A Martian is a native inhabitant of the planet Mars. Although the search for evidence of life on Mars continues, many science fiction writers have imagined what extraterrestrial life on Mars might be like. Some writers also use the word Martian to describe a human colonist on Mars.

Woking tripod
Sculpture of a Wellsian Martian Tripod in the town of Woking, England

Martians in fiction

The earliest known instances of the word "Martian", used as a noun instead of an adjective, were printed in late 1877. They appeared nearly simultaneously in England and the United States, in magazine articles detailing Asaph Hall's discovery of the moons of Mars in August of that year.[1]

The next event to inspire the use of the noun Martian in print was the International Exposition of Electricity, which was hosted in Paris in the year 1881. During the four months of the exhibition, many people visited to witness such technological marvels as the incandescent light bulb and the telephone. One visitor came away wondering what kind of world such innovations might engender in the next 200 years. Writing anonymously, s/he assembled some speculations in an essay titled "The Year of Grace 2081", which enjoyed wide circulation.[2] The Martians enter the story late in the narrative. During a rest from international conflict on Earth, humans begin telecommunicating with Martians. "After a brief period passed in the exchange of polite messages", says the essayist, humans will decide to war with the Martians on some pretence of honor. The war that results is cataclysmic:

[Humans] will unite all their energies for the fabrication of mammoth engines which will discharge oceans of water, metal and fire right into the face of Mars. In return, the Martians will pelt them with aeroliths weighing three thousand tons, which will chip whole mountains off the Himalayas and make a big hole where Mont Blanc now exists.[3]

W. S. Lach-Szyrma's novel Aleriel, or A Voyage to Other Worlds (1883) was previously reputed to be the first published work to apply the word Martian as a noun. The usage is incidental; it occurs when Aleriel, the novel's protagonist, lands on Mars in a spacecraft called an "ether-car" (an allusion to aether, which was once postulated as a gaseous medium in outer space). Aleriel buries the car in snow "so that it might not be disturbed by any Martian who might come across it."[4]

War of the Worlds original cover bw
War of the Worlds reprinted in the August 1927 issue of Amazing Stories

Fifteen years after Aleriel, H. G. Wells' landmark novel The War of the Worlds (1898) was published by William Heinemann, Ltd., then a relatively new publishing house. The novel was revised numerous times, and has since been translated into many languages. In the story, the Martians are a technologically advanced race of octopus-like extraterrestrials who invade Earth because Mars is becoming too cold to sustain them. The Martians' undoing is a fatal vulnerability to Earth bacteria.

In his book Mars and Its Canals (1906), astronomer and businessman Percival Lowell conjectured that an extinct Martian race had once constructed a vast network of aqueducts to channel water to their settlements from Mars' polar ice caps, Planum Australe and Planum Boreum. Lowell did not invent this Martian canal hypothesis, but he supported it.[5] The belief that Mars had canals was based on observations Giovanni Schiaparelli made through his reflecting telescope. Although the telescope's image was fuzzy, Schiaparelli thought he saw long, straight lines on the Martian surface; some astronomers came to believe that these lines were structures built by Martians. This idea inspired Lowell, who returned to the subject in Mars As the Abode of Life (1910), in which he wrote a fanciful description of what this Martian society may have been like.[6] Although his description was based on almost no evidence, Lowell's words evoked vivid pictures in his readers' imaginations.

One of the people Lowell inspired was Edgar Rice Burroughs, who began writing his own story about Mars in the summer of 1911. The story is a planetary romance in which an American Civil War veteran named John Carter is transported to Mars when he walks inside a cave on Earth. He finds that Mars is populated by two species of warring humanoids, and he becomes embroiled in their conflict. In February 1912, an American pulp magazine called The All-Story published Burroughs' story as the first installment of a serial novel, which the editor titled Under the Moons of Mars (retitled A Princess of Mars in subsequent editions). The book was the first in Burroughs' Barsoom series.

Although the noun Martian can describe any organism from Mars, these and later works typically imagine Martians as a humanoid monoculture. Martian, in this sense, is more like the word human than the word Earthling. (Few writers describe a biodiverse Mars.) In science fiction, Martians are stereotypically imagined in one or more of the following ways: as alien invaders; as humanoids with a civilization that resembles one on Earth; as anthropomorphic animals; as beings with superhuman abilities; as humanoids with a lower intelligence than humans; as human colonists who adopt a Martian identity; and/or as an extinct race who possessed high intelligence.

Martians as invaders of Earth

Landingsite statue
The Martian Landing Site monument in West Windsor, New Jersey commemorates the 1938 broadcast of the radio drama The War of the Worlds, in which West Windsor is the first landing site of the Martian invasion. Many listeners believed the broadcast to be a news report.

