What do you think will happen when the fossil fuels are all burned up? I think nuclear energy will be more utilized (sp?). as it is we have breeder reactors which synthesize potent radioactive isotopes as a by product (but breeder reactors were banned because it was thought bad guys would be able to get their hands on nuclear reactive materials too easily). we also have utilized fusion reactors (forcing hydrogen atoms together and using magnets to keep the heat away from the container, there's a fusion reactor in topomak or someplace like that) but we don't gain energy profit from that. anyway if we can successfully utilized nuclear energy from its fully potential, do you think humans will be able to survive without the sun? (assuming of course we are able to use at least some of the energy to blast away to other planets and find more reactable materials to continue getting energy). I think that humans will be able to survive without the sun if we don't get killed when it eats up the earth.