A scheme for classifying advanced technological civilizations proposed by Nikolai Kardashev1 in 1964. He identified three high-level types and defined a logarithmic scale in terms of the power they could muster for the purpose of interstellar communications.

1. Able to harness all of the power available on a single planet. (Estimated 10^16 watts)
2. Able to harness all of the power available from a single star. (Estimated 10^26 watts)
3. Able to harness all of the power available from a single galaxy. (Estimated 10^36 watts)