We are at the moment looking at space as something to be entered by the tremendous thrust of a rocket because that is the attitude of attacking the unknown. And that causes us not to realize that we are already on the most magnificently equipped spaceship, which could hardly be improved upon. It has got a source of temperature and energy just at the right distance from it. It's beautifully equipped with oxygen, with food supplies, with all kinds of delightful things to do while on the journey.... and it's traveling through space at a colossal speed... and it's called the planet Earth.