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Originally Posted by anotherT34C  Just to correct a few folks who dismiss this out of hand, claiming thermodynamics, I'd point out that this isn't necessarily so. In this case, it is, but not for the reasons often given. A natural process can create a fuel that stores more energy than what is required to liberate it (case: oil, coal, uranium), provided that the process of creation of that fuel more than pays the total energy budget. In all three examples, the energy source is nuclear fusion in a star.
As for the source of the star... that's a bit more speculative (though there are some very sophisticated guesses). |
I'm not quite sure what you mean. The first two items you list took much more energy to form than we get out of them by burning. Just because humans didn't put in the energy doesn't mean that the chemical energy stored in the bonds and released when they are burned didn't exist. The first two items are reduced forms of carbon. Carbon is reduced from naturally occurring carbon dioxide by living things using outside energy sources, either sunlight, or as we have recently found out residual/nuclear heat from the earth. (much of the heat that keeps our planet's interior hot comes from the decay of radioactive isotopes). It seems to me that you are saying these things came into existance without an energy source.
The later item, uranium, energy comes from the splitting of atoms. Since only Hydrogen and helium were produced by the big bang, all heavier elements were created by nuclear fusion in stars up to iron. Elements heavier than iron were only created in the temperatures and pressures available in supernova explosions and take energy to make rather than giving off energy in fusion like lighter elements. The energy stored in the nucleus of a uranium atom available for our extraction was put there by a supernova.
Thermodynamics still works as far as I can tell with these examples.