
Analogous to
the previous Special Basic Model we can
generalize the equations 3.1.1 and 3.3.4 for
habitable "Earths 2" in sunlike
systems so that they apply to general star
systems with habitable, earthlike planets: 


8.3.1 Equation 
N_{hex}
= N_{phx}
· F_{gae}
N_{hex}
= A · F_{X }·
F_{ph }·
F_{gae} 
The number of N_{hexGal}
of all star systems with habitable, earthlike
planets in the galaxy is then the sum of all spectral
classes:
8.3.2 Equation 
N_{hexGal}
= ∑ N_{hex}
= A · ∑ (F_{X }·
F_{ph }·
F_{gae}) 
Assuming that the
other star systems, i.e. not sunlike stars, also have
the same or similar planetary distribution, it is
possible to estimate how many systems with habitable
"Earths 2" could exist.
8.3.3 Approach 
In star systems that are not
sunlike, there are probably the same or similar
distributions, for earthlike habitable planets,
as in sunlike systems. 
The number N_{hexGal
}of all star systems with habitable, earthlike
planets in the galaxy (∑ F_{x} = 1), is
approximately equivalent to:
8.3.4 Equation 
N_{hexGal}
= ∑ N_{hex}
≈ A · F_{ph }·
F_{gae} 
Inserting all values
(F_{e} = 0.1) into equation 8.3.4:
N_{hexGal1} = (100300)·10^{9} ·
1:4200 · 1:69
N_{hexGal1} = 345,065 –
1,035,196 habitable „Earth 2“
Inserting all values (F_{e} = 0,01) into equation
8.3.4:
N_{hexGal2} = (100300)·10^{9} ·
1:4200 · 1:691
N_{hexGal2} = 34,456 –
103,370 habitable „Earth 2“
The two results can then be summarized to the following
statement::
8.3.5 Theorem 
There
could be between 34,000 and 1,035,000 Earths 2 in
our galaxy. 


8.3.6 Theorem 
There
could be a maximum of up to 1 million
"Earths 2" in our galaxy. 
The probability for habitable,
earthlike planets in any star system, in the galaxy, is
then:
:
8.3.7 Definition 
F_{hexGal}
= F_{ph }·
F_{gae}
F_{hexGal}
= F_{p }·
F_{h }·
F_{g }·
F_{a }·
F_{e} 
F_{hexGal} = F_{ph }· F_{gae}
F_{hexGal} = 1:4200 · (1:69–1:691)
F_{hexGal}
= 1:289,800 – 1: 2,902,200
Only every 289,800  2,902,200th star
system produces an earthlike planet, in the habitable
zone.
It is left to the reader for practice to make the
calculations for planets with life and intelligence
himself. Otherwise, see the table at the end of the book
(page 137).
