deletions | additions       diff --git a/Parameters.tex b/Parameters.tex  index 629c6f9..ed8c27d 100644  --- a/Parameters.tex  +++ b/Parameters.tex 
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As we discussed this number is now known: in average, there is one planet orbiting every star in the Universe \citep{2013ApJ...764..105S,2012Natur.481..167C} which means $f_p \approx$ 1  $n_e$ Is the \textbf{fraction of Earth-like planets}.   As from last year we also know this factor! Earth-like planets are very common. Statistically speaking at least 1 in 5 planets around Sun-like stars could potentially support life \cite{Petigura_Howard_Marcy_2013}. $n_e \approx$ 0.2 So the product of the first 3 terms is now well established and is, using a conservative approximation, of order 1.   $N =\underbrace{\overbrace{R}^{\approx10} \times \overbrace{f_p}^{\approx 1} \times \overbrace{n_e}^{\approx 0.2}}_{\sim 1} \times \underbrace{f_l \times f_i \times f_c \times L}_{?}$  We can then simplify the Drake equation and re-write it in its "2014 form" as:  $N \approx f_l \times f_i \times f_c \times L$