While the photovoltaic effect was discovered in 1839, the first practical silicon solar cell was invented at Bell Labs in 1954 by Daryl Chapin, Calvin Fuller, and Gerald Pearson. They used silicon to convert sunlight directly into electricity with about 6% efficiency. At the time, it was too expensive for home use, but it found its first major application in the space race, powering satellites like Vanguard 1. The invention of the solar cell offered a way to generate power without moving parts or fuel, using the most abundant energy source in the solar system. As efficiency has increased and costs have plummeted, solar power has become a leading technology in the global transition to renewable energy, providing a pathway to reduce dependence on fossil fuels.