Barsoom is a fictional representation of the planet Mars created by American pulp fiction author Edgar Rice Burroughs. The first Barsoom tale was serialized as Under the Moons of Mars in pulp magazine The All-Story from February to July 1912 and published compiled as a novel as A Princess of Mars in 1917. It features John Carter, a late-19th-century American Confederate veteran who is mysteriously transported from Earth to the dying world of Mars where he meets and romances the beautiful Martian princess Dejah Thoris. Ten sequels followed over the next three decades, further extending his vision of Barsoom and adding other characters.

The Barsoom series, particularly the first novel, is universally considered a major influence on early science fiction. Junot Díaz writes:
The novel became a seminal text in the early science fiction canon, inspiring a slew of imitators and even a pair of related genres, the planetary romance and the sword-and-planetary, practiced by the likes of Leigh Brackett and Michael Moorcock and which you will still find examples of being written today.

Series
Burroughs began writing the Barsoom books in the second half of 1911 and produced one volume a year between 1911 and 1914; seven more were produced between 1921 and 1941. The first Barsoom tale was serialized in The All-Story magazine as Under the Moons of Mars (1911), and then published in hardcover as the complete novel A Princess of Mars (1917). The final Barsoom tale was a novella, Skeleton Men of Jupiter, published in Amazing Stories in February 1943. The novel editions of A Princess of Mars, The Gods of Mars and Llana of Gathol contain newly written forewords describing Edgar Rice Burroughs' interactions with John Carter, who is described as Burroughs' great-uncle.

Collectively, this series of novels has been referred to as the Martian Series.

Etymology
Burroughs frequently invented words of the languages spoken by the people in his novels, and used these extensively in the narrative. In Thuvia, Maid of Mars he included a glossary of Barsoomian words used in the first four novels. The word "Barsoom", the native Martian word for Mars, is composed of the Martian name for planet, "soom", and the Martian word for eight, "bar". This reflects counting Mars as the eighth body in the inner solar system, by counting not just planets, but the Sun and the satellites of Earth and of Mars.

Character focusA Princess of Mars, the first novel in the Barsoom series, with its sequels The Gods of Mars and The Warlord of Mars, form a trilogy centered upon protagonist John Carter and damsel in distress Dejah Thoris. John Carter's and Dejah Thoris's son Carthoris is also introduced as a minor character in The Gods of Mars, as is Thuvia.

Three other books focus on their descendants: Carthoris, in Thuvia, Maid of Mars, his sister, Tara of Helium, in The Chessmen of Mars, and Tara's daughter, Llana of Gathol, in Llana of Gathol.

Ulysses Paxton, another Earth man transported to Mars, is the focus of The Master Mind of Mars, and the rest of the books focus on John Carter's later adventures (Swords of Mars and John Carter of Mars), or on native Martian characters (A Fighting Man of Mars and Synthetic Men of Mars).

Form
Most of the Barsoom books are novels, but two are collections of shorter works: Llana of Gathol has four linked novelettes, originally published in Amazing Stories during 1941, and John Carter of Mars is composed of two novellas.

Most are first-person narratives. John Carter narrates A Princess of Mars, The Gods of Mars, The Warlord of Mars, Swords of Mars, the four novellas in Llana of Gathol, and "Skeleton Men of Jupiter" in John Carter of Mars. Ulysses Paxton narrates one, The Master Mind of Mars. Martian guardsman Vor Daj narrates Synthetic Men of Mars, and Martian navy officer Tan Hadron narrates A Fighting Man of Mars. Two other novels, Thuvia, Maid of Mars and The Chessmen of Mars, are written in the third person, as is "John Carter and the Giant of Mars" in John Carter of Mars.

Introductions
Beginning with A Princess of Mars, Burroughs established a practice which continued in the four sequels of introducing the novel as if a factual account passed on to him personally, wherein John Carter appears as an avuncular figure known to his family for years. The same device appears in several sequels: The Gods of Mars; The Chessmen of Mars; Swords of Mars; and Llana of Gathol.

Authorship
All the Barsoom tales were published under the name of Edgar Rice Burroughs, except Under the Moons of Mars, the first publication of A Princess of Mars, which was published under the pseudonym "Norman Bean". Burroughs had actually typed "Normal Bean" (meaning not insane) on his submitted manuscript; but his publisher's typesetter changed it to "Norman". The first novella in John Carter of Mars, "John Carter and the Giant of Mars", is thought to have been penned by Burroughs' son John "Jack" Coleman Burroughs, although allegedly revised by his father. It was recognized by fans, upon publication, as unlikely of being Burroughs' work, as the writing is of a juvenile quality compared with that of Burroughs' other stories.

Genre
The stories are science fantasy, belonging to the subgenre planetary romance, which has strong elements of both science fiction and fantasy. Planetary romance stories are similar to sword and sorcery tales, but include scientific aspects. They mostly take place on the surface of an alien world, frequently include sword fighting, monsters, supernatural elements such as telepathic abilities, and civilizations similar to Earth in pre-technological eras, particularly with the inclusion of dynastic or religious social structures. Spacecraft appear in the stories, but are not central to the story. The series can also be classified as the closely related genre sword and planet, which consists of what are essentially sword and sorcery stories that take place on another planet.

The stories also share a number of elements with westerns in that they feature desert landscapes, women taken captive and a final confrontation with the antagonist.

Burroughs' Barsoom stories are considered seminal planetary romances. While examples existed prior to the publication of his works, they are the principal influence on the many works of this type that followed. His style of planetary romance has ceased to be written and published in the mainstream, though his books remain in print.

Plot
Like most of Burroughs' fiction, the novels in the series are mostly travelogues, feature copious violence, and often depict civilized heroes captured by uncivilized cultures and mimicking their captors to survive.

Most Barsoom novels follow a familiar plot structure wherein a hero is forced to a far-off location in search of a woman kidnapped by an odious but powerful villain.

Female characters are likely to be virtuous and fight off amorous advances and other dangers until able to connect with the hero; who himself fights a variety of enemies and deposes petty rulers of severely repressed populations, usually with the assistance of a native.

Motifs
The world of Barsoom is morally unambiguous: characters are either good or evil; there is no sense of moral relativity. A sense of honor transcends race or political affiliation, and characters fight alongside one another and against their adversaries because it is the right thing to do. Qualities of compassion, loyalty, and bravery are celebrated, and callousness, deception, and cowardice are frowned upon.

Typically the novels include descriptions of aspects of the Martian world such as the architecture, and the presence of desolate landscapes punctuated by abandoned cities, technological achievements, advanced medicine, cultural elements such as religious practices and eating habits, breeding practices, and methods of population control. Many lost cities and civilizations and journeys into forgotten underworlds appear across the series, and the environment beyond the cities is populated by a variety of ferocious beasts, many roughly equivalent with Earth creatures and most bearing multiple sets of limbs. There are numerous examples of striking coincidences and dei ex machina usually to the benefit of the protagonists.

Mad scientists also appear, Ras Thavas from The Master Mind of Mars and Synthetic Men of Mars being the principal example, although another plays a prominent role in A Fighting Man of Mars. Instances of the use of superstition by religious cults to control and manipulate others are also common.A Princess of Mars was possibly the first fiction of the 20th century to feature a constructed language; although Barsoomian was not particularly developed, it did add verisimilitude to the narrative.

Villains
Most villains in the Barsoom series are implacably evil or are rulers or despots of major empires or of hidden fiefdoms. They are usually hated by their subjects and possess a voracious sexual appetite, usually directed towards the heroine. The pattern is established by Tharkian Jeddak Tal Hajus in the first novel, A Princess of Mars. Further examples include Salensus Oll of The Warlord of Mars, Nutus of Dusar in Thuvia, Maid of Mars, and Ul Vas, Jeddak of the Tarids in Swords of Mars.

Principal characters

Earthmen

John Carter: Captain John Carter is an Earthman who originated in Virginia. He fought in the American Civil war on the Confederate side. After the war he moved to the southwest US to work as a prospector. In 1866 he and his prospector partner struck it rich, but the partner was killed by American Indians, and Carter took refuge in a cave, where he was overcome by smoke that was some kind of cave gas, and while looking up at Mars in the sky, he is then teleported to Mars. He effectively disappeared for ten years [while on Mars], and was believed dead, but re-emerged in New York in 1876, settling on the Hudson. He appeared to die in 1886, leaving instructions for Burroughs, who refers to him as an 'uncle', to entomb him in a crypt, and leaving Burroughs with the manuscript of A Princess of Mars with instructions not to publish it for another 21 years. He has no memory before the age of 30 and seems never to age. He is adept with command, horsemanship, swords, and all weapons. He is  tall, with black hair and steel-gray eyes. He is honorable, courageous, and eternally optimistic, even in the face of certain death. On Mars, he encounters both formidable alien creatures and various warring Martian races, wins the hand of Martian princess Dejah Thoris, and rises to the position of Warlord of Mars. Carter is the protagonist of the first three novels, which together comprise the initial trilogy. Carter also headlines the eighth, tenth, and eleventh books, as well as being a major secondary character in the fourth and ninth novels.
Ulysses Paxton: The central character in The Master Mind of Mars. Paxton is a soldier in the First World War who is transported to Barsoom after he is mortally wounded, and subsequently becomes an assistant to Barsoomian scientist Ras Thavas.