H. G. Wells' novel The War of the Worlds (1898) and its various adaptations have been an extraordinary influence on science fiction writers for more than 100 years. Wells' Martians are a technologically advanced species with an ancient civilization. They somewhat resemble cephalopods, with large, bulky brown bodies and sixteen snake-like tentacles, in two groups of eight, around a quivering V-shaped mouth; they move around in 100 feet tall tripod fighting-machines they assemble upon landing, killing everything in their path. They invade Earth because Mars is dying, and they need a warmer planet to live. They attack cities in southern England, including London, with a deadly heat-ray they fire from a camera-like device on an articulated arm attached to their tripods; they also employ chemical warfare, using a poisonous "black smoke" launched from gun-like tubes. Mankind is saved by Earth bacteria, which kill the Martians within three weeks of their landing on Earth.

In Last and First Men (1930) Olaf Stapledon revisited Wells' theme of Martian invasion. Last and First Men summarizes tens of thousands of years of invasions and war between Martians and humans. Eventually, humans destroy the Martians' empire.

William Cameron Menzies' film Invaders from Mars (1953) fuses the tentacles of Wells' Martians with the idea of little green men to conceive a Martian Mastermind who enslaves tall, green, humanoid mutants. Tobe Hooper's remake of the film was released in 1986,

In his 1955 comic novel Martians, Go Home, Fredric Brown spoofs the Wellsian invasion, and reinterprets the Martian invader as a rude house guest with ulterior motives. Brown, too, employs the "little green men" trope to describe his annoying Martians.

Little green men recur in the 2009 video game Stalin vs. Martians, a spoof of earlier strategy video games. As the president of the Soviet Union, the player defends Earth from Martian invasion. This time the caricature of the Martians appears to be influenced by H. R. Giger.

In Spaced Invaders (1990), a group of Martians invade a town in the Midwestern United States during a re-broadcast of the Orson Welles' 1938 radio dramatization of The War of the Worlds.

In 1948, Warner Bros. introduced a new villain to their animated films: Marvin the Martian, a short, slender figure with comically oversized eyes, hands, and feet, but with no visible mouth. His big, spherical head is either completely black or overshadowed by his crested helmet. His clothing is patterned on that of Mars, the god of war in Roman mythology. In Marvin's film debut, Haredevil Hare (1948), he attempts to blow up Earth because it "obscures [his] view of Venus", but is thwarted by Bugs Bunny.

Another film that imagines Martians as ineffectual invaders is Mars Attacks! (1996), a black comedy based on a Topps trading card series. Here, the Martian invaders are loud, irritating, and dim-witted, despite having oversized heads with extremely large, protruding brains. The film was written by Jonathan Gems, and directed by Tim Burton.

In the Superman story "Black Magic on Mars" (1950),[7] the conception of Martians is more grave: The Martian invaders Superman faces are led by a dictator called Martler, who is an admirer of Adolf Hitler.

In "Will the Real Martian Please Stand Up?", a 1961 episode of The Twilight Zone, Martians attempt to colonize Earth, but are thwarted by Venusians. Here, the Martians are disguised as humans, but towards the end of the episode we see that they have three eyes.

In Mars Needs Moms (2007), a picture book by Berkeley Breathed, Martians are squat, humanoid beings with antennae and skin color that varies by individual. When they travel to Earth, they wear transparent helmets and a bulbous, ribbed outer garment. In the story, a five-year-old boy learns to appreciate his mother after three Martians kidnap her while he sleeps. Writer-director Simon Wells and his wife Wendy adapted the picture book into the film Mars Needs Moms (2011).

Martians as civilized humanoids

In April 1911, about a year before The All-Story published the first installment of Burroughs' Under the Moons of Mars, Modern Electrics began publishing Hugo Gernsback's own romance, Ralph 124C 41+, which takes place on Earth. Gernsback's Martians live among the humans on Earth; they are taller and physically stronger than humans, with green skin and large eyes. The serial wasn't republished as a book until 1925.

1923 saw the publication of Aelita, or The Decline of Mars, a novel that is equally science fiction and political fiction. Its author, Soviet Russian writer Aleksey Nikolayevich Tolstoy, tells a story of a Soviet engineer who builds a rocket and invites an acquaintance to accompany him in it to Mars. There they find a humanoid race of Martians who are the offspring of both an elder Martian species and of humans from Atlantis. The Martians live in a class society; the workers rise up against the ruling class, but the revolution fails. All the while, Mars is entering a phase of climate change that threatens disaster for the population.

Red Planet (1932), a play cowritten by John L. Balderston and John Hoare, also deals with radical environmental change on Mars, except in this case it occurs through terraforming. Balderston was one of the few playwrights of the 20th century to adopt Mars or Martians as a subject for the stage. He was, however, also a screenwriter who specialized in fantasy film and horror film. Many years later, United Artists bought a screen adaptation that Balderston and fellow screenwriter Anthony Veiller wrote. Harry Horner directed the film, called Red Planet Mars, and it was released to cinemas in 1952. In the film, a scientist communicates with Martians by radio, and they tell him that Mars is a utopia. When the news circulates, it causes widespread unrest among the people of Western nations. The US government tries to silence further messages, then later announces that the Martians have informed them that they must all worship God in order to save themselves. After millions of people revolt against their governments, it seems the Martian communiques may have been a hoax.

