Wells invents the hostile Martian
Wells's Martians land near Woking, burn Surrey with a heat-ray, and die of bacteria. The invading alien enters the culture and never leaves it.
H. G. Wells serialised The War of the Worlds in Pearson's Magazine in Britain and The Cosmopolitan in America from April to December 1897; Heinemann published the book in January 1898. Cylinders come down on Horsell Common near Woking, unscrew, and disgorge machines that walk. A heat-ray flattens Surrey. The British Army, at the height of the empire, is irrelevant within days. The Martians are then killed by terrestrial bacteria, having no immunity to them — an ending that turns on microbiology rather than heroism, which in 1898 was a genuinely new move.
The science under it was the science of the moment. Mars was understood to be older than Earth, colder, and drying out; that is Schiaparelli's and Lowell's Mars, and Wells simply asked what its inhabitants would do about it. The answer is that they would come here. The politics under it was as deliberate: Wells opens by comparing the invasion to the extermination of the Tasmanians, and the novel is at least as much about the British Empire as about Mars.
A second Martian arrived in 1912, when Edgar Rice Burroughs published Under the Moons of Mars in All-Story Magazine — the Barsoom of dying sea-bottoms, thin air and warring races, later collected as A Princess of Mars. Between them Wells and Burroughs fixed the two settings the culture still uses: Mars as a threat, and Mars as somewhere to go. Carl Sagan and Ray Bradbury both said Burroughs got them started.
Then on 30 October 1938 the Mercury Theatre on the Air put a version of Wells on CBS, with Orson Welles, aged 23, directing and a script by Howard Koch that moved the landings to Grovers Mill, New Jersey and presented the first act as breaking news bulletins. The famous consequence — a nation fleeing into the streets — is largely a newspaper invention. The show aired opposite the most popular programme in America and had a modest audience; later work by Jefferson Pooley, Michael Socolow and A. Brad Schwartz found frightened, confused listeners in real numbers but no mass panic. The press, with reasons of its own to argue that radio was dangerous, ran the hysteria headlines anyway.
That is the era in miniature. A wrong story about Mars outlived the correction, and a wrong story about the story outlived it too. When Mariner 4's pictures came back in 1965, part of what they killed was Wells's Mars.