On Mon, Jun 09, 2003 at 10:19:21AM -0700, Chad Cooper wrote: > An ounce of flesh has more energy than an ounce of solar material, I > think, by a magnitude.
This is nonsense. > A body needs few things to create energy - Water, Oxygen, Carbon, and > Hydrogen - most of which can be extracted from water and the ground. A body does not "create" energy. It can convert energy to another form, however. Chemical to mechanical, for example. > Flesh is quite efficient at generating heat - This is misleading. Heat is easy to generate, just burn something. In fact, combustion is one common way to measure the chemical energy content of a substance. There are lots of good ways to convert chemical energy into heat. > in fact, without catalysts used during protein synthesis, the > operating temperature of the chemical reactions could range in the 300 > degree F range(IIRC). I don't know about your fact here, but it is irrelevant. Do you think 300F is hotter than a burning piece of wood? (Hint: there is a famous SF story that gives you the approximate temperature) > Biological heat engines could be very efficient at converting these > elements into energy, This is nonsense. The best a heat engine can do is an efficiency of 1 - T1/T2. So you want T2 to be very large and T1 very low, which is not the case with an animal. But it is nonsense because a heat engine is NOT a good model for an animal converting chemical energy to mechanical energy. Certainly the body doesn't convert the chemicals to heat and use the heat to power muscle contraction. The muscles are powered directly from chemical reactions -- waste heat is just an undesired byproduct. The body is a chemical engine, not a heat engine. > and would probably be difficult to duplicate. No more difficult than interfacing a computer seamlessly with the human brain. But why would you want to duplicate it? You can do much better. > The reason humans were selected, was because it was found that only > humans had the adaptability to survive for a lifetime as a heat > engine. This is nonsense. > A human body generates 100 Watts of energy at rest. No. Watts are power, not energy. And this is just a rough approximation. Consuming 2000 food calories per 24 hours averages out to about 100W of food power consumption. Some of that will be converted to heat, and some to mechanical work. For example, pushing a turnstile that is resisting with 100 Newtons of force (equivalent to about 22 pounds) at a velocity of 1 meter per second requires 100W. But you can't do that indefinitely. > The United States today uses 3.5 Gigawatts. No. The average ELECTRICAL power consumption over a year in the US is close to 350 GW, not 3.5. If you include all power (not just electrical), the number is about 2800 GW. -- "Erik Reuter" <[EMAIL PROTECTED]> http://www.erikreuter.net/ _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
