SpaceX CEO Elon Musk wants to have a city of a million people on Mars by 2050. That may sound astronomically ambitious considering humans have never set foot on the Martian surface. But is it feasible? How long would it take for humans to colonize another planet? And could it ever be possible for people to colonize worlds outside the solar system?
The answers to these questions depend heavily on which planet you're talking about. For Mars, decades isn't necessarily an unrealistic time frame. Serkan Saydam, deputy director of the Australian Centre for Space Engineering Research and a professor at the University of New South Wales in Sydney, said human colonization of Mars is possible within decades.
