In this interview from NOVA/FRONTLINE Special Report: What's Up with the Weather? physics professor Martin Hoffert advocates the need for developing alternative energy sources beyond the fossil fuels we currently rely on for electricity and powering our vehicles. Hoffert says we need to use our imagination to come up with viable solutions soon—for example, harnessing renewable solar power in space—because not only are current energy-producing technologies polluting and potentially dangerous, but the fossil fuels used to generate power are in finite supply.