(Tell me if there is already one of these threads)
Here you can speculate how the kerbolar planets came to be how they are and where they are. Any alien intervention/ presence during the formation can be considered...
To start off, maybe Eeloo used to be one of Jool's moons, but got ejected out by another Jool moon such as Tylo or Laythe...
Questions for you:
(Easter eggs in spoiler)
Was/ is there life on Laythe? How did it get there? Why did it die out? Where does life on Kerbin come from?