Many novels focusing on life on other planets written close to 1900 echo scientific ideas of the time, including Pierre-Simon Laplace's nebular hypothesis, Charles Darwin's theory of natural selection, and Gustav Kirchhoff's theory of Spectroscopy. These scientific ideas combined to present the possibility that planets are alike in composition and conditions for the development of species, which would likely lead to the emergence of life at a suitable geological age in a planet's development.
By the time Wells wrote The War of the Worlds there had been three centuries of observation of Mars through telescopes. Galileo in 1610 observed the planet's phases, and in 1666 Giovanni Cassini identified the polar ice caps. In 1878 Italian astronomer Giovanni Schiaparelli observed geological features which he called canali (Italian for "channels"). This was mistranslated into English as "canals" which, being artificial watercourses, fuelled the belief in intelligent extraterrestrial life on the planet. This further influenced American astronomer Percival Lowell.
In 1895 Lowell published a book entitled Mars which speculated about an arid, dying landscape, whose inhabitants built canals to bring water from the polar caps to irrigate the remaining arable land. This formed the most advanced scientific ideas about the conditions on the red planet available to Wells at the time The War of the Worlds was written; but the concept was later proved erroneous by more accurate observation of the planet, and later landings by Russian and American probes such as the two Viking missions, that found a lifeless world too cold for water to exist in its liquid state.
The Martians travel to the Earth in cylinders, apparently fired from a huge space gun on the surface of Mars. This was a common representation of space travel in the nineteenth century, and had also been used by Jules Verne in From the Earth to the Moon. Modern scientific understanding renders this idea impractical, as it would be difficult to control the trajectory of the gun precisely, and the force of the explosion necessary to propel the cylinder from the Martian surface to the Earth would likely kill the occupants.
However, the 16-year-old Robert H. Goddard was inspired by the story and spent much of his life inventing rockets. The research into rockets begun by Goddard eventually culminated in the Apollo program's manned landing on the moon, and the landing of robotic probes on Mars.
The Martian invasion's principal weapons are the 'Heat-Ray' and the poisonous 'Black Smoke'. Their strategy includes the destruction of infrastructure such as armament stores, railways, and telegraph lines; it appears to be intended to cause maximum casualties, leaving humans without any will to resist. These tactics became more common as the twentieth century progressed, particularly during the 1930s with the development of mobile weapons and technology capable of 'surgical strikes' on key military and civilian targets.
Wells's vision of a war bringing total destruction without moral limitations in The War of the Worlds were not taken seriously by readers at the time of publication. He later expanded these ideas in the novels When the Sleeper Wakes (1899), The War in the Air (1908), and The World Set Free (1914). This kind of 'total war' did not become fully realised until the Second World War.
As noted by Howard Black: "(...) In concrete details the Martian Fighting Machines as depicted by Wells have nothing in common with tanks or dive bombers, but the tactical and strategic use made of them is strikingly reminiscent of Blitzkrieg as it would be developed by the German armed forces four decades later. The description of the Martians advancing inexorably, at lightning speed, towards London; the British Army completely unable to put up an effective resistance; the British government disintegrating and evacuating the capital; the mass of terrified refugees clogging the roads, all were to be precisely enacted in real life at 1940 France.(...) Ironically this 1898 prediction came far closer to the actual land fighting of World War II than Wells did much later, much closer to the actual war, in the 1934 "The Shape of Things to Come".
Weapons and armour
Wells's description of chemical weapons – the Black Smoke used by the Martian fighting machines to kill human beings in great numbers – was a daily reality less than 17 years later . The comparison between lasers and the Heat-Ray was made as early as the later half of the 1950s when lasers were still in development. Prototypes of mobile laser weapons have been developed and are being researched and tested as a possible future weapon in space.
Military theorists of the era, including those of the Royal Navy prior to the First World War, had speculated about building a "fighting-machine" or a "land dreadnought". Wells later further explored the ideas of an armoured fighting vehicle in his short story "The Land Ironclads". There is a high level of science fiction abstraction in Wells's description of Martian automotive technology; he stresses how Martian machinery is devoid of wheels, using the "muscle-like" contractions of metal discs along an axis to produce movement. Electroactive polymers currently being developed for use in sensors and robotic actuators are a close match for Wells' description.
Wells's dramatisation of an ecological threat posed by a rapidly growing alien organism, the Red Weed, which spreads over the English landscape, also has parallels in more modern times. Non-native species such as rabbits, foxes, and prickly pear have been introduced into the Australian landscape, with a devastating impact. Another example is the spread of kudzu in the United States. In Ireland and the United Kingdom, Japanese knotweed has become an invasive species; it was introduced in the nineteenth century. These species were not introduced with the intention of causing deliberate harm.