Ray Bradbury's novel The Martian Chronicles (1950) depicts Martians as a refined and artistic race of golden-skinned beings who closely resemble humans. The Martians are almost completely wiped out by the diseases brought to Mars by human invaders. At the end of the book, the human inhabitants of Mars realize that they are the new Martians. The novel's themes and its portrayal of Martians resemble Bradbury's 1949 short story "Dark They Were, and Golden-Eyed".

Brothers Jim Thomas and John Thomas teamed with Graham Yost to write Mission to Mars (2000), a film that depicts Martians as tall, feminine, peaceful humanoids who left Mars to escape the havoc caused by a massive meteorite impact.

Edmond Hamilton's "A Conquest of Two Worlds" describes Martians as humanoid creatures with stilt-like limbs and large, bulging chests and heads. They live in tribal groups centered on oases and occasionally fight among themselves. After an accidental confrontation sparks war, they are all killed or enslaved by the invading human population.[8]

Martians as anthropomorphic animals

C. S. Lewis wrote, in Out of the Silent Planet (1938), about three humans who visit Mars and meet three different kinds of intelligent native creatures: The hrossa (bipedal "otter" men), the sorns/séroni (lean white giants), and the pfifltriggi (dwarves). They are dying out, but are resigned to their fate. The books also describe a prey animal called hnakra, which is hunted. The planet is ruled by the Oyarsa, an "eldil" (supernatural beings/spirits) whose job is to be the guardian of the planet and ruler of its peoples.

In four stories by Eric Frank Russell published between the early 1940s and mid-1950s—and collected inMen, Martians and Machines (1955)—a crew of humans and octopoid Martians are shipmates and compatriots on an interstellar voyage. During their travels, they encounter hostile aliens. Russell's Martians can survive in Earth-normal air pressures, but are more comfortable wearing low-pressure helmets and tease their shipmates about the soupy conditions on board.[9]

As a writer for Doctor Who, Brian Hayles created a Martian species of reptilian humanoids called the Ice Warriors, who move stiffly and speak in a husky whisper. Most of the Ice Warriors that the Doctor encounters are brutish and belligerent. As Mars' climate becomes less favorable to sustaining them, the Ice Warriors seek a new planet. These reptilians debuted in The Ice Warriors (1967), a Doctor Who television serial about an impending ice age in Earth's future. As British scientists try to slow or avert a glacier encroaching on Great Britain, they find an Ice Warrior near their base, frozen in the glacier, and apparently in suspended animation. No one knows the being's identity, but they understand that it is probably from another planet. When the Ice Warrior revives, he attacks Jamie McCrimmon and kidnaps Victoria Waterfield. Other stories set in the future show the Martians eventually become more peaceful and are members of the Galactic Federation, though some want to return to their warlike ways.

Human colonists as Martians

Many of Robert A. Heinlein's Martian characters are humans born and raised on Mars. In Red Planet (1949), boys attend a boarding school in a human colony on Mars. A population of native Martians tolerates them until the colony administrator threatens a Martian child. The Martians demand that the humans leave Mars, but a human doctor convinces them to reconsider.

In Heinlein's 1956 novel Double Star, humans have colonized the solar system, and a politician on Mars faces the civil rights issue of granting a native Martian species (who are second-class citizens) the right to vote.

In Philip K. Dick's novel Martian Time-Slip (1964), a human colony on Mars is trying to cope with arduous environmental conditions. They treat an aboriginal race, whom they call "Bleekmen", with casual racism. In The Three Stigmata of Palmer Eldritch (1965), Mars has no indigenous life. To cope with the sterile habitat, the human colonists abuse drugs such as "Can-D" and "Chew-Z".

Dick previously published a shorter version of the story in 1963, called All We Marsmen. Like Heinlein's Double Star, All We Marsmen was conceived at a time in US history when many marginalized people were fighting especially vehemently for more civil rights. US President Lyndon B. Johnson signed the Civil Rights Act of 1964 into law on 2 July 1964.1

Total Recall (1990) is a science fiction action film about an apparently unsophisticated construction worker who turns out to be a freedom fighter from Mars who has been relocated to Earth. He later learns of an alien artifact that proves Mars harbored life before the human colonization.

The character designers for Futurama, a comical American animated series, imagine Mars after human colonization as being like the American frontier; native Martians inhabit zones analogous to Indian reservations. One of the series principal characters, Amy Wong, is a scientist of Chinese descent who was born on Mars. Her parents have amassed an enormous fortune and enterprise there.

Rebecca Bloomer's novel Unearthed (2011), the first in a series, describes a futuristic human colony on Mars amidst the populations of native Martians.

Martians as an extinct race

Mars Hubble
A photograph of Mars captured by the Hubble Space Telescope on 26 June 2001

For his Known Space series of novels, Larry Niven conceived humanoid Martians with a primitive material culture who inhabit an environment of red dust and nitric acid, and for whom water is lethal. In the 1973 novel Protector, a man named Jack Brennan allies himself with a ruthless, xenophobic humanoid species called the Pak. To preclude the possibility future competition for Pak offspring, Brennan engineers a Martian genocide by sending an ice-covered asteroid to collide with Mars.

