deletions | additions       diff --git a/Now_we_have_some_constraints__.tex b/Now_we_have_some_constraints__.tex  index f1d6013..8bab522 100644  --- a/Now_we_have_some_constraints__.tex  +++ b/Now_we_have_some_constraints__.tex 
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Ok I know I know, there is \href{http://en.wikipedia.org/wiki/Roswell_UFO_incident}{Roswell}... the \href{http://en.wikipedia.org/wiki/Wow!_signal}{WOW signal}... \href{http://en.wikipedia.org/wiki/List_of_reported_UFO_sightings}{UFO} sightings... Well, I am not going into that. I will just state that the most economical explanations for all the aforementioned cases have nothing to do with E.T. and that at this time there is no clear evidence that prove we had contact with alien life. Let's use the \href{http://bit.ly/KDLFp6}{Occam's razor} and throw away the conspiracy spoon.  Back to us. The Fermi Paradox implies that $N$ (number the number  of communicative civilizations $N$  in our Galaxy) the Galaxy  is probably small\footnote{There are some solutions to the Fermi Paradox that do not require $N$ to be small, for a nice review have a look at this \href{http://waitbutwhy.com/2014/05/fermi-paradox.html}{great post}}. Our revised version of the Drake Equation then leaves two\footnote{Of course the third option is that both $f_i$ and $L$ are small} interesting alternatives: \begin{enumerate} \item $f_i$ is a small number. That is\textbf{ life is common in the Universe, but intelligent life is not}.  \item $L$ is a small number. Intelligent \textbf{life do not spend much time in the communicative phase}.  \end{enumerate}