In what may be Stephen Hawking’s last major television project, Smithsonian Channel explores his controversial position that the survival of the species depends on inhabiting another planet. Planet Earth has been home to humankind for more than 200,000 years, but with a population of 7.3 billion and counting and limited resources, some scientists believe it might not support human life forever. Stephen Hawking, one of the world’s most prominent scientists, believed that humans must have an interstellar escape plan in place within the next 100 years.