In Dennis Feltham Jones' 1977 novel Colossus and the Crab, Martian life predated life on Earth, but faced a process of devolution as conditions on the planet worsened.

Quatermass and the Pit (1958–59) is a British television serial in which a crashed spacecraft is discovered in London. The wreck evidences that the human population of Earth resulted from the experiments of a Martian civilisation, now long dead. A film remake was released in 1967.

Ghosts of Mars (2001) human invaders war with Martians in an attempt to conquer Mars.

In the Invader Zim episode "Battle of the Planets" (2001), Zim discovers that a Martian race died off after converting Mars into a giant spacecraft.

In Doom 3 (2004), the entire Martian race sacrificed itself many millennia ago in order to prevent a demonic invasion of our universe. By the year 2145, humanity has colonized Mars and begun excavating the ruins of their civilization, recovering several important artifacts. One of these artifacts—known as the Soul Cube—is the player's most valuable tool in combating a second demonic invasion, as it is the only weapon capable of killing the Cyberdemon.

Martians as superbeings

Isaac Asimov's David Starr, Space Ranger, the first novel in the Lucky Starr series, features a race of Martians who have retreated into vast artificial underground caverns half a million years ago. These Martians are incorporeal, telepathic beings, peaceful yet curious about humanity. They have access to advanced technologies completely incomprehensible to human beings, like personal energy shield generators the size of a fabric mask.

In Robert Heinlein's Stranger in a Strange Land (1961), a man raised by native Martians emigrates to Earth, where he must reacclimate. In the novel he functions as a Christ figure. Soon he demonstrates psychic powers, superhuman intelligence, and an ability to manipulate higher dimensions. He founds a church on Earth based on Martian philosophy, and starts a cultural shift. At the novel's climax, he is murdered by a mob from a rival religious group.

In 1963, American television network CBS premiered a sitcom called My Favorite Martian. The series proved popular in the US, especially during the first season, and CBS broadcast more than one hundred episodes before canceling it when the third season ended in 1966. In this comedy, a Martian anthropologist (who passes for human in most respects) crashes on Earth, where he is harbored by an American man who keeps the Martian's identity secret. Also secret are the Martian's extraordinary abilities, not the least of which are invisibility and telepathy. CBS's rival networks, NBC and ABC, did not fail to notice the success of My Favorite Martian, or the comic potential of a character with secret powers. In 1964, ABC introduced Bewitched (a sitcom about a married, suburban witch), and NBC countered the following year with I Dream of Jeannie, a sitcom about an astronaut who discovers and marries a genie.

In Captain Scarlet and the Mysterons (1967–68), the Mysterons are a race of invisible superbeings from Mars who are at war with humans from Earth. The conflict begins when Captain Black, a human officer investigating radio signals from Mars, mistakes a surveillance camera for a weapon. In violation of his orders, he attacks, but the Mysterons immediately repair the damage he caused. The conflict escalates, and the Mysterons attempt to assassinate the president of Earth.

DC Comics introduced the first Martian superhero to the DC Universe in 1955. Martian Manhunter (J'onn J'onzz), a green humanoid who is believed to be the last of the peaceful Green Martians, joins the Justice League. Meanwhile, the warlike, shapeshifting White Martians regard the Green Martians as enemies. The White Martians adopt a humanoid form which, they say, expresses their distinctive philosophy. DC introduced a White Martian superhero, Miss Martian, in 2006. A third race, the Yellow Martians, may or may not have survived as long as the Green and White Martians.

See also


  1. ^ Brown, Peter Jensen. "The World's First Martian". Early Sports and Pop Culture Blog. Retrieved 10 June 2014.
  2. ^ Brown, Peter Jensen. "The Future as Seen from the Dawn of the Electrical Age". Early Sports 'n Pop-Culture Blog. Retrieved 2016-03-09.
  3. ^ "The Year of Grace 2081". Truth: A Weekly Journal, Volume X (Nos. 236 to 260). London. 1881. p. 383. Retrieved 2016-03-09.
  4. ^ Forsyth, Mark (16 September 2010). "Wladyslaw Lach-Szyrma and the First Martian". The Inky Fool. Retrieved 4 August 2013.
  5. ^ Alfred Russel Wallace refuted Lowell's conjecture in his own book Is Mars Habitable? (1907), in which he argues that neither the atmosphere of Mars nor its climate could sustain life as we understand it.
  6. ^ Caplinger, Michael (April 1995). "Life on Mars". Malin Space Science Systems. Archived from the original on 27 May 2008. Retrieved 4 August 2013.
  7. ^ "Black Magic on Mars" Superman 62 (January 1950), DC Comics
  8. ^ Hamilton, Edmond. "A Conquest of Two Worlds" in Wonder Stories, February 1932.
  9. ^ Russell, Eric Frank (1958). Men, Martians and Machines. New York, NY, USA: Berkeley Medallion. p. 10.