Martians
Dejah Thoris: A Princess of Helium; courageous, chaste, and resourceful despite frequent abduction by villains. The daughter of Mors Kajak, Jed (prince or king) of Lesser Helium and granddaughter of Tardos Mors, Jeddak (king or emperor) of Helium, she is highly aristocratic and fiercely proud of her heritage. She is introduced early in the first Barsoom novel, A Princess of Mars, and is the love interest of John Carter. She is a central character in the first three novels, and her capture by various enemies, and subsequent pursuit by John Carter, is a constant motivating force in these tales. She is a minor character in The Chessmen of Mars and John Carter of Mars.
Tars Tarkas: A Green Martian warrior unusually compassionate among his people, who befriends John Carter and fights many battles at his side. Carter helps him become Jeddak of his society and negotiates an alliance between them and the city-state of Helium, which results in the destruction of their enemies, the city of Zodanga, at the end of A Princess of Mars; but Tars Tarkas retains much of his earlier personality.
Thuvia of Ptarth: A Princess of Ptarth, who first appears in The Gods of Mars, as a slave girl, rescued by John Carter from the nefarious Therns, and later imprisoned with Carter's wife Dejah Thoris, in a prison which can only be opened once per year and remains by her side until the conclusion of The Warlord of Mars. Like many of Burroughs' Martian heroines, she is tough, courageous, and proud, and identifies strongly with her aristocratic position in Martian society. Also typically, she is abducted by evildoers who wish to use her for political gain in  Thuvia, Maid of Mars, her rescue providing primary motivation for the plot of that novel. She is a central character in Thuvia, Maid of Mars and love interest of John Carter and Dejah Thoris' son Carthoris.
Ras Thavas: A mad scientist who develops both brain-transplant techniques and a form of cloning; a principal character in both The Master Mind of Mars and Synthetic Men of Mars.
Tan Hadron: A young Red Martian navy officer and the central character of A Fighting Man of Mars.
Vor Daj: A soldier in John Carter's guard. Principal character in Synthetic Men of Mars, who spends much of the novel with his brain transplanted into a hideous but powerful synthetic body.
Gahan of Gathol: A prince of Gathol; love interest for Tara of Helium and father of Llana of Gathol; a principal character in The Chessmen of Mars.

Martian descendants of John Carter and Dejah Thoris

Carthoris: Son of John Carter and Dejah Thoris, who inherits his father's superior strength. A minor character in The Gods of Mars. A principal character in Thuvia, Maid of Mars and love interest of Thuvia.
Tara of Helium: Impetuous daughter of John Carter and Dejah Thoris, who runs away and gets involved in various perilous situations as a principal character in The Chessmen of Mars. Love interest of Gahan of Gathol and mother of Llana of Gathol.
Llana of Gathol: Granddaughter of John Carter and Dejah Thoris and daughter of Tara of Helium and Gahan of Gathol; a principal character in the stories collected in Llana of Gathol.

Environment
While Burroughs' Barsoom tales never aspired to anything other than escapism, his vision of Mars was loosely inspired by astronomical speculation of the time, especially that of Percival Lowell, that saw the planet as a formerly Earthlike world now becoming less hospitable to life due to its advanced age. Living on an aging planet, with dwindling resources, the inhabitants of Barsoom have become hardened and warlike, fighting one another to survive. Once a wet world with continents and oceans, Barsoom's seas gradually dried up, leaving it a dry planet of highlands interspersed with moss-covered dead sea bottoms. Abandoned cities line the former coasts. The last remnants of the former bodies of water are the Great Toonolian Marshes and the antarctic Lost Sea of Korus.

Barsoomians distribute their scarce water supplies via a worldwide system of canals, controlled by quarreling city-states at the junctures thereof. The idea of Martian "canals" stems from telescopic observations by 19th century astronomers who, beginning with Giovanni Schiaparelli in 1877, believed they saw networks of lines on the planet. Schiaparelli called them canali, meaning "channels" but mistranslated in English as "canals".  During the time Burroughs wrote his first Barsoom stories, the theory was put forward by a number of prominent scientists, notably Lowell, that these were huge engineering works constructed by an intelligent race.  This view, though utterly false as is now known, inspired much science fiction. The thinning Barsoomian atmosphere is artificially replenished by an "atmosphere plant" on whose function all life on the planet is dependent.

The Martian year comprises 687 Martian days, each of which is 24 hours and 37 minutes long. (Burroughs presumably derived this from the figures published by Lowell, but erroneously substituted the number of 24-hour Earth days in the Martian year, rather than the number of 24.6-hour Martian days, which is only 669.) The days are hot (again known to be false) and the nights are cold, and there appears to be little variation in climate across the planet except at the poles.

Burroughs explained his ideas about the Martian environment in an article "A Dispatch on Mars" published in the London Daily Express in 1926. He assumed that Mars was formerly identical to the Earth; therefore a similar evolutionary development of fauna would have taken place. He referenced winds, snows, and marshes supposedly observed by astronomers, as evidence of an atmosphere, and that the wastes of the planet had been irrigated (probably referencing Lowell's "canals"), which suggested that an advanced civilization existed on the planet.

Races and culture
All Barsoomian races resemble Homo sapiens in most respects, except for being oviparous and having lifespans in excess of 1,000 years (though actual life expectancy is far shorter.) However, the Green Martians are much taller, have four arms, tusks, and antennae like ears. The traditional Martian lifespan of 1,000 is based on the customary pilgrimage down the River Iss, which is taken by virtually all Martians by that age, or those who feel tired of their long lives and expect to find a paradise at the end of their journey. None return from this pilgrimage, because it leads to almost certain death at the hands of ferocious creatures.

While the Martian females are egg-laying, Martians have inexplicably mammalian characteristics such as a navel and breasts. While they have skins of various colors, and their bodies differ in some cases from traditional humans, they are very similar to varieties of Earth humans and there is little examination of difference. There is only one spoken language across the entire planet, but a variety of writing systems.

All Martians are telepathic among one another, and also with domestic animals. Other telepathic abilities are demonstrated across the books. The Lotharians in Thuvia, Maid of Mars, are able to project images of warfare that can kill by suggestion. In The Warlord of Mars, the nations are described as bellicose and self-sufficient; but in The Gods of Mars inter-city state merchants are mentioned, and in Thuvia, Maid of Mars, towering staging posts for inter-city liners are also described.

Most of the cultures are dynasties or theocracies.

Red Martians
The Red Martians are the dominant culture on Barsoom. They are organized into a system of imperial city-states including Helium, Ptarth, and Zodanga, controlling the planetary canal system, as well as other more-isolated city-states in the hinterlands. The Red Martians are the interbred descendants of the ancient Yellow Martians, White Martians and Black Martians, remnants of which exist in isolated areas of the planet, particularly the poles. The Red Martians are said in A Princess of Mars to have been bred when the seas of Barsoom began to dry up, in hopes of creating a hardy race to survive in the new environment.

They are, like all the humanoid races of Mars, oviparous, i.e., their newborn hatch from eggs.

The Red Martians are highly civilized, respect the idea of private property, adhere to a code of honor and have a strong sense of fairness. Their culture is governed by law and is technologically advanced. They are capable of love and have families.

Green Martians

The Green Martians are  tall (males) and  tall (females), have two arms, two legs and two intermediary limbs that can be used as either arms or legs at will. Their eyes are mounted at the side of their heads and can move independently of each other in order to see in two directions at once. They are nomadic, warlike and barbaric, do not form families, have little concept of friendship or love and enjoy inflicting torture upon their victims. Their social structure is highly communal and rigidly hierarchical, consisting of various levels of chiefs, with the highest office of Jeddak obtained by mortal combat.

The Green Men are primitive, intellectually unadvanced, do not have any kind of art and are without a written language. While they manufacture edged weapons, any advanced technology they possess, such as 'radium pistols', is stolen from raids upon the Red Martians. They inhabit the ancient ruined cities left behind by civilizations which lived on Barsoom during a more advanced and hospitable era in the planet's history. They apparently arose from a biological experiment which went awry and as with all other Martians, they are an egg-laying species, concealing their eggs in incubators until hatching. Tars Tarkas, who befriends John Carter when he first arrives on Barsoom, is an unusual exception from the typical ruthless Green Martian, due to having known the love of his own mate and daughter.

In the novels, the Green Martians are often referred to by the names of their hordes, which in turn take their names from the abandoned cities they inhabit. Thus the followers of Tars Tarkas, based in the ruined ancient city of Thark, are known as "Tharks". Other hordes bear the names of Warhoon, Torquas, and Thurd.

Yellow Martians

Okarians
Yellow Martians are supposedly extinct, but in The Warlord of Mars they are found hiding in secret domed cities at the North Pole of Mars. At the time John Carter arrives on Barsoom, the Yellow Race is known only in old wives' tales and campfire stories.

The only means of entrance to the Okarians' city is through The Carrion Caves, which are every bit as unpleasant as the name suggests. Air travel over the barrier is discouraged through the use of a great magnetic pillar called "The Guardian of the North," which draws fliers of all sizes inexorably to their doom as they collide with the massive structure.

Their cities are domed hothouses which keep out the cold, but outdoors they favor orluk furs and boots. Physically they are large and strong, and the men usually wear bristling black beards.

White Martians

Orovars
The White Martians, known as 'Orovars', were rulers of Mars for 500,000 years, with an empire of sophisticated cities with advanced technology. They were white-skinned, with blond or auburn hair. They were once a seafaring race, but when the oceans began to dry up they began to cooperate with the Yellow and Black Martians to breed the Red Martians, foreseeing the need for hardy stock to cope with the emerging harsher environment. They became decadent and 'overcivilized'. At the beginning of the series they are believed to be extinct, but three remaining populations - the Orovars, Therns and Lotharians – are still living in secret and are discovered as the books progress.

Lotharians
The Lotharians are a remnant population of the original White Martians, which appear only in Thuvia, Maid of Mars. There are only 1000 of them remaining, all of them male. They are skilled in telepathy, able to project images that can kill, or provide sustenance. They live a reclusive existence in a remote area of Barsoom, debating philosophy amongst themselves.

