Earlier quoted context omitted.
Programming machines to make the trip and then seeding with human life seems to be the best answer to distance.
That would be so interesting - could be many a sci-fi stories created on that premise. Some mechanical robot/starship storing frozen embryos for 100 years to be released on a far-away exoplanet, the starship taking care of them while they grow up and learn how to live on this new world - the beginnings of a new civilization - a technological adam and eve of sorts.
You've got people living their every day lives, when a probe from space lands and starts producing aliens. At first it's treated as a strange curiosity, but with time the aliens begin to make inroads conquering the planet. Ending twist: the aliens are humans, and the "people" were aliens!