In 1955, he introduced interstellar travel in вЂњThe Man from NowhereвЂќ trilogy. Frank HampsonвЂ™s British comic Dan Dare offered one of the earliest uses of faster-than-light travel. Writers extrapolated supersonic speeds into the idea of spacecraft traveling at multiples of the speed of light. In 1947, Chuck Yeager broke the speed of sound aboard the Bell X-1 Glamorous Glennis. Within a couple of decades, the fictional idea of faster-than-light travel made intuitive sense to a public familiar with recent supersonic flights. SmithвЂ™s cover story appeared in the same issue of Amazing Stories in 1928 that included Philip Francis NowlanвЂ™s first short story about Anthony (later вЂњBuckвЂќ) Rogers. вЂњDocвЂќ Smith imagined spaceships traveling faster than the speed of light in his вЂњSkylark of SpaceвЂќ stories. But relativistic theory shows that mass increases with acceleration until mass becomes infinite at light speed. In classical physics, speed has no limits.

Scientific understanding of light speed as an absolute natural limit derives from Albert EinsteinвЂ™s publications on special relativity in 1905, confirmed by his work on general relativity in 1916.

Some authors suggested faster-than-light drives, hyper drives, jump drives, worm holes, and black holes. Although some of these ideas predated the space age, after the 1950s, fictional depictions of space travel needed to suggest conceivable ways to cross interstellar distances to seem plausible. The idea that characters can fly from planet to planet, or star to star, defying current science and technology, is central to science fiction.

Superluminal spacelike