and a life span that makes it reasonable to undertake the journey from your home-world to the Earth. You can even relax this requirement if you're willing to c

and a life span that makes it reasonable to undertake the journey from your home-world to the Earth. You can even relax this requirement if you're willing to consider generation ships: https://en.wikipedia.org/wiki/Generation_ship https://en.wikipedia.org/wiki/Generation_ship