Therns
Descendants of the original White Martians who live in a complex of caves and passages in the cliffs above the Valley Dor. This is the destination of the River Iss, on whose currents most Martians eventually travel, on a pilgrimage seeking final paradise, once tired of life or reaching 1000 years of age. The valley is actually populated by monsters who, overseen by Therns, attack all who enter the valley, killing and exsanguinating them for the Therns to cannibalize, only excepting those whom the directing Therns choose instead to enslave. They consider themselves a unique creation, different from other Martians. They maintain the Martian religion through a network of collaborators and spies across the planet. When they reach the age of 1000 years they make a pilgrimage to the Temple of Issus, unaware that they have been manipulated into doing so in order to be slaughtered by the Black Men of Mars in an analogous deception to that the Therns practice on other Martians.  They are also the repeated target of raids by the Black Martians to capture their females as slaves.  They are white-skinned (of a skin tone close enough to human Caucasians that John Carter was able to easily pose as one) and the males are bald but wear blond wigs.

Black Martians (First Born)
Legend suggests that the Black Martians are inhabitants of one of the moons of Mars, when in fact they live in an underground stronghold near the south pole of the planet, around the submartian Sea of Omean, below the Lost Sea of Korus, where they keep a large aerial navy. They call themselves the 'First-Born', believing themselves to be a unique creation among Martian races, and worship Issus, a woman who styles herself as the God of the Martian religion but is no such thing. They frequently raid the White Martian Therns, who maintain the false Martian religion, carrying off people as slaves. John Carter defeats their navy in The Gods of Mars.

Others

Kaldanes and RykorsThe Chessmen of Mars introduces the Kaldanes of the region Bantoom, whose form is almost all head but for six spiderlike legs and a pair of chelae, and whose racial goal is to evolve even further towards pure intellect and away from bodily existence. In order to function in the physical realm, they have bred the Rykors, a complementary species composed of a body similar to that of a perfect specimen of Red Martian but lacking a head; when the Kaldane places itself upon the shoulders of the Rykor, a bundle of tentacles connects with the Rykor's spinal cord, allowing the brain of the Kaldane to interface with the body of the Rykor. Should the Rykor become damaged or die, the Kaldane merely climbs upon another as an earthling might change a horse.

Kangaroo Men
A lesser people of Barsoom are the Kangaroo Men of Gooli, so called due to their large, kangaroo-like tails, ability to hop large distances and the rearing of their eggs in pouches. They are presented as a race of boastful, cowardly individuals. Their moral character is not highly developed; they are devout cowards and petty thieves, who value (aside from their lives) only a "treasure" consisting of pretty stones, sea shells, etc.

Hormads
In addition to the naturally occurring races of Barsoom, Burroughs described the Hormads, artificial men created by the scientist Ras Thavas as slaves, workers, warriors, etc. in giant vats at his laboratory in the Toonolian Marsh in Synthetic Men of Mars and "John Carter and the Giant of Mars". Although the Hormads were generally recognizable as humanoid, the process was far from perfect, and generated monstrosities ranging from the occasional misplaced nose or eyeball to "a great mass of living flesh with an eye somewhere and a single hand."

Technology
When Burroughs wrote the first volume of the Barsoom series, aviation and radio technology was in its infancy and radioactivity was a fledgling science. Despite this, the series includes a range of technological developments including radium munitions, battles between fleets of aircraft, devices similar to faxes and televisions, genetic manipulation, elements of terraforming and other ideas.  One notable device mentioned is the "directional compass"; this may be believed to be the precursor to the now-common "global positioning system", or GPS for short.

Fliers
The Red Martians have flying machines, both civilian transports and fleets of heavily armed war craft. These stay aloft through some form of anti-gravity, which Burroughs explains as relating to the rays of the Sun. Fliers travel at approximately  (450 Martian Haads per hour).

In Thuvia, Maid of Mars, John Carter's son Carthoris invents what appears to be a partial precursor of the autopilot (several decades before it became a reality). The device, built upon existing Martian compass technology, allows the pilot to reach any programmed destination, having only to keep the craft pointed in the set direction. Upon arrival, the device automatically lowers the craft to the surface. He also includes a kind of collision detector, which uses radium rays to detect any obstacle and automatically steer the craft elsewhere until the obstacle is no longer detected. This device works in principle almost identically to the backscatter radiation detector used to fire the braking rockets on the Soyuz space capsule. In Swords of Mars a flier with some kind of mechanical brain is introduced. Controlled by thought, it can be remote-controlled in flight, or instructed to travel to any destination.

Weapons
Firearms are common, and use 'Radium' bullets, which explode when exposed to sunlight. Some weapons are specific to races or inventors. The mysterious Yellow Martians, who live in secret glass-domed cities at the poles and appear in The Warlord of Mars have a form of magnet which allows them to attract flying craft and cause them to crash. Scientist Phor Tak, who appears in A Fighting Man of Mars, has developed a disintegrator ray, and also a paste which renders vehicles such as fliers impervious to its effects. He also develops a missile which seeks out craft protected in this fashion, and a means of rendering fliers invisible which becomes a key plot device in the novel. However, while advanced weapons are available, most Martians seem to prefer melee combat — mostly with swords — and their level of skill is highly impressive.  Warriors often are armed with four weapons (in descending order, pistol, long-sword, short sword and dagger) and it is considered unchivalrous to defend with any weapon but the one used in an attack (or a lesser one.) While technically it would be easy to use firearms to kill an opponent armed with a sword, such conduct is socially unacceptable and (except for one abortive attempt by the assassin Uldak in Swords of Mars) even the villains in Barsoom books never resort to it.

Atmosphere plant
There are many technological wonders in the novels, some colossal works of engineering. The failing air of the dying planet is maintained by an atmosphere plant, and the restoration of this is a plot component of A Princess of Mars. It is described as being  across with walls  in depth, and telepathically operated entrance doors of  steel.

Medicine and biology
Martian medicine is generally greatly in advance of that on Earth. Various "ointments" and "salves," particularly as ascribed to the Green Martian women, are capable of healing all but instantly deadly wounds in a matter of hours—as first seen in A Princess of Mars. In The Master Mind of Mars aging genius Ras Thavas has perfected the means of transplanting organs, limbs and brains, which during his experiments he swaps between animals and humanoids, men and women and young and old. Later, in Synthetic Men of Mars, he discovers the secret of life, and creates an army of artificial servants and warriors grown in giant vats filled with organic tissue. They frequently emerge deformed, are volatile and are difficult to control, later threatening to take over the planet.

Clothing
The Martians wear no clothing other than jewelry and leather harnesses, which are designed to hold everything from the weaponry of a warrior to pouches containing toiletries and other useful items; the only instances where Barsoomians habitually wear clothing is for need of warmth, such as for travel in the northern polar regions described in The Warlord of Mars.

This preference for near-nudity provides a stimulating subject for illustrators of the stories, though art for many mass-market editions of the books feature Carter and native Barsoomians wearing loincloths and other minimal coverings, or use strategically placed shadows and such to cover genitalia and female breasts.

Fauna
It appears that most of Burrough's Martian creatures are roughly equivalent to those found on Earth, though most seem to have multiple legs (usually a total of six limbs, but sometimes as many as ten) and all are egg-laying.

"Insects", "reptiles" and "birds"
Sith: A giant, venomous hornet-like insect endemic to the Kaolian Forest.
 Reptiles: Are described as repulsive and usually poisonous, and include
Darseen, a chameleon-like reptile.
Silian, an Antarctic sea-monster found in the Lost Sea of Korus.
 Birds: Burroughs tells us that Martian birds are brilliantly plumed, but the only species actually described is the enormous Malagor, native to the Great Toonolian Marshes.

"Mammals"

The martian mammalian equivalents all have fur, and both domestic and wild varieties are described by Burroughs.

Domesticated
Sorak: A small six-legged creature, equivalent to a cat.
 Calot: A large dog-like creature with a frog-like mouth, and three rows of teeth and ten short legs. John Carter has his own calot, named Woola, who is his faithful companion during most of A Princess of Mars and The Warlord of Mars.
Thoat: A Martian horse. It has four legs on each side of its body and a wide, flat tail, which is wider at the apex than at the base and which is extended while running. The Greater Thoat is used as a mount by the Green Martians and stands about  high at the shoulder; the Lesser Thoat bred by the Red Martians is closer to Earth horses in size. The Thoat is described as a slate-colored animal, with a white underside and yellow lower legs and feet.
Zitidar: A draft animal, described as being similar to mastodons.

Wild

Apt: A large white-furred arctic creature with six limbs, four being legs, which give it rapid speed, and two being arms with hairless hands, with which it grasps prey. It has tusks growing from its lower jawbone, and large faceted, insect-like eyes. Appears in The Warlord of Mars.
Banth: A Barsoomian "lion". It hunts the hills surrounding the dead seas of Barsoom. It has a long, sleek body, with ten legs, and large jaws equipped with several rows of sharp fangs in a mouth which extends back almost to its small ears. It is mostly hairless, except for a thick mane around the neck. It has large, protruding green eyes.
Ulsio: A kind of Barsoomian "rat", described as a dog-sized burrower.
White Ape: Huge and ferocious, semi-intelligent gorilla-like creatures with an extra set of arms, which first appear in A Princess of Mars.

Other
Rykors are headless but otherwise human-like creatures bred by the Kaldanes, appearing only in The Chessmen of Mars.
Plant Men: Monsters found in the Valley Dor. They are between  in height when upright, with hairless bodies similar in form to humans, excepting broad flat feet which are  in length and a  tail, which tapers from a round profile to a flat blade shape at the tip. They also have short, sinuous arms similar to elephant trunks, ending with taloned hands with mouths set in the palms. It also attacks and feeds upon Martian Pilgrims, who travel to the Valley Dor expecting to find final paradise. Their faces are without mouths, with a nose like an open wound, a single white eye surrounded by a white band, and black hair 10 to 12 inches long, each strand similar in thickness to an earthworm. They appear in The Gods of Mars. The Plant Men have a mouth in the palm of each hand, with which they feed on tender vegetation (which they shear with their razor-sharp talons) or on the blood of their victims. After "the defiling blood of life has been drawn" from a human by the Plant Men, the flesh may be eaten by the Holy Therns, another Barsoomian race.
Orluk: An Arctic predator with a black and yellow striped coat, whose legs are not described.

