A Second Earth in Our Solar System (?)
Our old view, that the Solar System had nine planets will be supplanted by a view that there are hundreds if not thousands of planets in our Solar System. It could be that there are objects of Earth-mass in the Oort cloud a band of debris surrounding our planetary system but they would be frozen at these distances. They would look like a frozen Earth.
So all we need to do is haul one of those babies into our orbit, defrost it, and start populating. Earth 2, here I come!