The twenty-seventh century, seven hundred years from now. If we are only a twelve centuries out of the dark ages, exponentially speaking, why not 2700AD? Some may think this too soon to have reached a level 2 civilization, but others might agree. I’m rooting for mankind. And since its probably my decision in the end, I’m going with the 27th century. Any thoughts on what life might be like at that time?
Von Neumann Probes
In essence, self replicating probes work as follows: A fully-automated probe is launched toward a nearby star via a propulsion system. When it enters that star system decades (or centuries) later, it exhaustively surveys what lies there. It transmits what it learns back to its home planet, which for our purposes, is Planet Earth. It then uses the material resources of the star system present in asteroids, comets, moons, and/or planets to construct replicas of itself, which it sends to other nearby star systems to repeat the process, looking for a new perfect Earth.
They would be in essence miniature flying factories, designed to use advanced robotic systems to mine and process ore, harvest raw materials, fabricate individual components, and assemble all the varied parts into a whole probe. Depending on the complexity of the probe and the sophistication of the robotic systems involved, the process to produce a single daughter probe can vary from a few days to several years.
The original probe may stay in the system or continue on, depending on its mission parameters. If it stays, it may act as a communication relay between its "children" and its home planet, or it may begin processing the system’s resources for anticipated follow-up colonization ships from the home planet, or it may launch resources back to its point of origin for its building race’s material needs.
For our needs, it will actually prepare the new planet for all the inhabitants of Earth.