Themes

American frontier
Barsoom might be seen as a kind of Martian Wild West. John Carter is himself an adventuring frontiersman. When he arrives on Barsoom he first compares it to the landscape of Arizona which he has left behind. He discovers a savage, frontier world where the civilized Red Martians are kept invigorated as a race by repelling the constant attacks of the Green Martians, a possible equivalent of Wild West ideals. Indeed, the Green Martians are a barbaric, nomadic, tribal culture with many parallels to stereotypes of American Indians. The desire to return to the frontier became common in the early 20th century America. As the United States become more urbanized, the world of the 19th century frontier America became romanticized as a lost world of freedom and noble qualities.

Race
Race is a constant theme in the Barsoom novels and the world is clearly divided along racial lines. Red, Green, White, Black, and Yellow races all appear across the novels, each with particular traits and qualities which seem to define the characters of the individuals. In this respect, Burroughs' concept of race, as depicted in the novels, is more like a division between species. The Red and Green Martians are almost complete opposites of one another, with the Red Martians being civilized, lawful, capable of love and forming families, and the Green Martians being savage, cruel, tribal and without families or the ability to form romantic relationships. Yet, friendship between individuals of different nations and races is a frequent topic driving the stories.

Religious deception
The Barsoom series features a number of incidents of religious deception, or the use of superstition by those in power to control and manipulate others. Burroughs is particularly concerned about the hypocrisy of religious leaders. This is first established in A Princess of Mars, but becomes particularly apparent in the sequel, The Gods of Mars. Upon reaching 1,000 years of age almost all Martians undertake a pilgrimage on the River Iss, expecting to find a valley of mystical paradise; what they find is in fact a deathtrap, populated by ferocious creatures and overseen by a race of cruel, cannibal priests known as Therns, who perpetuate the Martian religion through a network of spies across the planet.

John Carter's battle to track down the remnants of the Therns and their masters continues in the sequel, The Warlord of Mars. More deceitful priests in a nation controlled by such appear in The Master Mind of Mars, on this occasion manipulating a temple idol to control followers.

Burroughs continued this theme in his many Tarzan novels. Burroughs was not anti-religious; however, he was concerned about followers placing their trust in religions and being abused and exploited, and saw this as a common feature of organized religion.

Excessive intellectualism
While Burroughs is generally seen as a writer who produced work of limited philosophical sophistication, he wrote two Barsoom novels which appear to explore or parody the limits of excessive intellectual development at the expense of bodily or physical existence. The first was Thuvia, Maid of Mars, in which Thuvia and Carthoris discover a remnant of ancient White Martian civilization, the Lotharians. The Lotharians have mostly died out, but maintain the illusion of a functioning society through powerful telepathic projections. They have formed two factions which appear to portray the excesses of pointless intellectual debate. One faction, the realists, believes in imagining meals to provide sustenance; another, the etherealists, believes in surviving without eating.The Chessmen of Mars is the second example of this trend. The Kaldanes have sacrificed their bodies to become pure brain, but although they can interface with Rykor bodies, their ability to function, compared with normal people of integrated mind and body, is ineffectual and clumsy. The Kaldanes, though highly intelligent, are ugly, ineffectual creatures when not interfaced with a Rykor body. Tara of Helium compares them to effete intellectuals from her home city, with a self-important sense of superiority; and Gahan of Gathol muses that it might be better to find a balance between the intellect and bodily passions.

Paradox of "Superiority"
Some of Barsoom's people, especially the Therns and First-Born, hold themselves as "superior" to the "lesser order" people on Barsoom. A paradox is established in that the Therns and First-Born, though they hold themselves in such high esteem, nonetheless are dependent on these lesser orders for their sustenance, labor, and goods. The Therns and First-Born are "non-productive" people and do not produce anything or invent, as such labor is seen as beneath them. This is punctuated by the fact that the Therns and First-Born are obliged to create strongholds in the south polar regions, to insulate themselves from the remainder of the planet dominated primarily by red and green Martians. A particular ironic twist is introduced by the fact that the white Therns think that they control and manipulate the entire planet, when they are in turn unknowingly exploited by the black First-Born.

Antecedents and influences on Burroughs

Scientific inspiration

Burroughs' concept of a dying Mars and the Martian canals follows the theories of Lowell and his predecessor Giovanni Schiaparelli. In 1878, Italian astronomer Giovanni Virginio Schiaparelli observed geological features on Mars which he called canali (Italian: "channels"). This was mistranslated into the English as "canals" which, being artificial watercourses, fueled the belief that there was some sort of intelligent extraterrestrial life on the planet. This further influenced American astronomer Percival Lowell.

In 1895 Lowell published a book titled Mars which speculated about an arid, dying landscape, whose inhabitants had been forced to build canals thousands of miles long to bring water from the polar caps (now known to be mostly frozen carbon dioxide or "dry ice") to irrigate the remaining arable land. Lowell followed with Mars and Its Canals (1906) and Mars as an Abode of Life (1908). These books formed prominent scientific ideas about the conditions on the red planet in the early years of the 20th century. Burroughs does not seem to have based his vision of Mars on precise reading of Lowell's theories, however, as a number of errors in his books suggest he got most of his information from newspaper articles and other popular accounts of Lowell's Mars.

The concept of canals with flowing water and a world where life was possible were later proved erroneous by more accurate observation of the planet. Later landings by American probes such as the two Viking missions found a dead world too cold (and with far too thin an atmosphere) for water to exist in its fluid state.

Previous Mars fiction

The first science fiction to be set on Mars may be Across the Zodiac, by Percy Greg, published in 1880, which concerned a civil war on Mars. Another Mars novel, dealing with benevolent Martians coming to Earth was published in 1897 by Kurd Lasswitz, Auf Zwei Planeten. It was not translated until 1971, and was thus unlikely to have influenced Burroughs, although it did depict a Mars influenced by the ideas of Percival Lowell. Other examples are Mr. Stranger's Sealed Packet (1889), which took place on Mars; Gustavus W. Popes's Journey to Mars (1894); and Ellsworth Douglas's Pharaoh's Broker, in which the protagonist encounters an Egyptian civilization on Mars which, while parallel to that of the Earth, has evolved somehow independently.

H.G. Wells' novel, The War of the Worlds, most definitely influenced by Lowell and published in 1898, did however create the precedent for a number of enduring Martian tropes in science fiction writing. These include Mars being an ancient world, nearing the end of its life; being the home of a superior civilization, capable of advanced feats of science and engineering; and a source of invasion forces, keen to conquer the Earth. The first two tropes were prominent in Burroughs' Barsoom series. Burroughs, however, claimed never to have read any of H.G. Wells' books. Lowell was probably the greater direct influence on Burroughs.

Richard A. Lupoff claimed that Burroughs was influenced in writing his Martian stories by Edwin Lester Arnold's earlier novel Lieut. Gullivar Jones: His Vacation (1905) (later retitled Gulliver of Mars). Gullivar Jones, who travels to Mars by flying carpet rather than via astral projection, encounters a civilization with similarities to those found on Barsoom, rescues a Martian Princess, and even undertakes a voyage down a river similar to the Iss in The Gods of Mars. Lupoff also suggested that Burroughs derived characteristics of his main protagonist John Carter from Phra, hero of Arnold's The Wonderful Adventures of Phra the Phoenician (1890), who is also a swashbuckling adventurer and master swordsman for whom death is no obstacle. Lupoff's theories were disputed by numerous scholars of Burroughs' work; Lupoff countered, claiming that many of Burroughs' stories had antecedents in previous works and that this was not unusual for writers.

Burroughs' influence

Public figures

Burroughs' Barsoom series was popular with American readers, public figures, and scientists who grew up reading the novels and helped inspire public support for the US space program.

Notable fans of the Barsoom series include Carl Sagan, Terry Wilcutt, Jane Goodall, Michael Crichton, Arthur C. Clarke, and Ronald Reagan. Author Edmund Morris wrote in his biography Dutch: A Memoir of Ronald Reagan that A Princess of Mars was Reagan's favorite childhood novel.

Scientist Carl Sagan read the books as a young boy, and they continued to affect his imagination into his adult years. Sagan remembered Barsoom as a "world of ruined cities, planet-girdling canals, immense pumping stations – a feudal technological society". For two decades, a map of the planet as imagined by Burroughs, hung in the hallway outside Sagan's office in Cornell University. The author so influenced real exploration of Mars that an impact crater was named after him.

Early science-fiction writers Ray Bradbury and Arthur C. Clarke were both inspired by the Barsoom books in their youth, with them serving as an inspiration for Bradbury's The Martian Chronicles (1950), in which he used the concept of a dying Mars. Writer Robert A. Heinlein also wrote fiction inspired by Burroughs' Barsoom series, and for many others the Barsoom series helped to establish Mars as an adventurous, enticing destination for the imagination.

Games
The Warriors of Mars rules for miniature warfare by Gary Gygax and Brian Blume were controversial, and a legal dispute with the owners of the rights to the Barsoom series led to withdrawal of this title from the market.

Other games include the role-playing game published by Heritage Models, Inc. in 1978 and SPI's (Simulations Publications, Inc.) boardgame John Carter: Warlord of Mars published in 1979.Eclipse Phase features rural Martian nomads called Barsoomians.

Novels and short stories
Numerous novels and series by others were inspired by Burroughs' Mars books: the Radio Planet trilogy of Ralph Milne Farley; the Mars and Venus novels of Otis Adelbert Kline; Almuric by Robert E. Howard; Warrior of Llarn and Thief of Llarn by Gardner Fox; Tarzan on Mars by John Bloodstone; the Michael Kane trilogy of Michael Moorcock; The Dream-Quest of Unknown Kadath, Through the Gates of the Silver Key by H. P. Lovecraft, the Gor series of John Norman; the Callisto series and Green Star series of Lin Carter; The Goddess of Ganymede and Pursuit on Ganymede by Mike Resnick; and the Dray Prescot series of Alan Burt Akers (Kenneth Bulmer). In addition, Leigh Brackett, Ray Bradbury, Andre Norton, Marion Zimmer Bradley, and Alan Dean Foster show Burroughs' influence in their development of alien cultures and worlds.

