Even more fun, I learned from Bruce Schneier's blog post [1] that it takes a minimum 4.4E-16 ergs of energy for an ideal computer running at 4.4K to "flip a bit

Even more fun, I learned from Bruce Schneier's blog post [1] that it takes a minimum 4.4E-16 ergs of energy for an ideal computer running at 4.4K to "flip a bit" in an ideal setting. Wolfram says there are roughly 2E76 ergs of mass-energy in the universe. [2] So even if all matter and energy in the universe were put together to power a computer that did nothing but count upwards from zero, there's only enough matter and energy in our universe for the computer to count to about 10^91, or roughly 2^304 [3]. That's not even counting trying to use each resulting set of bits for anything. So I don't think we'd be able to design too many useful computers by flipping bits until a useful algorithm comes out (at least not in this universe.) [1] https://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html https://www.schneier.com/blog/archives/2009/09/the_doghouse_... [2] http://www.wolframalpha.com/input/?i=mass-energy+in+the+known+universe+in+ergs http://www.wolframalpha.com/input/?i=mass-energy+in+the+know... [3] http://www.wolframalpha.com/input/?i=log2(mass-energy+of+the+known+universe+%2F+(4.4E-16+ergs) http://www.wolframalpha.com/input/?i=log2(mass-energy+of+the...)