Drake's equation disagrees with sundowner's post.
Nc = N* fp ne fl fi fc fL
ne : number of planets per star that are capable of sustaining life
Question: For each star that has a planetary system, how many planets are capable of sustaining life?
Answer: estimates range from 1 to 2. This estimate needs to be substantiated.
If factor ne is close to zero then Nc is close to zero.
If factor ne is ZERO then Nc is zreo.
My post above attempts to estimate this factor.
The Drake equation "assumes" a number of planets capable of sustaining life without substantiating that assumption.
The dropdown in the calulator will only go down to .33 for a variable of ne.