Further reading

Atmosphere of Mars

The atmosphere of the planet Mars is composed mostly of carbon dioxide. The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar). It ranges from a low of 30 pascals (0.0044 psi; 0.30 mbar) on Olympus Mons's peak to over 1,155 pascals (0.1675 psi; 11.55 mbar) in the depths of Hellas Planitia. This pressure is well below the Armstrong limit for the unprotected human body. Mars's atmospheric mass of 25 teratonnes compares to Earth's 5148 teratonnes; Mars has a scale height of 11.1 kilometres (6.9 mi) versus Earth's 8.5 kilometres (5.3 mi).The Martian atmosphere consists of approximately 96% carbon dioxide, 1.9% argon, 1.9% nitrogen, and traces of free oxygen, carbon monoxide, water and methane, among other gases, for a mean molar mass of 43.34 g/mol. There has been renewed interest in its composition since the detection of traces of methane in 2003 that may indicate life but may also be produced by a geochemical process, volcanic or hydrothermal activity.The atmosphere is quite dusty, giving the Martian sky a light brown or orange-red color when seen from the surface; data from the Mars Exploration Rovers indicate suspended particles of roughly 1.5 micrometres in diameter.On 16 December 2014, NASA reported detecting an unusual increase, then decrease, in the amounts of methane in the atmosphere of the planet Mars. Organic chemicals have been detected in powder drilled from a rock by the Curiosity rover. Based on deuterium to hydrogen ratio studies, much of the water at Gale Crater on Mars was found to have been lost during ancient times, before the lakebed in the crater was formed; afterwards, large amounts of water continued to be lost.On 18 March 2015, NASA reported the detection of an aurora that is not fully understood and an unexplained dust cloud in the atmosphere of Mars.On 4 April 2015, NASA reported studies, based on measurements by the Sample Analysis at Mars (SAM) instrument on the Curiosity rover, of the Martian atmosphere using xenon and argon isotopes. Results provided support for a "vigorous" loss of atmosphere early in the history of Mars and were consistent with an atmospheric signature found in bits of atmosphere captured in some Martian meteorites found on Earth. This was further supported by results from the MAVEN orbiter circling Mars, that the solar wind is responsible for stripping away the atmosphere of Mars over the years.In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier due to a massive, and unexpected, solar storm in the middle of the month.On 1 June 2018, NASA scientists detected signs of a dust storm (see image) on the planet Mars which may affect the survivability of the solar-powered Opportunity rover since the dust may block the sunlight (see image) needed to operate; as of 12 June, the storm is the worst ever recorded at the surface of the planet, and spanned an area about the size of North America and Russia combined (about a quarter of the planet); as of 13 June, Opportunity was reported to be experiencing serious communication problem(s) due to the dust storm; a NASA teleconference about the dust storm was presented on 13 June 2018 at 01:30 pm/et/usa and is available for replay. In July 2018, researchers reported that the largest single source of dust on the planet Mars comes from the Medusae Fossae Formation.On 7 June 2018, NASA announced a cyclical seasonal variation in atmospheric methane.

Climate of Mars

The climate of the planet Mars has been a topic of scientific curiosity for centuries, in part because it is the only terrestrial planet whose surface can be directly observed in detail from the Earth with help from a telescope.

Although Mars is smaller than the Earth, at 11% of Earth's mass, and 50% farther from the Sun than the Earth, its climate has important similarities, such as the presence of polar ice caps, seasonal changes and observable weather patterns. It has attracted sustained study from planetologists and climatologists. While Mars's climate has similarities to Earth's, including periodic ice ages, there are also important differences, such as much lower thermal inertia. Mars's atmosphere has a scale height of approximately 11 km (36,000 ft), 60% greater than that on Earth. The climate is of considerable relevance to the question of whether life is or was present on the planet. The climate briefly received more interest in the news due to NASA measurements indicating increased sublimation of one near-polar region leading to some popular press speculation that Mars was undergoing a parallel bout of global warming, although Mars's average temperature has actually cooled in recent decades, and the polar caps themselves are growing.

Mars has been studied by Earth-based instruments since the 17th century, but it is only since the exploration of Mars began in the mid-1960s that close-range observation has been possible. Flyby and orbital spacecraft have provided data from above, while landers and rovers have measured atmospheric conditions directly. Advanced Earth-orbital instruments today continue to provide some useful "big picture" observations of relatively large weather phenomena.

The first Martian flyby mission was Mariner 4, which arrived in 1965. That quick two-day pass (July 14–15, 1965) with crude instruments contributed little to the state of knowledge of Martian climate. Later Mariner missions (Mariner 6, and Mariner 7) filled in some of the gaps in basic climate information. Data-based climate studies started in earnest with the Viking program landers in 1975 and continue with such probes as the Mars Reconnaissance Orbiter.

This observational work has been complemented by a type of scientific computer simulation called the Mars general circulation model. Several different iterations of MGCM have led to an increased understanding of Mars as well as the limits of such models.

