander in 1976. Two decades on, in 1997, followed the first mobile probe: the rover Sojourner of the Mars Pathfinder mission, although contact was lost after just a couple of months.

The Mars exploration rover Spirit was next, landing successfully in 2004 and remaining operational until 2010. During its 6 year mission, it drove 7.7 km (4.8 mi) on Martian soil. Opportunity did even better, as it landed in 2004 and remained operational for 14 years, traveling some 45 km (28 mi).

Over time, the size of the rovers continuously increased. Curiosity landed in 2012, weighs 899 kg (1,982 lb) and already has the size of a car.

The latest and most sophisticated is the Mars 2020 Perseverance, Rover which was launched in July 2020 and is expected to land on Martian soil in February 2021.

Three generations of Mars rovers at NASA's Mars Yard testing area

Three generations of Mars rovers at NASA's Mars Yard testing area

9. No Green Man Around

Popular culture once imagined little green men with antenna living on Mars. None of the camera-equipped rovers that landed so far managed to get a shot of any of these.

In reality, the Martian environment is extremely hostile to life as we know it. Located at the very outer edge of the habitable zone and having an extremely thin atmosphere, water, the most basic element of life, cannot exist on Mars in its liquid form (except for a very short time in limited areas).

10. Man on Mars as the Next Big Step in Space Exploration

Almost half a century has passed since man last walked on the moon (1972). No really big advancement in space exploration has been made since then. As the surface of Venus is totally unsuitable for a landing due to its high temperature and atmospheric pressure, a manned Mars landing will undoubtedly be the next huge step forward in the exploration of space.


  • The Case for Mars, by Robert Zubrin and Arthur C. Clarke
  • The Stargazer's Guide to the Night Sky, by Jason Lisle

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2016 Marco Pompili

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