"The Earth is the cradle of mind, but one cannot live forever in the cradle"
ALSO:"The Earth is the cradle of mankind, but mankind cannot stay in the cradle forever."
"Konstantin Tsiolkovsky (1857 — 1935)
One of the foundators of the modern rocket science (with Robert Goddard and Hermann Oberth), also called "Father of Astronautics". Tsiolkovsky was a russian schoolteacher fascinated by the potential for space flight. His research first suggested that rockets could function outside of the Earth’s atmosphere with a self-contained propulsion system that would not rely on oxygen. Tsiolkovsky introduced many of the basic concepts of space travel that scientists still use today (ie: the necessity of sealed cabins with oxygen for humans to survive in space). He calculated the speed (just under 7 miles per second) and amount of fuel a rocket would need in order to attain scape velocity from Earth.