Colonization of Mars

Mars is the focus of much scientific study about possible human colonization. Mars's surface conditions and past presence of water make it arguably the most hospitable planet in the Solar System besides Earth. Mars requires less energy per unit mass (delta-v) to reach from Earth than any planet, other than Venus.

Permanent human habitation on other planets, including Mars, is one of science fiction's most prevalent themes. As technology advances, and concerns about humanity's future on Earth increase, arguments favoring space colonization gain momentum. Other reasons for colonizing space include economic interests, long-term scientific research best carried out by humans as opposed to robotic probes, and sheer curiosity.

Both private and public organizations have made commitments to researching the viability of long-term colonization efforts and to taking steps toward a permanent human presence on Mars. Space agencies engaged in research or mission planning include NASA, Roscosmos, and the China National Space Administration. Private organizations include SpaceX, Lockheed Martin, and Boeing.

Life on Mars

The possibility of life on Mars is a subject of significant interest to astrobiology due to its proximity and similarities to Earth. To date, no proof has been found of past or present life on Mars. Cumulative evidence shows that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms. The existence of habitable conditions does not necessarily indicate the presence of life.Scientific searches for evidence of life began in the 19th century, and they continue today via telescopic investigations and deployed probes. While early work focused on phenomenology and bordered on fantasy, the modern scientific inquiry has emphasized the search for water, chemical biosignatures in the soil and rocks at the planet's surface, and biomarker gases in the atmosphere.Mars is of particular interest for the study of the origins of life because of its similarity to the early Earth. This is especially so since Mars has a cold climate and lacks plate tectonics or continental drift, so it has remained almost unchanged since the end of the Hesperian period. At least two-thirds of Mars's surface is more than 3.5 billion years old, and Mars may thus hold the best record of the prebiotic conditions leading to abiogenesis, even if life does not or has never existed there.Following the confirmation of the past existence of surface liquid water, the Curiosity and Opportunity rovers started searching for evidence of past life, including a past biosphere based on autotrophic, chemotrophic, or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable. The search for evidence of habitability, taphonomy (related to fossils), and organic compounds on Mars is now a primary NASA and ESA objective.

The findings of organic compounds inside sedimentary rocks and of boron on Mars are of interest as they are precursors for prebiotic chemistry. Such findings, along with previous discoveries that liquid water was clearly present on ancient Mars, further supports the possible early habitability of Gale Crater on Mars. Currently, the surface of Mars is bathed with radiation, and when reacting with the perchlorates on the surface, it may be more toxic to microorganisms than thought earlier. Therefore, the consensus is that if life exists —or existed— on Mars, it could be found or is best preserved in the subsurface, away from present-day harsh surface processes.

In June 2018, NASA announced the detection of seasonal variation of methane levels on Mars. Methane could be produced by microorganisms or by geological means. The European ExoMars Trace Gas Orbiter started mapping the atmospheric methane in April 2018, and the 2020 ExoMars rover will drill and analyze subsurface samples, while the NASA Mars 2020 rover will cache dozens of drill samples for their potential transport to Earth laboratories in the late 2020s or 2030s.


Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as the "Red Planet" because the reddish iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth.

The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan.

There are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers. Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% of the Earth's, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. 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 meters (36 ft). In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.94, which is surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 kilometers (190 mi) across when Earth and Mars are closest because of Earth's atmosphere.

Martian Manhunter

The Martian Manhunter (J'onn J'onzz) is a fictional superhero appearing in American comic books published by DC Comics. Created by writer Joseph Samachson and designed by artist Joe Certa, the character first appeared in the story "The Manhunter from Mars" in Detective Comics #225 (Nov. 1955). Martian Manhunter is one of the seven original members of the Justice League of America and one of the most powerful beings in the DC Universe.

J'onzz has been featured in other DC Comics-endorsed products, such as video games, television series, animated films, and merchandise like action figures and trading cards. The character was ranked #43 on IGN's greatest comic book hero list. J'onzz was played by David Ogden Stiers in the 1997 Justice League of America live-action television pilot. Phil Morris also portrayed him in the television series Smallville. David Harewood portrays the human guise of Martian Manhunter on Supergirl.

Martian meteorite

A Martian meteorite is a rock that formed on the planet Mars and was then ejected from Mars by the impact of an asteroid or comet, and finally landed on the Earth. Of over 61,000 meteorites that have been found on Earth, 224 were identified as Martian as of January 2019. These meteorites are thought to be from Mars because they have elemental and isotopic compositions that are similar to rocks and atmosphere gases analyzed by spacecraft on Mars. In October 2013, NASA confirmed, based on analysis of argon in the Martian atmosphere by the Mars Curiosity rover, that certain meteorites found on Earth thought to be from Mars were indeed from Mars.The term does not refer to meteorites found on Mars, such as Heat Shield Rock.

On January 3, 2013, NASA reported that a meteorite, named NWA 7034 (nicknamed "Black Beauty"), found in 2011, in the Sahara desert, was determined to be from Mars and found to contain ten times the water of other Mars meteorites found on Earth. The meteorite contains components as old as 4.42 ± 0.07 Ga (billion years), and was heated during the Amazonian geologic period on Mars.

