How to build a planet

Without giving spoilers, this idea comes from the movie Titan A.E. How would one create an Earth-like planet in a reasonable time frame (100-250 years) that has both the gravity of Earth and a magnetic field?

For the purposes of this question, assume that the people have sufficiently advanced interstellar space travel to make this viable and they want to create an exact replica of Earth as it was before the Andromeda-Milky Way collision after our Sun expands and the Solar System is thrown out of the Galaxy.

EDIT:

It took the earth 200 Million years to cool after its initial formation 4.5 billion years ago. To clarify, I am more interested in how one would drastically speed up the natural formation of an Earth-sized planet and its cooling afterward to the 250 years time frame listed above. After that it should be trivial for a civilization of this technology level to add a breathable atmosphere and some ocean water.

posted about 9 years ago

JDSweetBeat‭

11 reputation 49 1 1 0