"The Earth is the cradle of humanity, but one cannot live in a cradle forever."
Humanity traveling to the stars is an ancient dream, and a late nineteenth and early twentieth century project, proposed quickly after the first developments in rocketry. The idea spread through world culture, mainly by way of science fiction. Countless stories described people visiting planets orbiting other stars, and by a process of cultural diffusion, space travel became one part of a plausible and widely-held consensus future for humanity, a future we seemed to moving into with accelerating speed as the twentieth century progressed.
With the enormous successes of Star Trek and Star Wars, the idea was firmly planted in the popular imagination: if we survived as a species, we would be moving out into the galaxy. This awesome diaspora would mark our maturity or success as a species, and would enable us to outlive the Earth itself, should it suffer a natural disaster or be destroyed by some human folly. The thought of long-term galactic survival for humanity was comforting to some, and in any case it seemed inevitable, humanity's fate or destiny. When we landed people on the moon in 1969, and robots on Mars in 1976, it seemed we were already on the way. (more…)