The total power utilized by humans worldwide is approximately 15 TW (terawatts). Sunlight striking Earth provides 1.336 kW (kilowatts) per square meter. The surface area of Earth is around 197,000,000 square miles. Explain how much of the Earth's surface would we want to cover with solar energy collectors to power the planet for utilize by all humans? Presume that the energy collectors can only convert 10% of the available sunlight into useful power.