[m463]

> They'll have unlimited energy based on

...probably mining the center of the earth after finding it is methane or similar like thomas gold theorized, something like jupiter.

[Qwertious]

The centre of the earth is iron, it's how compasses work.

[pfdietz]

Note that this is not because the iron there is ferromagnetic (iron loses its ferromagnetism at its Curie temperature, which is far below the temperature of the Earth's core) but because the iron there is liquid, and convection in the core, interacting with magnetic fields, induces electrical currents that generate the field, the "geodynamo". This process is highly nonlinear and not well understood.