Robert A. Heinlein's novels Glory Road and The Number of the Beast, and Alan Moore's graphic novels of Allan and the Sundered Veil and The League of Extraordinary Gentlemen, Volume II directly reference Barsoom.

In Philip José Farmer's World of Tiers series (1965–1993) Kickaha, the series' adventurer protagonist, asks his friend The Creator of Universes to create for him a Barsoom. The latter agrees only to make an empty world, since "It would go too far for me to create all these fabulous creatures only for you to amuse yourself by running your sword through them." Kickaha visits from time to time the empty Barsoom, complete with beautiful palaces in which nobody ever lived, but goes away frustrated.

L. Sprague de Camp's story "Sir Harold of Zodanga" recasts and rationalizes Barsoom as a parallel world visited by his dimension-hopping hero Harold Shea. De Camp accounts for Burroughs' departures from physics or logic by portraying both Burroughs and Carter as having a tendency to exaggerate in their storytelling, and Barsoomian technology as less advanced than usually presented.

In 1989 Larry Niven and Steven Barnes published "The Barsoom Project", the second in the "Dream Park" series, where a Martian terraforming and colonization project is named after the Barsoom books.

The 2008 novel In the Courts of the Crimson Kings by S.F. writer S. M. Stirling is an alternate telling of the Princess of Mars story but this time the princess is a very powerful character indeed.

Richard Corben's Den series also appears to be inspired by the Barsoom series. It features a hero, Den, who mysteriously arrives naked on a (largely) desert planet where he becomes a great warrior and where the humanoids wear no clothes. Many of the creatures resemble the description of the white apes of the Gods of Mars. Like John Carter, he also receives great physical prowess from arriving in Neverwhere, although Carter's prowess stems from gravity, whereas Den undergoes a complete physical transformation.

In A Wizard of Mars by Diane Duane, the main character Kit is a major fan of the Barsoom series and a long dormant wizard artifact recreates Barsoom as Kit imagines it to communicate with him.

"Mars: The Home Front", a short story by George Alec Effinger, published in War of the Worlds: Global Dispatches, is a crossover between the Barsoom series and H. G. Wells' The War of the Worlds – with Wells' Martians being depicted as a malevolent additional Barsoomian race and John Carter fighting them to help foil their invasion of Earth.

In the first chapters of Gore Vidal's novel Washington, D.C., the character Peter Sanford – sixteen at the outset of the plot – indulges in vivid and detailed fantasies of being John Carter, and adds explicit erotic scenes not appearing in the original Burroughs books.

In Karl Schroeder's novel Lockstep, set over 14,000 years in the future, Mars has been terraformed and is renamed Barsoom, with its human inhabitants no longer remembering that the world was ever named Mars. This Barsoom is covered in canals and ruins from the civilizations of previous millennia, and is also mentioned to be inhabited by genetically engineered Tharks. The ruler of Barsoom is also the son of a man named Carter.

Poetry
The science fiction poems in Oscar Hurtado's book La Ciudad Muerta de Korad (The Dead City of Korad, in Spanish) are full of intertextualities with the Barsoom series, as well as with the Sherlock Holmes novels by Arthur Conan Doyle, the Iliad, children folk tales, and other references.The Dead City of Korad was published in 1964 and marks the beginning of the science fiction genre in Cuba.

Film and television
 Avatar: In interviews, James Cameron has invoked Burroughs as one of the primary inspirations behind his 2009 space adventure.
 Babylon 5: In this science fiction television series, Amanda Carter – a Martian citizen and advocate of Mars' independence from Earth – is revealed to have had a grandfather named John who was a pioneer colonist on Mars. This has been confirmed by the series creator J. Michael Straczynski as a reference made by the episode writer Larry DiTillio to John Carter of Mars.

Adaptations

Comic strips

John Carter of Mars (1941–1943)
With the Tarzan comic strip a popular success, newspapers began a comic strip adaptation of A Princess of Mars drawn by Edgar Rice Burroughs' son, John Coleman Burroughs. Never as popular as Tarzan, the strip ran in only four Sunday newspapers, from December 7, 1941, to March 28, 1943, for a total of 73 installments.

The Martian (1958–1959)
Fifteen years later, the British tabloid paper Sunday Sun ran a newspaper strip also based on the first Barsoom novel titled The Martian. This adaptation was written by D. R. Morton and drawn by Robert Forest, the strip ran as a weekly serial from October 25, 1958, to May 23, 1959, for a total of 31 installments.

Tarzan (1994–1995)
From October 16, 1994, to August 13, 1995, writer Don Kraar and artist Gray Morrow set an arc first in Pellucidar and then on Barsoom featuring Tarzan, David Innes, and John Carter in a crossover adventure through their respective worlds. This storyline was the last Sunday strip installment to feature Carter, Barsoom and the worlds outside of Tarzan.

Comic booksThe Funnies (Dell Comics): This comics anthology included a John Carter of Mars serial drawn by John Coleman Burroughs, which ran for 23 installments through issues #30–56 (April 1939 – June 1941) respectively; a story was intended for issue 57 (July 1941) but was never apparently published.John Carter of Mars (Dell Comics): Dell published three comic issues in 1952, adapting the first three Barsoom books, drawn by Jesse Marsh, who was the Dell Tarzan artist at the time. They were Four Color issues #375, 437, and 488 respectively. They were later reprinted by the successor of Dell, Gold Key Comics as John Carter of Mars #1–3.ABC Magazine, Czechoslovakia: The first four Barsoom novels were printed as two comic book series (51 pages altogether) from 1970 to 1972 (Written by Vlastislav Toman, with painters Jiří Veškrna and Milan Ressel.) They were reprinted in 2001 in the comic book Velká Kniha Komiksů I.John Carter in Tarzan of the Apes (DC Comics): John Carter of Mars was published as a backup feature through issues #207–209 (April—June 1972) in the Tarzan series, after which it was moved to Weird Worlds, sharing main feature status alongside an adaptation of Burroughs' Pellucidar stories in issues #1–7 (September 1972 – October 1973); it again became a backup feature in Tarzan Family #62–64 (April – August 1976). A non-John Carter Barsoom story, titled "Amazon of Barsoom", appeared two issues earlier in Tarzan Family #60 (December 1975).John Carter, Warlord of Mars (Marvel Comics): This series began in 1977 and lasted for 28 issues (and saw three annuals published).The League of Extraordinary Gentlemen (DC Comics): John Carter made a notable cameo in the second volume of the series written by Alan Moore. Along with other literary Martian characters (including Gullivar Jones and the séroni), he leads a campaign against the Martians from The War of the Worlds.Tarzan/John Carter: Warlords of Mars (Dark Horse Comics): Running from January to June 1996, this limited series was the first standalone comic book crossover with Tarzan.Warlord of Mars (Dynamite Entertainment): Starting in October 2010, Dynamite began publishing an ongoing series entitled Warlord of Mars. The first two issues served as a prelude story, issues 3–9 adapted A Princess of Mars, and issues 10–12 were an original story.Warlord of Mars: Dejah Thoris (Dynamite Entertainment): Starting in March 2011, it is set 400 years before A Princess of Mars and focuses on Dejah Thoris, her first suitor, and her role in the rise to power of the Kingdom of Helium.Warlord of Mars: Fall of Barsoom (Dynamite Entertainment): Running from July 27, 2011, to January 25, 2012, it is set 100,000 years before A Princess of Mars and focuses on the attempt of two Orovars to save Mars as the seas dry up and the atmosphere becomes thin.John Carter: A Princess of Mars (Marvel Comics): Running from September 14, 2011, to January 18, 2012John Carter: World of Mars (Marvel Comics): Running from October 12, 2011, to January 18, 2012, this limited series serves as a prequel to the 2012 Disney film.Warriors of Mars (Dynamite Entertainment): Running from February 1, 2012, to October 24, 2012, this limited series deals with John Carter's encounter with Lt. Gullivar Jones, another earthman whose journey to the Red planet predated his own.John Carter: The Gods of Mars (Marvel Comics); Running from March 21, 2012, to July 25, 2012Dejah Thoris and the White Apes of Mars (Dynamite Entertainment): Running from April 4, 2012, to July 25, 2015, Dejah Thoris and her party are stranded on the way to an archeological dig at an ancient battle site at the 'face' of Mars. They take shelter in a dead, ancient city infested with killer white apes.A Princess of Mars — A Graphic Novel (Sterling Publishing): Published from May 28, 2012, this faithful adaptation is a part of Sterling's "Illustrated Classics" series which produces graphic novel adaptations of classic literature and was written by Ian Edginton and illustrated by I. N. J. Culbard, with a total of 136 pages. ( / )Dejah Thoris and the Green Men of Mars (Dynamite Entertainment): Running from February 20, 2013, to March 26, 2014Lords of Mars (Dynamite Entertainment): Running from August 7, 2013, to January 8, 2014, this limited series was the second standalone comic book crossover with Tarzan, after Dark Horse's Warlords of Mars.Dejah of Mars (Dynamite Entertainment): Running from May 28, 2014, to September 3, 2014Swords of Sorrow (Dynamite Entertainment): Running from May 6, 2015, to October 14, 2015, this limited series was a crossover event storyline uniting the pre-existing fictional heroines Dynamite had the rights to at the time, including Vampirella, Barbarella, Red Sonja, Kato, Jungle Girl, Lady Zorro, Eva, Miss Fury, Esmeralda Aguilar, Miss Masque and Irene Alder, of which Dejah Thoris was one of many.Swords of Sorrow: Dejah Thoris & Irene Adler (Dynamite Entertainment): Running from June 17, 2015, to August 5, 2015, a tie-in to the crossover event comic Swords of Sorrow.John Carter: Warlord of Mars (Dynamite Entertainment): Running from November 5, 2014, to December 23, 2015John Carter: The End (Dynamite Entertainment): Running from February 8, 2017, to July 14, 2017The Greatest Adventure (Dynamite Entertainment): Running from April 19, 2017, to February 7, 2018, this limited series was a crossover story uniting John Carter, Dejah Thoris, Tarzan, David Innes, Carson Napier and Jason Gridley in a wild chase through many locations from Africa, Caspak, Pellucidar, Barsoom and Amtor as the heroes journey to obtain the "Eye of Judgment", an ancient gemstone possessed by the villain Rokoff to power a doomsday device, capable of destroying everything in the universe.Vampirella/Dejah Thoris (Dynamite Entertainment): Running from September 26, 2018, to February 13, 2019, a crossover with Vampirella.Barbarella/Dejah Thoris (Dynamite Entertainment): Running from January 9, 2019, to June 19, 2019, a crossover with Barbarella.Carson of Venus/Warlord of Mars (American Mythology Productions): Published from June 2019, a standalone crossover with Carson Napier of the Amtor series.Warlords of Mars Attacks (Dynamite Entertainment): Running from June 19, 2019, to October 30, 2019, a crossover with Mars Attacks.Dejah Thoris vs. John Carter of Mars (Dynamite Entertainment): Running from July 21, 2021, to December 22, 2021John Carter of Mars (Dynamite Entertainment): Running from April 20, 2022, to August 31, 2022Dejah Thoris: Fairy Tales (Dynamite Entertainment): Published from August 24, 2022

