Mars and Martians
The novel originated several 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 civilisation capable of advanced feats of science and engineering, and also being a source of invasion forces, keen to conquer the Earth. The first two tropes were prominent in Edgar Rice Burroughs "Barsoom" series beginning with A Princess of Mars in 1912.
Influential scientist Freeman Dyson, a key figure in the search for extraterrestrial life, also acknowledges his debt to reading H.G. Wells' fictions as a child.
The publication and reception of The War of the Worlds also established the vernacular term of 'martian' as a description for something offworldly or unknown.
Aliens and alien invasion
Wells is credited with establishing several extraterrestrial themes which were later greatly expanded by science fiction writers in the 20th Century, including first contact and war between planets and their differing species. There were, however, stories of aliens and alien invasion prior to publication of The War of the Worlds.
In 1727 Jonathan Swift published Gulliver's Travels. The tale included a race of beings similar but not identical to humanity, who are obsessed with mathematics and are superior to humans. They populate a floating island fortress called Laputa, 4½ miles in diameter, which uses its shadow to prevent sun and rain from reaching earthly nations over which it travels, ensuring they will pay tribute to the Laputians. Voltaire's Micromégas (1752) includes two aliens, from Saturn and Sirius, who are of immense size and visit the Earth out of curiosity. At first they think the planet is uninhabited, due to the difference in scale between them and the peoples of Earth. When they discover the haughty Earth-centric views of Earth philosophers, they are greatly amused by how important Earth beings think they are compared to greater beings in the universe such as themselves.
In 1892 Robert Potter, an Australian clergyman, published The Germ Growers in London. It describes a covert invasion by aliens who take on the appearance of human beings and attempt to develop a virulent disease to assist in their plans for global conquest. It was not widely read, and consequently Wells's vastly more successful novel is generally credited as the seminal alien invasion story.
The first science fiction to be set on Mars may be Across the Zodiac: The Story of a Wrecked Record (1880) by Percy Greg. It was a long-winded book concerned with a civil war on Mars. Another Mars novel, this time dealing with benevolent Martians coming to Earth to give humankind the benefit of their advanced knowledge, was published in 1897 by Kurd Lasswitz — Two Planets (Auf Zwei Planeten). It was not translated until 1971, and thus may not have influenced Wells, 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 civilisation on Mars which, while parallel to that of the Earth has evolved somehow independently.
Early examples of influence on science fiction
Wells had already proposed another outcome for the alien invasion story in The War of the Worlds. When the Narrator meets the artilleryman the second time, the artilleryman imagines a future where humanity, hiding underground in sewers and tunnels, conducts a guerrilla war, fighting against the Martians for generations to come, and eventually, after learning how to duplicate Martian weapon technology, destroys the invaders and takes back the Earth.
Six weeks after publication of the novel, the Boston Post newspaper published another alien invasion story, an unauthorised sequel to The War of the Worlds, which turned the tables on the invaders. Edison's Conquest of Mars was written by Garrett P. Serviss, a now little remembered writer, who described the famous inventor Thomas Edison leading a counterattack against the invaders on their home soil. Though this is actually a sequel to 'Fighters from Mars', a revised and unauthorised reprint of War of the Worlds, they both were first printed in the Boston Post in 1898. Lazar Lagin published "Major Well Andyou" in USSR in 1962, an alternative view of events in "War of the Worlds" from the viewpoint of a traitor.
The War of the Worlds was reprinted in the United States in 1927, before the Golden Age of science fiction, by Hugo Gernsback in Amazing Stories. John W. Campbell, another key science fiction editor of the era, and periodic short story writer, published several alien invasion stories in the 1930s. Many well known science fiction writers were to follow, including Isaac Asimov, Arthur C. Clarke, Clifford Simak and Robert A. Heinlein with The Puppet Masters and John Wyndham with The Kraken Wakes.
The theme of alien invasion has remained popular to the present day and are frequently used in the plots of all forms of popular entertainment including movies, television, novels, comics and video games. Alan Moore's graphic novel, The League of Extraordinary Gentlemen, Volume II, retells the events in The War of the Worlds. In the end of the first issue of Marvel Zombies 5, it is revealed that the main characters will visit a world called "Martian Protectorate" where the events of War of the Worlds are occurring.
The Tripods trilogy of books features a central theme of invasion by alien-controlled tripods.
Other narratives, in addition to utilising the alien invasion trope, also involve the appearance of tripod alien fighting machines. The computer game Half-Life 2 makes an apparent homage to The War of the Worlds in the appearance of tripod fighting machines known as Striders, used by the alien invaders. In the video game Unreal Tournament III, one of the vehicles used by the antagonist is a large "Darkwalker" tripod that functions similarly to those in War of the Worlds.