Sagan also suggests that, for completeness, an alphabetical scale should be added to indicate the level of social development, expressed in the amount of information available to the civilization. Thus, a Class A civilization would be based on 106 bits of information (less than any recorded human culture), a Class B on 107, a Class C on 108, and so on. Humanity in 1973 would belong to the "0.7 H" class. According to Sagan, the first civilization with which humanity would come into contact could be between "1.5 J" and "1.8 K"; a galactic supercivilization would be at the "3 Q" stage, while a federation of galaxies could be at the "4 Z" stage. The information and energy axes are not strictly interdependent, so even a level Z civilization would not have to be Kardashev Type III. Sagan believed that no civilization had yet reached level Z, speculating that so much unique information would exceed that of all the intelligent species in a galactic supercluster, and observing that the universe is not old enough to exchange information effectively over large distances.
Sagan also suggests that, for completeness, an alphabetical scale should be added to indicate the level of social development, expressed in the amount of information available to the civilization. Thus, a Class A civilization would be b,ased on 106 bits of information (less than any recorded human culture), a Class B on 107, a Class C on 108, and so on. Humanity in 1973 would belong to the "0.7 H" class. According to Sagan, the first civilization with which humanity would come into contact could be between "1.5 J" and "1.8 K"; a galactic supercivilization would be at the "3 Q" stage, while a federation of galaxies could be at the "4 Z" stage. The information and energy axes are not strictly interdependent, so even a level Z civilization would not have to be Kardashev Type III. Sagan believed that no civilization had yet reached level Z speculating that so much unique information would exceed that of all the intelligent species in a galactic supercluster, and observing that the universe is not old enough to exchange information effectively over large distances.