Environmental Perspectives

摘要

We live in an electromagnetic environment. We also live in a sometimes-hostile regulatory and legal environment. One of the cornerstones of modern civilization is our ability to generate and transmit energy via electromagnetic fields. Even if all man-made sources of electromagnetic fields were turned off, however, we would still live in an electromagnetic environment. The natural-origin electric field at the surface of the earth measures on the order of about 100 V/m and the earth's magnetic flux density is about 0.5 Gauss. The electric field across the membrane of every cell can be in excess of 10~5 V/m — and is an essential force of life. In fact, when Volta himself stimulated the sciatic nerve of a frog resulting in the contraction of the leg muscle in the early 19th century he was convinced he had discovered the secret of life. He found one of them, certainly.