Pretty O'Neill cylinders, but... Forum: Spacesettlers
Thread: Pretty O'Neill cylinders, but...
# 5993 bylongsteven@... on Nov. 17, 2004, 10:08 p.m.
Member since 2021-10-03
>
> Geothermal energy would be sustainable and non-polluting (or so I
> hope), so I guess that we have not to worry about Earth becoming
> uninhabitable if we ever get access to such depths.
>