Yup, they've got sick twisted CPU's!The fususion thing would be a solution, but they'd still run out of water, eh sometime...if they didn't get out to space...
To get energy from a chemical reaction the reaction has to be spontanious, or a decrease in Delta G. Chemicals, only react spontaniously when they have energy output as the result. This again means releasing they're internal energy.
This means that you can't make the reaction go backwards unless you put the same amount of energy or more into it. And eventually you would run out of reaktive chemicals.
The same principle for the planet core. It won't be hot forever, if the sun doesn't shine....
[This message has been edited by Kolben (edited May 30, 2000).]