Mars, known as the "red planet" because of its distinctive reddish color, is the fourth planet from the Sun in our solar system. This characteristic color comes from the presence of iron oxides on its surface.
Mars has sparked great interest among both scientists and the general public due to its similarities and differences with Earth, as well as the possibility of past or future life.
Besides Earth, Mars is the planet most likely to have hosted life in the past. Evidence such as ancient river beds, hydrated minerals, and the presence of liquid water in the past suggests that Mars had habitable environments billions of years ago.
General characteristics
Mars has a diameter of about 6,779 kilometers, a little more than half the size of Earth. Its mass is only 10% of the Earth's mass, resulting in a surface gravity of approximately 38% of that of Earth. This means that a person weighing 100 kg on Earth would weigh only 38 kg on Mars.
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Position in the Solar System |
Fourth planet from the Sun |
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Diameter |
Approximately 6,779 km |
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Time |
6.42 × 10^23 kg (10% of Earth's mass) |
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Gravity |
3.71 m/s² (38% of Earth's gravity) |
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Day length (Sun) |
24.6 hours |
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Length of the year |
687 Earth days |
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Axial tilt |
25.2 degrees (similar to 23.5 degrees on Earth) |
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Medium temperature |
-63°C (variations from -125°C at the poles to 20°C at the equator) |
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Atmosphere |
Composed mainly of carbon dioxide (95.3%), nitrogen (2.7%) and argon (1.6%) |
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Atmospheric pressure |
Less than 1% of the Earth's atmospheric pressure at sea level |
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Surface |
Characterized by volcanic plains, mountains, valleys, craters, and polar ice caps |
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Natural satellites |
Two small moons: Phobos and Deimos |
Atmosphere and climate
Mars' atmosphere is much thinner than Earth's, composed primarily of carbon dioxide (95.3%), with small amounts of nitrogen (2.7%) and argon (1.6%).
The atmospheric pressure on the surface of Mars is less than 1% of the atmospheric pressure on Earth at sea level.
Due to its thin atmosphere and distance from the Sun, temperatures on Mars are extreme, with an average range from -63 to -125 degrees Celsius at the poles during winter to 20 degrees Celsius at the equator during summer.
Surface and geology
The surface of Mars is a mix of flat plains, giant mountains and deep valleys.
One of its most notable features is Olympus Mons, the largest volcano in the solar system, rising 22 kilometers above the Martian surface. Another important feature is Valles Marineris, a canyon system that extends for more than 4,000 kilometers, which is almost a quarter of the circumference of Mars.
Mars also has polar caps composed of water ice and frozen carbon dioxide. During different seasons, these polar caps expand and contract.
The presence of minerals that only form in the presence of liquid water suggests that Mars had liquid water on its surface in the past, raising the possibility that life may have once existed.
Rotation and translation
Mars has a rotation period similar to that of Earth, with a Martian day, known as the "sun", lasting 24.6 hours.
Its orbital period around the Sun is approximately 687 Earth days, meaning that a year on Mars lasts almost twice as long as a year on Earth. Mars' axial tilt is 25.2 degrees, similar to Earth's 23.5-degree tilt, resulting in Martian seasons comparable to Earth's, although each season lasts about twice as long.
The linear speed of Mars in its orbit around the Sun is approximately 86,871 km/h (24.13 km/s). This speed refers to the speed with which Mars moves along its orbital path.
The angular velocity of Mars, which measures the change of its angular position in orbit per unit time, is approximately 3.34 × 10⁻⁷ radians per second.
Moons of Mars: Phobos and Deimos
Mars has two small moons, Phobos and Deimos, which were discovered in 1877 by American astronomer Asaph Hall.
Phobos, the larger of the two, has a diameter of about 22.4 kilometers and orbits Mars at a distance of just 6,000 kilometers, completing one orbit in about 7.7 hours. On the other hand, Deimos, smaller, with a diameter of about 12.4 kilometers, orbits at a distance of 23,460 kilometers and takes 30.3 hours to complete one revolution around the planet.
Both moons have irregular shapes and are covered in craters, suggesting they are asteroids captured by Mars' gravity. Phobos is in an orbit that is gradually taking it toward Mars, and is expected to eventually break up or collide with the planet.
Mars Exploration
Mars exploration has been a priority for space agencies for decades.
The first successful mission was NASA's Mariner 4 in 1965, which sent back the first close-up images of Mars. Since then, there have been many successful missions, including orbiters, landers and rovers.
The best-known rovers are Spirit, Opportunity, Curiosity, and Perseverance. These rovers have explored the Martian surface, searching for signs of past water and habitable conditions. Among these, the Perseverance mission stands out, which landed in 2021, and is currently searching for signs of past microbial life and collecting rock and soil samples that a future mission could bring back to Earth.
Potential for life
The question of whether Mars has ever supported life is one of the most intriguing topics in planetary science.
Missions have found evidence that Mars once had conditions that could have been suitable for life. This includes the presence of ancient river beds, minerals that form in liquid water, and methane in the atmosphere, which on Earth is largely produced by biological processes.
Appearances of Mars in the cinema
Mars has been a constant source of inspiration in cinema, capturing the public's imagination with stories of exploration, survival and extraterrestrial contact.
Here's a look at some of the most notable films that have explored the red planet:
"The Martian" (2015)
Based on the novel of the same name by Andy Weir, this film directed by Ridley Scott and starring Matt Damon follows the story of an astronaut who is stranded on Mars and must use his wits to survive while awaiting an unlikely rescue.
The film received praise for its scientific accuracy and focus on engineering and survival.
"Total Recall" (1990)
Directed by Paul Verhoeven and starring Arnold Schwarzenegger, this science fiction film is based on the short story "We Can Remember It for You Wholesale" by Philip K. Dick. It presents a futuristic, dystopian vision of Mars, where implanted memories and rebellions against an oppressive corporation play a central role.
"Red Planet" (2000)
Starring Val Kilmer and Carrie-Anne Moss, this film explores a rescue mission to Mars after a terraforming attempt goes wrong.
Although it received mixed reviews, it offers an intriguing look at the technical and human challenges of Martian colonization.
"Mission to Mars" (2000)
Directed by Brian De Palma, this film follows a team of astronauts on a mission to rescue a previous crew and discover the secrets of Mars. The film mixes elements of mystery and space exploration, although it also received mixed reviews for its pacing and narrative.
"John Carter" (2012)
Based on the series of novels by Edgar Rice Burroughs, this film directed by Andrew Stanton features an American Civil War veteran transported to Mars, where he becomes involved in a civil war between the planet's inhabitants.
Despite its commercial failure, the film is known for its visual effects and its ambitious adaptation of the original work.