FilmPrincess of Mars was a 2009 direct-to-video film produced by The Asylum and starring Antonio Sabato Jr. as John Carter and Traci Lords as Dejah Thoris. This adaptation starts with John Carter as a wounded present-day sniper in Afghanistan who is teleported to another world as part of a government experiment.John Carter, released on March 9, 2012, was a big-budget but critically mediocre and financially unsuccessful live-action film by The Walt Disney Company, directed by Andrew Stanton and starring Taylor Kitsch as John Carter and Lynn Collins as Dejah Thoris.

See also
 Jetan, a game invented by Burroughs and described in The Chessmen of Mars''
 Pellucidar

References

External links

 Maps of Barsoom

Book series introduced in 1917
Fictional elements introduced in 1912
Edgar Rice Burroughs locations
Fictional terrestrial planets

Barsoom


Arrival is a 2016 American science fiction drama film directed by Denis Villeneuve and adapted by Eric Heisserer, who conceived the project as a spec script based on the 1998 short story "Story of Your Life" by Ted Chiang. The film stars Amy Adams as Louise Banks, a linguist enlisted by the United States Army to discover how to communicate with extraterrestrials who have arrived on Earth, before tensions lead to war. Jeremy Renner, Forest Whitaker, Michael Stuhlbarg, and Tzi Ma appear in supporting roles.

Arrival had its world premiere at the Venice Film Festival on September 1, 2016, and was released theatrically in the United States by Paramount Pictures on November 11, 2016. It grossed $203 million worldwide and received critical acclaim, with particular praise for Adams's performance, Villeneuve's direction, and the exploration of communication with extraterrestrial intelligence. Considered one of the best films of 2016, Arrival appeared on numerous critics' year-end lists and was selected by the American Film Institute as one of ten "Movies of the Year".

It received eight nominations at the 89th Academy Awards, including Best Picture, Best Director, Best Cinematography, Best Adapted Screenplay, and won Best Sound Editing. For her performance, Adams received nominations for a BAFTA, SAG, Critics' Choice, and at the 74th Golden Globe Awards, Adams was nominated for the Golden Globe Award for Best Actress and Jóhann Jóhannsson was nominated for the Golden Globe Award for Best Original Score. The film was awarded the Ray Bradbury Award for Outstanding Dramatic Presentation and the Hugo Award for Best Dramatic Presentation in 2017. The score by Jóhannsson was nominated for Best Score Soundtrack for Visual Media at the 60th Grammy Awards.

Plot
Linguist Louise Banks's daughter Hannah dies at the age of twelve from an incurable illness.

Twelve extraterrestrial spacecraft hover over various locations around the Earth. In the ensuing widespread panic, affected nations send military and scientific experts to monitor and study them.  In the United States, US Army Colonel Weber recruits Banks and physicist Ian Donnelly to study the craft above Montana. On board, Banks and Donnelly make contact with two cephalopod-like, seven-limbed aliens, whom they call "heptapods"; Donnelly nicknames them Abbott and Costello. Banks and Donnelly research the complex written language of the aliens, consisting of palindromic phrases written with circular symbols, and share the results with other nations. As Banks studies the language, she starts to have flashback-like visions of her daughter.

When Banks is able to establish sufficient shared vocabulary to ask why the aliens have come, they answer with a statement that could be translated as "offer weapon". China interprets this as "use weapon", prompting them to break off communications, and other nations follow. Banks argues that the symbol interpreted as "weapon" can be more abstractly related to the concepts of "means" or "tool"; China's translation likely results from interacting with the aliens using mahjong, a highly competitive game.

Rogue soldiers plant a bomb in the Montana craft. Unaware, Banks and Donnelly re-enter the alien vessel, and the aliens give them a more complex message. Just before the bomb explodes, one of the aliens ejects Donnelly and Banks from the vessel, knocking them unconscious. When they wake, the alien craft has moved beyond reach and the US military is preparing to evacuate in case of retaliation.

China's General Shang issues an ultimatum to his local alien craft, demanding that it leave China within 24 hours. Russia, Pakistan, and Sudan follow suit; communications between the international research teams are terminated as worldwide panic sets in.

Donnelly discovers that the symbol for time is present throughout the message and that the writing occupies exactly one-twelfth of the 3D space into which it is projected. Banks suggests that the full message is split among the twelve craft and that the aliens want all the nations to share what they learn.

Banks goes alone to the Montana craft, which sends down a transport pod. Abbott has been mortally injured as a result of the explosion. Costello explains that they have come to help humanity, for in 3,000 years they will need humanity's help in return. Banks realizes the "weapon" is their language. Learning the language alters humans' linear perception of time, allowing them to experience memories of future events. Banks's visions of her daughter are revealed to be premonitions; her daughter will not be born until sometime in the future.

Banks returns to the camp as it is being evacuated and tells Donnelly that the aliens' language is the "tool" that was meant by the word "weapon". She has a premonition of a United Nations event celebrating newfound unity, following the alien arrival, in which Shang thanks her for persuading him to stop the attack when she called his private number and recited his wife's dying words. He then shows her his private number.

In the present, Banks takes CIA agent Halpern's satellite phone from a table and calls Shang's private number to recite the words. The Chinese announce that they are standing down and releasing their twelfth of the message. The other countries follow suit, and the twelve spacecraft depart.

Based on what she has learned, she writes and publishes a book called "The Universal Language", a guide to the heptapod language, which will eventually teach humanity to perceive time the same way as the heptapods.

During the evacuation, Donnelly expresses his love for Banks. They talk about life choices and whether he would change them if he could see his life from beginning to end. Banks knows that she will agree to have a child with him despite knowing their fate: that Hannah will die from an incurable disease and Donnelly will leave them both after she reveals that she knew this.

Cast

Production

Development and pre-production

Arrival is based on the Nebula-winning science fiction novella "Story of Your Life" by Ted Chiang, written in 1998. The novella involves Earth's first communication with heptapods who speak in a cryptic language. Screenwriter Eric Heisserer had been introduced to the story through another of Chiang's stories, "Understand", and had begun reading through Chiang's collected works when "Story of Your Life" had a "profound emotional effect" on him. As a result, he decided to try to adapt the story into a film script as he wanted to share it with a wider audience. After writing an initial spec script, Heisserer pitched it to production companies for several years without receiving any interest and nearly gave up on the project. Heisserer believes it was not until he had successfully completed and produced 2013's Hours that others took interest in his work, his having proved himself capable. Eventually, Dan Levine and Dan Cohen of 21 Laps Entertainment expressed interest in Heisserer's script. Shawn Levy of 21 Laps said they had become aware of "Story of Your Life" around 2011 and considered it a powerful work; when they learned of Heisserer's script adaptation, they started working closely with him, helping him refine the script before they began seeking a director and distribution studio.

One of the directors that 21 Laps approached was Denis Villeneuve. Villeneuve had wanted to make a science fiction film for some time, although he "never found the right thing". Cohen and Levine, however, introduced Villeneuve to the novella, which the director immediately took to, although his work on Prisoners meant that he did not have the time to properly adapt it into a screenplay with Heisserer. Heisserer completed a first draft, which Villeneuve and Heisserer reworked into the final script. Villeneuve changed the title, as he felt the original sounded like a romantic comedy and that the script had become very different from the short story. While Villeneuve went through "hundreds" of possible titles, Arrival was the first one his team of producers and writers had suggested.

Heisserer had made several changes from "Story of Your Life" between writing his original screenplays and the final script, the main one being that the heptapods actually arrived on Earth in a type of first contact situation, as he felt this helped to create the tension and conflict needed for a film. Heisserer said that earlier versions of the script had a different ending: the gift from the heptapods was to have been "blueprints to an interstellar ship, like an ark of sorts", to enable humanity to help them in 3,000 years. But after the release of Interstellar in 2014, Heisserer and Villeneuve agreed that this would not work, and decided that the heptapods' gift would be what was "there in front of us … the power of their language".

Amy Adams entered negotiations to star in the film in April 2014, and would be confirmed by the time Jeremy Renner joined the film in March 2015. Forest Whitaker signed on in April, with Michael Stuhlbarg joining soon after in June. Adams, who was playing a linguistics professor in the film, consulted with linguist Jessica Coon to prepare for her role.

