That's a far more difficult prediction: what technology will be developed in the next several hundred years. What sticks out as some problems with building a p

That's a far more difficult prediction: what technology will be developed in the next several hundred years. What sticks out as some problems with building a planet are where do you get all of the material, and how would you manage its rotational and revolutional speeds as it grew larger? Propelling a space ship seems fairly simple compared with propelling a planet. Douglas Adams had some things to say about designing planets.