Martian soil

Martian soil is the fine regolith found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil, including its toxicity due to the presence of perchlorates. The term Martian soil typically refers to the finer fraction of regolith. On Earth, the term "soil" usually includes organic content. In contrast, planetary scientists adopt a functional definition of soil to distinguish it from rocks. Rocks generally refer to 10 cm scale and larger materials (e.g., fragments, breccia, and exposed outcrops) with high thermal inertia, with areal fractions consistent with the Viking Infrared Thermal Mapper (IRTM) data, and immobile under current aeolian conditions. Consequently, rocks classify as grains exceeding the size of cobbles on the Wentworth scale.

This approach enables agreement across Martian remote sensing methods that span the electromagnetic spectrum from gamma to radio waves. ‘‘Soil’’ refers to all other, typically unconsolidated, material including those sufficiently fine-grained to be mobilized by wind. Soil consequently encompasses a variety of regolith components identified at landing sites. Typical examples include: bedform armor, clasts, concretions, drift, dust, rocky fragments, and sand. The functional definition reinforces a recently proposed genetic definition of soil on terrestrial bodies (including asteroids and satellites) as an unconsolidated and chemically weathered surficial layer of fine-grained mineral or organic material exceeding centimeter scale thickness, with or without coarse elements and cemented portions.Martian dust generally connotes even finer materials than Martian soil, the fraction which is less than 30 micrometres in diameter. Disagreement over the significance of soil's definition arises due to the lack of an integrated concept of soil in the literature. The pragmatic definition "medium for plant growth" has been commonly adopted in the planetary science community but a more complex definition describes soil as "(bio)geochemically/physically altered material at the surface of a planetary body that encompasses surficial extraterrestrial telluric deposits." This definition emphasizes that soil is a body that retains information about its environmental history and that does not need the presence of life to form.

Martian spherules

Martian spherules (also known as blueberries due to their blue hue in false-color images released by NASA) are the abundant spherical hematite inclusions discovered by the Mars rover Opportunity at Meridiani Planum on the planet Mars. They are found in situ embedded in a sulfate salt evaporitic matrix, and also loose on the surface.

Marvin the Martian

Marvin the Martian is a character from Warner Bros.' Looney Tunes and Merrie Melodies cartoons.

Miss Martian

Miss Martian (real name M'gann M'orzz, alias Megan Morse) is a fictional superheroine appearing in American comic books published by DC Comics. The character's first appearance outside of comics was in the animated series Young Justice, where she is voiced by Danica McKellar. In 2016, the second season of the live action Supergirl series on The CW the character appears for the first time in live action played by Sharon Leal. The show's interpretation of the character has earned a number of positive reviews.

Moons of Mars

The two moons of Mars are Phobos and Deimos. Both were discovered by Asaph Hall in August 1877 and are named after the Greek mythological twin characters Phobos (panic/fear) and Deimos (terror/dread) who accompanied their father Ares into battle. Ares, god of war, was known to the Romans as Mars.

Compared to the Earth's moon, Phobos and Deimos are small. Phobos has a diameter of 22.2 km (13.8 mi) and a mass of 1.08×1016 kg, while these measures for Deimos are 12.6 km (7.8 mi) and 2.0×1015 kg. Phobos orbits closer to Mars, with a semi-major axis of 9,377 km (5,827 mi) and an orbital period of 7.66 hours; Deimos's semi-major axis is 23,460 km (14,580 mi) with an orbital period of 30.35 hours.

Terraforming of Mars

Terraforming of Mars is a hypothetical process of planetary engineering by which the surface and climate of Mars would be deliberately changed to make large areas of the environment hospitable to humans, thus making the colonization of Mars safer and sustainable.

There are a few proposed terraforming concepts, some of which present prohibitive economic and natural resource costs. As of 2019 it is not feasible, using existing technology, to terraform Mars. Any climate change induced in the near term is proposed to be driven by greenhouse warming produced by an increase in atmospheric CO2 and a consequent increase in atmospheric water vapor, but Mars does not retain enough carbon dioxide that could practically be put back into the atmosphere to warm it.

The Martian (film)

The Martian is a 2015 science fiction film directed by Ridley Scott and starring Matt Damon. The Martian, a novel by Andy Weir, served as the screenplay adapted by Drew Goddard. The film depicts an astronaut's lone struggle to survive on Mars after being left behind, and efforts to rescue him. It also stars Jessica Chastain, Kristen Wiig, Jeff Daniels, Michael Peña, Kate Mara, Sean Bean, Sebastian Stan, Donald Glover, Aksel Hennie, and Chiwetel Ejiofor.

The film, produced through 20th Century Fox, is a co-production of the United States and the United Kingdom. Producer Simon Kinberg began developing the film after Fox optioned the novel in March 2013, which Drew Goddard adapted into a screenplay and was initially attached to direct, but the film did not move forward. Scott replaced Goddard, and with Damon in place as the main character, production was approved. Filming began in November 2014 and lasted approximately seventy days. Twenty sets were built on a sound stage in Budapest, Hungary, one of the largest in the world. Wadi Rum in Jordan was also used as a backdrop for filming.

