Energy for a Future Star-Spanning White Civilization

The problems which cause mediocre minds to declare “it’s all hopeless” cause extraordinary minds to find unseen pathways.

by David Sims

A BROWN DWARF star having a mass of 0.05 solar masses contains about 5.9747e+55 hydrogen atoms, making possible a maximum of 1.4937e+55 nuclear reactions by the proton-proton chain, for a maximum total of 6.294e+43 Joules of energy.

If this mass is used in nuclear reactors, and the efficiency is 50% in getting energy from the atoms to the consumers, then the brown dwarf would meet the global energy needs of Earth (at the 2013 level) for 5e22 years.

If that same amount of energy were equally divided up among one billion people, and each person were allocated 500 kilowatt-hours of energy use per day, then the brown dwarf would last, once again, for 5e22 years.

Stars are pretty, but stars are wasteful. Star formation will end, due to a depletion of hydrogen in the Universe, in about one hundred trillion (1e14) years. The stars will have nearly all gone out by 10 trillion years later. It would have been much better, from an engineering standpoint, to bank most of the hydrogen into brown dwarfs and wait for someone to come along to use it, since that way the hydrogen would last for at least a hundred million times longer.

Of course, without so many stars, life might never have evolved. The most wasteful hot blue stars of spectral types O and B were needed, for a while, to produce heavy elements and scatter them as they died in supernovae. The stars of types G, K, and M, forming after the metals became available, were needed to produce intelligent living creatures.

But here we are. Once we figure out how to fuse hydrogen into helium to extract nuclear energy with some efficiency, the need for stars — any stars at all — will be past. They are pretty, but surely the universe could henceforth do with fewer of such expensive decorations.

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