Nikolaj Kardasev proposes to classify extraterrestrial civilizations based on their energy consumption: Type I, i.e. planetary (10^16W), Type II, i.e. stellar (10^26W), Type III, i.e. galactic (10^36W); we are Type 0.7; with the information in our possession in 2005 we believe that there are no Type 0.7 civilizations within 4000 light years, Type I within 40,000 light years (half a galaxy), Type II within 30 million light years (the entire Local Group and the hundreds of galaxies of the Virgo cluster) and that probably no Type III civilizations exist.
