Dyson Sphere identifies one of a class of megastructures and is originally credited to the physicist Freeman Dyson. Such a "sphere" would be a system of orbiting space-based solar power|solar-power satellites meant to completely encompass a star and capture most or all of its energy output. Dyson speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization, and proposed that searching for evidence of the existence of such structures might lead to the detection of advanced intelligent extraterrestrial life. Different types of Dyson spheres correlate with information on the Kardashev scale.