Welteislehre (WEL; "World Ice Theory" or "World Ice Doctrine"), also known as Glazial-Kosmogonie (Glacial Cosmogony), is a discredited cosmological concept proposed by Hanns Hörbiger, an Austrian engineer and inventor.
Hörbiger did not arrive at his ideas through research, but said that he had received it in a "vision" in 1894. According to his ideas, ice was the basic substance of all cosmic processes, and ice moons, ice planets, and the "global ether" (also made of ice) had determined the entire development of the universe.
By his own account, Hörbiger was observing the Moon when he was struck by the notion that the brightness and roughness of its surface was due to ice. Shortly after, he experienced a dream in which he was floating in space watching the swinging of a pendulum which grew longer and longer until it broke. "I knew that Newton had been wrong and that the sun's gravitational pull ceases to exist at three times the distance of Neptune," he concluded. He worked out his concepts in collaboration with amateur astronomer and schoolteacher Philipp Fauth whom he met in 1898, and published it as Glazial-Kosmogonie in 1912. Fauth had previously produced a large (if somewhat inaccurate) lunar map and had a considerable following, which lent Hörbiger's ideas some respectability.
It did not receive a great deal of attention at the time, but following World War I Hörbiger decided to change his strategy by promoting the new "cosmic truth" not only to people at universities and academies, but also to the general public. Hörbiger thought that if "the masses" accepted his ideas then they might put enough pressure on the academic establishment to force his ideas into the mainstream. No effort was spared in popularising the ideas: "cosmotechnical" societies were founded, which offered public lectures that attracted large audiences, there were cosmic ice movies and radio programs, and even cosmic ice journals and novels.
The followers of WEL exerted a great deal of public pressure on behalf of the ideas. The movement published posters, pamphlets, and books, and even a newspaper, The Key to World Events. A company owned by an adherent would only hire people who declared themselves convinced of the WEL's truth. Some followers even attended astronomical meetings to heckle, shouting, "Out with astronomical orthodoxy! Give us Hörbiger!" During this period, the name was changed from the Graeco-Latin Glazial-Kosmogonie to the more Germanic Welteislehre [WEL] ("World ice theory").