The equation 5.3.1
for "Earth 2" with an intelligent species can
be extended to:
Equation 6.3.1 shows the number of intelligent species that may have technology and have reached a development level greater than 2. Equation 6.3.1 can be simplified a little further. To do this, you have to look at the probability factors. The following are known:
If you only look at "Earth 2", you can still establish a probability for a civilization:
F_{z}
must be adapted to the quantities of civilization to be
considered, which will become apparent in the following
sections.

176 sides, of them 64 in Color 76 pictures 11 tables Production and publishing: Books on Demand GmbH, Norderstedt ISBN 9783752855241 Price: 22 Euro 
