My mother was telling me about some guy on TV that has a business dedicated to starting a new colony on other planets. Apparently he is serious, and making a ton of money from people who want to join. For argument’s sake, let’s suppose that they find a way to live without air. What would happen to the human body if it was subjected to the long-term changes in environment that would come from moving to a planet with different gravitational pull and different air pressure, etc.?