A handful of buildings in California are beginning to try a new kind of indoor lighting: sunlight without windows! It's called Hybrid Solar Lighting -- half solar and half electric. During the day, sunlight pours out of the light fixture; at night, a conventional light bulb takes over. On the roof is a large dish that points at the sun and concentrates the sun into the end of the fiber bundle. The sunlight bounces once off the big mirrored dish, then off of a smaller secondary mirror, which focuses everything down into the fiber.
