Abstract: civilization and they will become ever more important as the num ber of people on the earth increases and the poorer nations push toward a higher standard of living. Only when men could multiply the work of their muscles many fold by the use of power machines could they have a chance for a successful economy which assured sufficient food, adequate education, and modern conveniences of living. Our present dependence on mechanical energy is astonishing. In agriculture, by way of example, for every calorie of food produced in the United States another calorie of fuel has been consumed in preparation of that food?with tractor ploughing, mechanical harvesting, food processing, motor transportation, and delivery. Thus, under current practices, when we run out of fuel we will run out of food also. At present the world has an ample supply of fossil fuels (coal, oil, and gas) but they are not distributed evenly and they will not last in definitely. Our engineering is geared to these fossil fuels which were produced by sunlight long ago and preserved for us through geological accidents. We are fortunate to have had these transportable, concen trated sources of energy, but, looking ahead, we are trying through re search and engineering to develop new sources of energy. Atomic energy through fission came as a surprise a quarter of a century ago and its com mercial use is now here. A future but still uncertain source of energy may be the nuclear fusion of the oceans' hydrogen. Scientists and engineers should now give more serious attention to finding practical ways to use the sun's energy directly. There is an ample supply of solar radiation falling on the earth to do all the work that will conceivably be needed, and a new supply will always be available every sunny day?as long as there are people on the earth. But the intensity of solar radiation is low and large areas are required for collecting it; large areas of any material are expensive. Moreover, the solar radiation is in termittent due to regular interruption by night and irregular interruption by clouds, so that costly devices are usually needed for storing the energy obtained when the sun is shining. In the future, atomic energy and solar energy should be comple mentary rather than competitive?atomic energy will be produced in large units requiring high capital investment in temperate latitudes and cloudy areas, and near cities, where there is not enough sunlight to sup ply the concentrated energy needs. Solar energy will be used in the sun * A Sigma Xi-BESA National Lecture, 1964 and 1966. 15
Publication Year: 1984
Publication Date: 1984-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 112
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