The Kardashev Scale is a means of ranking a civilization (or similar entity or group) by measuring its power generation and usage capacity. It is often misunderstood by assuming that it measures size; however, a civilization that spans an entire galaxy might be of a lower type than expected if it does not actually use the entire galaxy's energy.
The three basic types are as follows:
- Type 1.0 Civilization: Able to use the entire solar energy available to an Earth-sized planet. (1016 watts by Carl Sagan's definition of the scale.)
- Type 2.0 Civilization: Able to use the entire energy output of a star. (1026 watts)
- Type 3.0 Civilization: Able to use the entire energy output of a galaxy. (1036 watts)
The decimals indicate that by more precisely measuring power usage, one can arrive at a value in between the main types; a civilization using 1021 watts could be considered Type 1.5.
Various extensions to the scale have been proposed; two are particularly relevant here. One says that simply multiplying each new type's power by 1010 brings it to the next type, so a Type 4.0 Civilization would use 1046 watts, a Type 5.0 Civilization would use 1056, and so on. The values of higher -verses depends heavily on the accepted size of these -verses, which varies based on the cosmology being used.
The other is to simply keep going up from the "planet, star, galaxy" progression, so a Type 4.0 would use the power of a universe, a Type 5.0 would use the power of a multiverse, a Type 6.0 would use the power of a megaverse, and so on.