Sci Fi Setting Idea

For as long as I can remember, I've always loved sci fi. Books, movies, video games, and RPGs. While my desire to play or run in a fantasy, superhero, or other RPG game has always waxed and waned over the months, I'm always in the mood to run or play some sci fi. There's just something about exploring new worlds, encountering new aliens, and dealing with new technologies and cultures that has always spurred my imagination.

I'm currently running an M-Space colonial game, where the players are on an ark colonizing a hostile new world to ensure the survival of humanity. It's been a fun and interesting ride, and I've been blessed by some of the best players a GM could ask for. Still, I always like to brainstorm new ideas for future campaigns, especially with the Microscope game I wish to do, and this is one that I've thought about a bit. Here is one.

Twenty Parsecs

Humanity has, through the use of slow generation ship, colonized many of the planets outside of the Local Interstellar Cloud. Through long gulfs of space and time, they have lost contact with Earth, their homeworld simply becoming the place of legends and folklore. That is, until recently, when a space exploration vessel has crashed on the rim world Morning. The locals have discovered a real, bona-fide Earthling in their midst. What happens to Morning and the other colonies when this discovery is made? And is this the only Earthling that made it, or simply the vanguard of a larger force?

The name comes from Asimov, who calculated that at 20 parsecs, you can no long see the Sun in the night sky. The idea behind this is a political and locale adventure where the world as the players know it is being turned upside down. Earth, the fabled cradle of humanity, is real, and this is something that can shake the very foundation of the Union of Free Planets. Some may accept them with a cautious curiosity, while others may see the explorer(s) as a threat to their identity and independence. Whether or not the Earthlings come in peace, I haven't decided. I like the idea of keeping them mysterious and different, as it will have been several centuries since humans left Earth. I prefer a bit more of an optimistic theme for this campaign, but with the lingering fear of an unknown friend or enemy. I haven't decided on whether there are aliens here or not, but if there are, I prefer them to be crazy lifeforms, not humans with different ears and foreheads. I'd probably stick with M-Space/Mythras combined, with some elements of Traveller/Cepheus Engine thrown in there. Though I have been tempted to go back to Traveller for nostalgia sake.

There are other ideas I have for settings that would be fun, but I'll detail them another time.