The film premiered at the 2015 Toronto International Film Festival on September 11, 2015, while the London premiere was held on September 24, 2015. The film was released in the United Kingdom on September 30, 2015 and in the United States on October 2, 2015 in 2D, 3D, IMAX 3D and 4DX. It received positive reviews and grossed over $630 million worldwide, becoming Scott's highest-grossing film to date, as well as the 10th highest-grossing film of 2015. It received several accolades, including the Golden Globe Award for Best Motion Picture – Musical or Comedy, seven Academy Award nominations, including Best Picture and Best Adapted Screenplay for Goddard, and the 2016 long form Hugo Award for Best Dramatic Presentation. Damon won the Golden Globe Award for Best Actor – Motion Picture Musical or Comedy and was nominated for several awards including the Academy Award for Best Actor, the BAFTA Award for Best Actor in a Leading Role, and the Critic's Choice Award for Best Actor.

Timekeeping on Mars

Various schemes have been used or proposed for timekeeping on the planet Mars independently of Earth time and calendars.

Mars has an axial tilt and a rotation period similar to those of Earth. Thus it experiences seasons of spring, summer, autumn and winter much like Earth, and its day is about the same length. Its year is almost twice as long as Earth's, and its orbital eccentricity is considerably larger, which means among other things that the lengths of various Martian seasons differ considerably, and sundial time can diverge from clock time more than on Earth.

Water on Mars

Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere, and occasionally as low-volume liquid brines in shallow Martian soil. The only place where water ice is visible at the surface is at the north polar ice cap. Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole and in the shallow subsurface at more temperate conditions. More than 21 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters (115 ft). Even more ice is likely to be locked away in the deep subsurface.Some liquid water may occur transiently on the Martian surface today, but limited to traces of dissolved moisture from the atmosphere and thin films, which are challenging environments for known life. No large standing bodies of liquid water exist on the planet's surface, because the atmospheric pressure there averages just 600 pascals (0.087 psi) – about 0.6% of Earth's mean sea level pressure – leading to rapid evaporation or rapid freezing of liquid water and sublimation of water ice. Before about 3.8 billion years ago, Mars may have had a denser atmosphere and higher surface temperatures, allowing vast amounts of liquid water on the surface, possibly including a large ocean that may have covered one-third of the planet. Water has also apparently flowed across the surface for short periods at various intervals more recently in Mars' history. On December 9, 2013, NASA reported that, based on evidence from the Curiosity rover studying Aeolis Palus, Gale Crater contained an ancient freshwater lake that could have been a hospitable environment for microbial life.Many lines of evidence indicate that water ice is abundant on Mars and it has played a significant role in the planet's geologic history. The present-day inventory of water on Mars can be estimated from spacecraft imagery, remote sensing techniques (spectroscopic measurements, radar, etc.), and surface investigations from landers and rovers. Geologic evidence of past water includes enormous outflow channels carved by floods, ancient river valley networks, deltas, and lakebeds; and the detection of rocks and minerals on the surface that could only have formed in liquid water. Numerous geomorphic features suggest the presence of ground ice (permafrost) and the movement of ice in glaciers, both in the recent past and present. Gullies and slope lineae along cliffs and crater walls suggest that flowing water continues to shape the surface of Mars, although to a far lesser degree than in the ancient past.

Although the surface of Mars was periodically wet and could have been hospitable to microbial life billions of years ago, the current environment at the surface is dry and subfreezing, probably presenting an insurmountable obstacle for living organisms. In addition, Mars lacks a thick atmosphere, ozone layer, and magnetic field, allowing solar and cosmic radiation to strike the surface unimpeded. The damaging effects of ionizing radiation on cellular structure is another one of the prime limiting factors on the survival of life on the surface. Therefore, the best potential locations for discovering life on Mars may be in subsurface environments. On November 22, 2016, NASA reported finding a large amount of underground ice on Mars; the volume of water detected is equivalent to the volume of water in Lake Superior. In July 2018, Italian scientists reported the discovery of a subglacial lake on Mars, 1.5 km (0.93 mi) below the southern polar ice cap, and extending sideways about 20 km (12 mi), the first known stable body of water on the planet.Understanding the extent and situation of water on Mars is vital to assess the planet’s potential for harboring life and for providing usable resources for future human exploration. For this reason, "Follow the Water" was the science theme of NASA's Mars Exploration Program (MEP) in the first decade of the 21st century. Discoveries by the 2001 Mars Odyssey, Mars Exploration Rovers (MERs), Mars Reconnaissance Orbiter (MRO), and Mars Phoenix lander have been instrumental in answering key questions about water's abundance and distribution on Mars. The ESA's Mars Express orbiter has also provided essential data in this quest. The Mars Odyssey, Mars Express, MRO, and Mars Science Lander Curiosity rover are still sending back data from Mars, and discoveries continue to be made.

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