In 1964, Russian Astrophysicist Nikolai Kardashev postulated that advanced civilizations can be categorized by the total amount of energy and resulting technology available to them. He called it the Kardashev Scale. He initially came up with 3 civilization types, however, other astronomers have recently extended the scale from type 0 all the way to type 7 as new theories in modern physics and advanced civilizations have emerged.