Filming

Principal photography lasted for 56 days, beginning on June 7, 2015, after Renner had fulfilled his obligations to Captain America: Civil War. Filming was done mainly in and around Montreal, Quebec, with Saint-Fabien serving as Montana. The team took some time to find the right site to represent the landing of the spacecraft because producers wanted to avoid a mountainous site that might dwarf the scale of the ship, but thought that a barren location would be clichéd. Most of the filming that did not involve the exterior of a ship was done indoors on sound stages, although a real house located in Chemin de l'Île, Vaudreuil-Dorion, was used as Banks's home. The scenes of the university where Banks teaches were shot at HEC Montréal.
Bradford Young was sought out by Villeneuve as he was looking for a cinematographer with a sensibility toward natural lighting. Said Villeneuve: "I wanted the movie to have strong roots in realism. I wanted a cinematographer who would not be afraid to deal with intimacy. It's a very specific sensibility that I felt in Bradford's previous work." Color timing was used as a means of matching Louise's state of mind at a given moment. Young stated "I went for cooler colors when I wanted Amy to feel worn down. We tried to pull back on that a little bit, but then Denis stopped me in the [color timing] and told me not to be so concerned about skin tone and let her be pasty, let her exist in that melancholy space, let us feel that visually." When discussing the film with Villeneuve, Young described the director's goal of making a "dirty" science fiction film, by making the look of the film more grounded and "slightly boring" as Villeneuve put it. Additionally, Young looked towards the book Speedway by photographer Martina Hoogland Ivanow as a reference for the look of the film.

Visual effects
Production designer Patrice Vermette discussed the film in a February 2017 interview with Popular Mechanics, stating that a big influence on the look of the film was the works of artist James Turrell, particularly the design of the meeting room aboard the alien craft. "I wanted the simplicity and the sensorial experience you feel in a room like that. That big screen was always there in the script, and I used it as an element to unite Louise's world. For me, that big screen is more than a screen—that room, which they called in the script 'the interview room,' is a classroom. That big white screen, [you see it] represented in Louise's house with the big window. You also see it in her school, in her classroom."

Rodeo FX completed 60 visual shots for the film, and stated that the biggest challenge for them was the sequence in which Louise and Ian first enter the alien craft.

The asteroid 15 Eunomia is the inspiration for the look of the heptapod ships.

Linguistics
Both the book and the screenwriting required the invention of a form of alien linguistics which recurs in the plot. The film uses a script designed by the artist Martine Bertrand (wife of the production designer Patrice Vermette), based on scriptwriter Heisserer's original concept. Computer scientists Stephen and Christopher Wolfram analyzed it to provide the basis for Banks's work in the film. Their works are summarized in a GitHub repository. Three linguists from McGill University were consulted. The sound files for the alien language were created with consultation from Morgan Sonderegger, a phonetics expert. Lisa Travis was consulted for set design during the construction of the scientist's workplaces. Jessica Coon, a Canada Research Chair in Syntax and Indigenous Languages, was consulted for her linguistics expertise during the review of the script. Heisserer said at the Alamo Drafthouse's Fantastic Fest premiere of Arrival at the end of September 2016 that Shang's wife's last words, translated into English, were "In war, there are no winners, only widows". Villeneuve decided not to include subtitles for the line; Heisserer said he would have preferred it not be kept secret, and was happy to reveal the translation.

Music and soundtrack

Jóhann Jóhannsson began writing the score as the shooting started, drawing on the screenplay and concept art for inspiration. He developed one of the main themes in the first week using vocals and experimental piano loops. The original soundtrack was released by Deutsche Grammophon on November 11, 2016.

Max Richter's pre-existing piece "On the Nature of Daylight" is featured in the film's opening and closing scenes. Due to the prominent use of Richter's music, which had also featured in Martin Scorsese's film Shutter Island, Jóhannsson's score was deemed ineligible for the Academy Award for Best Original Score, the rationale being that voters would be influenced by the use of pre-existing music when judging the merits of the score.

Marketing and release
A teaser trailer was released in August 2016, followed the next week by the first official trailer. Paramount Pictures released a series of promotional posters, with one showing a UFO hovering above a Hong Kong skyline that included Shanghai's Oriental Pearl Tower. The inaccuracy angered Hong Kong social media users. The posters were withdrawn and a statement attributed the inaccuracy to a third-party vendor.

In May 2014, while titled Story of Your Life, Paramount acquired the US and Canadian distribution rights. Shortly after, Sony Pictures Releasing International and Stage 6 Films acquired some international distribution rights, while Entertainment One acquired the UK distribution rights and Roadshow Films acquired Australian distribution rights. Spentzos Films acquired distribution rights for Greece, Reliance Entertainment for India (ultimately it was MVP Entertainment that released it there), Lev Cinemas for Israel, Italia Films for the UAE, and Chantier Films for Turkey. The film had its world premiere at the Venice Film Festival on September 1, 2016. It also screened at the Toronto International Film Festival, the Telluride Film Festival, and the BFI London Film Festival. The film was released on November 11, 2016.

Home media
Arrival was released on Digital HD on January 31, 2017 and on Ultra HD Blu-ray, Blu-ray and DVD on February 14, 2017.

Reception

Box office
Arrival grossed $100.5 million in the United States and Canada, and $102.8 million in other countries, for a worldwide total of $203.4 million, against a production budget of $47 million.

In the United States and Canada, Arrival was released alongside Almost Christmas and Shut In, and was originally expected to gross around $17 million from 2,317 theaters in its opening weekend, with the studio projecting a more conservative debut of $12–15 million. The film made $1.4 million from Thursday night previews at 1,944 theaters and $9.4 million on its first day, pushing projections up to $24 million. It ended up grossing $24.1 million over the weekend, finishing third at the box office. In its second weekend, the film grossed $12.1 million (a drop of 49.6%), and in its third made $11.5 million (dropping just 5.6%). Following its eight Oscar nominations, the film returned to 1,221 theaters on January 27, 2017 (an increase of 1,041 from the week before) and grossed $1.5 million (up 357.4% from its previous week's $321,411).

Critical response

On Rotten Tomatoes, the film has an approval rating of 94% based on 439 reviews, with an average rating of 8.40/10. The website's critical consensus reads, "Arrival delivers a must-see experience for fans of thinking person's sci-fi that anchors its heady themes with genuinely affecting emotion and a terrific performance from Amy Adams." On Metacritic, the film has a score of 81 out of 100, based on 52 reviews, indicating "universal acclaim". Audiences polled by CinemaScore gave the film an average grade of "B" on an A+ to F scale.

Robbie Collin of The Telegraph praised the film, calling it "introspective, philosophical and existentially inclined—yet [it] unfolds in an unwavering tenor of chest-tightening excitement. And there is a mid-film revelation—less a sudden twist than sleek unwinding of everything you think you know—that feels, when it hits you like your seat is tipping back."  Brian Tallerico of RogerEbert.com gave the film three out of four: "It's a movie designed to simultaneously challenge viewers, move them and get them talking. For the most part, it succeeds." For Time, Sam Lansky described it as "sophisticated, grownup sci-fi: a movie about aliens for people who don't like movies about aliens". IGN reviewer Chris Tilly gave it a score of 8.5 out of 10, saying: "Arrival is a language lesson masquerading as a blockbuster, though much more entertaining than that sounds… it's smart, sophisticated sci-fi that asks big questions, and does a pretty good job of answering them". Kenneth Turan of the Los Angeles Times praised Adams's performance, stating "Arrival is really Adams' film, a showcase for her ability to quietly and effectively meld intelligence, empathy, and reserve". Writing for USA Today, Brian Truitt referred to Adams as a "definite Oscar contender", and credited Adams as "spectacular in giving Louise the right emotional balance".

Conversely, Forrest Wickman of Slate had a more mixed opinion of the film, praising the cinematography and musical score, but stating that he thought it was similar to Christopher Nolan's "only intermittently stellar" Interstellar, and criticizing the dialogue as "clunky".

Rex Reed, writing for the New York Observer, gave the film one out of four, calling it Villeneuve's "latest exercise in pretentious poopery" and referring to a lack of action in the storyline.

The Guardian rated it as the third-best film of 2016. Critic Catherine Shoard said that it "amounts to something transcendent; something to reignite your excitement for cinema, for life". Numerous other publications and websites, including io9, Den of Geek, Mir Fantastiki, The Atlantic, Blastr, and Digital Trends named Arrival the best film of 2016.

Response from academics

David Adger, a linguistics professor who teaches at Queen Mary University of London, had a favorable view of the accuracy of the linguistics in Arrival, saying that "the portrayal of trying different hypotheses about the language, coming up with generalizations, and testing them out was spot on."

Similarly, Jessica Coon, a linguistics professor who teaches at McGill University and helped with the film's linguistics, stated that "what the film gets exactly right is both the interactive nature but also that you really have to start small." She noted that the creators had not invented a complete language.

Linguistics professor Betty Birner, who teaches at Northern Illinois University, said that the film's use of the Sapir–Whorf hypothesis went "beyond anything that is plausible".  She also felt the film oversimplified the process of translating the aliens' language, skipping straight from Banks establishing the basic vocabulary of the language, to her being able to understand abstract concepts such as "weapon".

Accolades, awards and nominations

Arrival received numerous nominations and awards. At the 89th Academy Awards, it won the Academy Award for Best Sound Editing, and had received nominations for Best Picture, Best Director, Best Adapted Screenplay, Best Cinematography, Best Film Editing, Best Production Design and Best Sound Mixing. Additionally, at the 74th Golden Globes, Adams had received a nomination for Best Actress in a Motion Picture – Drama, and composer Jóhann Jóhannsson had received a nomination for Best Original Score.

