On April 25, 1954, researchers from Bell Laboratories astonished reporters by hooking a hand-size silicon panel to a toy Ferris wheel, aiming a light at the contraption and making the wheel turn. According to the Department of Energy, less than 1 percent of all the electricity generated in the United States last year came from solar power, compared with 4 percent from wind, 19 percent from nuclear and 39 percent from coal. "A generation from now, this solar heater can either be a curiosity, a museum piece, an example of a road not taken, or it can be just a small part of one of the greatest and most exciting adventures ever undertaken by the American people," he says. -- Dec.