Related to all
star systems A in our galaxy, the number
N_{X} of a set
of star systems belonging to a certain spectral class is
given:
12.2.3.1 Equation 
N_{x}
= A · F_{X} 
A = (100 – 300)·10^{9}
= Number of Suns in the Galaxy
F_{X} is the
probability of the occurrence of a set of stars belonging
to a certain spectral class. There are
13 spectral classes (chapter 12.1)
There is the set of sunlike G stars, with a yellow
spectral color and the probability of F_{s}
= 0,28 = 7:25.
There is the set of red dwarfs, i.e. M stars with a
redorange spectral color and a probability of F_{RZ}
= 0,7 = 7:10.
The two spectral classes G and M make up 98%
of the total stars in the galaxy.
The spectral types O, B, A, F, K, i.e. the blue,
bluewhite, white, whiteyellow and orange spectral
colours make up about 1% of the total
stars.
The brown dwarfs and the red giants, i.e. the spectral
classes L, T, Y, R, N, S, also make up 1%
of the total stars.
According to equation 12.1.1, the set of civilizations of
a set of stars, each caused by a spectral class, applies.

N_{zx}
= N_{x}
· F_{ph }·
F_{k}
· F_{Liz}
= A · F_{x}
· F_{ph }·
F_{k}
· F_{Liz} 
Equation 12.2.2 gives the total number of
civilizations in the galaxy in sum across all
spectral classes:

N_{zivGal}
= ∑ N_{zx}
= A·∑ (F_{x}
· F_{ph}
· F_{k }·
F_{Liz}) 


12.2.3.2
Equation 

F_{p} = 0,014.4 = 201:14.000 star systems with
planets
F_{h} = 0,016.6 = 10:603 planets in habitable
zones
By definition
8.2.1: F_{ph}
= F_{p} · F_{h}
F_{ph} = 201:14.000 · 10:603
F_{ph}
= 1:4.200
By equation
12.5.1 applies:; F_{k }=
F_{gae}_{ }
with 0,001 <
F_{k}
< 0,004.7 and
0,000.927 < F_{gae} <
0,004.672_{
}The probability F_{gae}
for the similarity of the Earth is of the same order of
magnitude as the observation probabilitiesF_{k}.with
which all models are equivalent.
By definition
6.3.2: F_{Liz}
= F_{L} · F_{i}
· F_{z}
Then equation 12.2.3.2 can also be written like this:
12.2.3.3 Equation 

According to equation 4.1.4.5, the probability of
life applies:
In particular:
There are n = 8 components
called for life to become possible.
It applies to
the single probability: f_{j}
= 1:72
This can also cause 8 failures.
For weighting factors, approach 4.1.4.6 applies.: a_{j}
= 1
Thus, the chance of life arises F_{L}=
1:(n+1) = 1:9.
According to equation 5.2.2.5, the probability of
intelligence applies:
In particular:
There are k = 13 causes listed
that can destroy life on earth globally.
It applies to
the single probability:: f_{j}
= 1:182
Only every 14th planet on which there is life could
produce a conscious species.
For the weighting factors, the approach 5.2.2.6 applies: b_{j}
= 1
Thus, the chance of intelligence arises F_{i}=
1:(n+1) = 1:14.
This results in the number of civilizations, of one
civilization level, in the galaxy:
12.2.3.4 Equation 

According to equation 6.2.4, the following probability
can be established for one civilization
level:
Technological
civilizations form the levels 6,7
and 8. Therefore the total probability for a
technological civilization is:
F_{z} = 14.400/7.301 · (1:36+1:49+1:64)
F_{z}= 405.225/3.218.741 = 1:7,943 ¤ 1:8
This results in the number of technological
civilizations in the galaxy:
12.2.3.5 Equation 

Adapted to the model used so far:
A, F_{x},
F_{ph}, F_{k} are empirically determined factors that are
expected to increase in the future.
For
the factors F_{L}
and F_{i}
there is enough leeway to capture any set of
prerequisites and therefore try different models.
There are n
components so that life can be made weighted with the a_{j}.
There are k components that can prevent
the intelligence weighted with the b_{j}.
The probability of F_{z}
can be applied to a level of civilization as well as a
number of stages of civilization. m is
the stage of civilization and
&sum m is a set of civilization
levels.
Equations 12.2.3.4 and 12.2.3.5 include all the cosmic,
planetary, and evolutionary influences that a species is
exposed to until it has developed a technological
civilization.
Equations 12.2.3.4 and 12.2.3.5 build a matrix of
variables into which all impacts, from development to
civilization, can be assessed and estimated.