See also
 Alien language in science fiction
 List of films featuring extraterrestrials

Notes

References

Further reading

External links

 Official screenplay

2010s mystery drama films
2010s science fiction drama films
2016 thriller films
American mystery thriller films
American nonlinear narrative films
American science fiction thriller films
American psychological thriller films
American science fantasy films
BAFTA winners (films)
Alien visitations in films
Films about extraterrestrial life
Films about language
Films about precognition
Films based on American short stories
Films based on science fiction short stories
Films directed by Denis Villeneuve
Films scored by Jóhann Jóhannsson
Films set in Montana
Films shot in Montreal
Hugo Award for Best Dramatic Presentation, Long Form winning works
Films that won the Best Sound Editing Academy Award
FilmNation Entertainment films
21 Laps Entertainment films
Paramount Pictures films
IMAX films
Lava Bear Films films
Stage 6 Films films
Films about interpreting and translation
Works about Chinese military personnel
2010s English-language films
2010s American films
Fictional-language films

Arrival (film)


The Sea Mammal Research Unit (SMRU) is a marine science research organisation in Fife, Scotland. It provides the UK's main science capability in the field of marine mammal biology. It is located at the Gatty Marine Laboratory, part of the University of St Andrews. It was established in 1978, when the Natural Environment Research Council merged its Seals Research Division and Whale Research Unit.

SMRU's current strategic science priorities include evaluating the status of marine mammal populations; investigating the importance of marine mammals as components of marine ecosystems; determining the dynamics of marine mammal populations; studying marine mammal social structure and communication; providing the technological basis for observing free-ranging marine mammals and their environment. SMRU also uses the popularity of marine mammals to improve public knowledge about the marine environment.

SMRU's activities address the requirements for information about marine mammals identified in the UK and Scottish Sustainable Development and Biodiversity Strategies and the Strategy for Scotland's Coast and Inshore Waters. It is also relevant to the Joint UK Response to the Review of Marine Nature Conservation, the EU Marine Strategy and the UK Small Cetacean Bycatch Response Strategy.

SMRU is an independent NERC collaborative centre. The funding it receives from NERC is mainly to support the Conservation of Seals Act 1970. SMRU focuses over half of its research effort on cetaceans. In agreement with NERC, SMRU raises the remainder of its funding from other sources. These include the European Union, Defra, Scottish Government and UK Ministry of Defence. It also develops and supplies instrumentation to the science community.

SMRU Consulting Ltd (Europe) was set up in 2006 as the commercial arm of the Sea Mammal Research Unit at the University of St Andrews and provides consultancy services and advice on marine environmental issues. They have offices in Europe, North America and Asia-Pacific.

Notable SMRU Consulting projects includes Marine Mammal Mitigation on the world's first commercial tidal device at Strangford Loch and the development of PAMBuoy, now Decimus - run by St Andrews Instrumentation Ltd.

On 1 June 2016, a dead Minke whale washed ashore on the West Sands beach of St. Andrews, near to the SMRU, and was discovered by a dog walker that evening. During low-tide on 2 June, staff and students from the SMRU, along with the Scottish Marine Animal Strandings Scheme, jointly conducted a necropsy of the whale in view of the public. Noting signature abrasions on the tailstock, and excessive fluid in the lungs, they concluded that the animal had been caught in a fishing trawler's lines, and was drowned by the dragging.

References

External links
 Scottish Oceans Institute (Gatty Marine Laboratory) Homepage
 Sea Mammal Research Unit Homepage
 St Andrews University
 Natural Environment Research Council (NERC)
 SMRU Consulting - commercial Arm of the Sea Mammal Research Unit
 - SeaGen is the name given to the 1.2MW tidal energy convertor(sic) that was installed in Strangford Lough
 - Real-time marine mammal detection and noise level measurement

Biological research institutes in the United Kingdom
Natural Environment Research Council
Oceanographic organizations
University of St Andrews
Science and technology in Scotland
Scientific organisations based in the United Kingdom
Organisations based in Fife
1978 establishments in Scotland
Scientific organizations established in 1978
Research institutes in Scotland
Cetacean research and conservation
Marine mammal rehabilitation and conservation centers

Sea Mammal Research Unit


The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation.  Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known.

When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature.  The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect.

Star

The effective temperature of a star is the temperature of a black body with the same luminosity per surface area () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total (bolometric) luminosity of a star is then , where  is the stellar radius. The definition of the stellar radius is obviously not straightforward. More rigorously the effective temperature corresponds to the temperature at the radius that is defined by a certain value of the Rosseland optical depth (usually 1) within the stellar atmosphere. The effective temperature and the bolometric luminosity are the two fundamental physical parameters needed to place a star on the Hertzsprung–Russell diagram. Both effective temperature and bolometric luminosity depend on the chemical composition of a star.

The effective temperature of the Sun is around .
The nominal value defined by the International Astronomical Union for use as a unit of measure of temperature is .
Stars have a decreasing temperature gradient, going from their central core up to the atmosphere. The "core temperature" of the Sun—the temperature at the centre of the Sun where nuclear reactions take place—is estimated to be 15,000,000 K.

The color index of a star indicates its temperature from the very cool—by stellar standards—red M stars that radiate heavily in the infrared to the very hot blue O stars that radiate largely in the ultraviolet. Various colour-effective temperature relations exist in the literature. There relations also have smaller dependencies on other stellar parameters, such as the stellar metallicity and surface gravity. The effective temperature of a star indicates the amount of heat that the star radiates per unit of surface area. From the hottest surfaces to the coolest is the sequence of stellar classifications known as O, B, A, F, G, K, M.

A red star could be a tiny red dwarf, a star of feeble energy production and a small surface or a bloated giant or even supergiant star such as Antares or Betelgeuse, either of which generates far greater energy but passes it through a surface so large that the star radiates little per unit of surface area. A star near the middle of the spectrum, such as the modest Sun or the giant Capella radiates more energy per unit of surface area than the feeble red dwarf stars or the bloated supergiants, but much less than such a white or blue star as Vega or Rigel.

Planet

Blackbody temperature

To find the effective (blackbody) temperature of a planet, it can be calculated by equating the power received by the planet to the known power emitted by a blackbody of temperature .

Take the case of a planet at a distance  from the star, of luminosity .

Assuming the star radiates isotropically and that the planet is a long way from the star, the power absorbed by the planet is given by treating the planet as a disc of radius , which intercepts some of the power which is spread over the surface of a sphere of radius  (the distance of the planet from the star). The calculation assumes the planet reflects some of the incoming radiation by incorporating a parameter called the albedo (a). An albedo of 1 means that all the radiation is reflected, an albedo of 0 means all of it is absorbed. The expression for absorbed power is then:

The next assumption we can make is that the entire planet is at the same temperature , and that the planet radiates as a blackbody. The Stefan–Boltzmann law gives an expression for the power radiated by the planet:

Equating these two expressions and rearranging gives an expression for the effective temperature:

Where  is the Stefan–Boltzmann constant. Note that the planet's radius has cancelled out of the final expression.

The effective temperature for Jupiter from this calculation is 88 K and 51 Pegasi b (Bellerophon) is 1,258 K.  A better estimate of effective temperature for some planets, such as Jupiter, would need to include the internal heating as a power input.  The actual temperature depends on albedo and atmosphere effects. The actual temperature from spectroscopic analysis for HD 209458 b (Osiris) is 1,130 K, but the effective temperature is 1,359 K. The internal heating within Jupiter raises the effective temperature to about 152 K.

Surface temperature of a planet

The surface temperature of a planet can be estimated by modifying the effective-temperature calculation to account for emissivity and temperature variation.

The area of the planet that absorbs the power from the star is  which is some fraction of the total surface area , where  is the radius of the planet. This area intercepts some of the power which is spread over the surface of a sphere of radius . We also allow the planet to reflect some of the incoming radiation by incorporating a parameter  called the albedo. An albedo of 1 means that all the radiation is reflected, an albedo of 0 means all of it is absorbed. The expression for absorbed power is then:

The next assumption we can make is that although the entire planet is not at the same temperature, it will radiate as if it had a temperature  over an area  which is again some fraction of the total area of the planet. There is also a factor , which is the emissivity and represents atmospheric effects.  ranges from 1 to 0 with 1 meaning the planet is a perfect blackbody and emits all the incident power. The Stefan–Boltzmann law gives an expression for the power radiated by the planet:

Equating these two expressions and rearranging gives an expression for the surface temperature:

Note the ratio of the two areas. Common assumptions for this ratio are  for a rapidly rotating body and  for a slowly rotating body, or a tidally locked body on the sunlit side. This ratio would be 1 for the subsolar point, the point on the planet directly below the sun and gives the maximum temperature of the planet — a factor of  (1.414) greater than the effective temperature of a rapidly rotating planet.

Also note here that this equation does not take into account any effects from internal heating of the planet, which can arise directly from sources such as radioactive decay and also be produced from frictions resulting from tidal forces.

Earth effective temperature

Earth has an albedo of about 0.306 and a solar irradiance () of  at its mean orbital radius of 1.5×108 km.  The planet is a fairly fast rotator so the area ratio can be estimated as . The calculation with ε=1 and remaining physical constants then gives an Earth effective temperature of .

The actual temperature of Earth's surface is an average  as of 2020. The difference between the two values is called the greenhouse effect. The greenhouse effect results from materials in the atmosphere (greenhouse gases and clouds) absorbing thermal radiation and reducing emissions to space, i.e., reducing the planet's emissivity of thermal radiation from its surface into space. Substituting the surface temperature into the equation and solving for ε gives an effective emissivity of about 0.61 for a 288 K Earth. Furthermore, these values calculate an outgoing thermal radiation flux of  (with ε=0.61 as viewed from space) versus a surface thermal radiation flux of  (with ε≈1 at the surface). Both fluxes are near the confidence ranges reported by the IPCC.

See also

References

External links
 Effective temperature scale for solar type stars
 Surface Temperature of Planets
 Planet temperature calculator

Stellar astronomy
Planetary science
Thermodynamic properties
Electromagnetic radiation
Concepts in astronomy

Effective temperature