The Photophone: When Voices Rode on Sunlight
On a June day in 1880, Alexander Graham Bell stood on a rooftop and sent speech down a beam of light. His photophone turned sound into vibrating mirrors, which modulated sunlight and splashed it onto a distant detector. The detector turned light back into electricity; a telephone receiver turned it into a voice again. In that instant, Bell glimpsed a world we now take for granted: optical communication. 🌞🔊