The Universe - The Seager Equation

Professor Sara Seager is an expert on the search for exoplanets.
Professor Seager has revised the Drake equation, to focus on the presence of any alien life, rather than civilisations.

The Seager Equation can be used to estimate how many planets with detectable signs of life might be discovered in the coming years. 

The Seager equation looks like this:

N = N*FQFHZFOFLFS

N = the number of planets with detectable signs of life
N* = the number of stars observed
FQ = the fraction of stars that are quiet
FHZ = the fraction of stars with rocky planets in the habitable zone
FO = the fraction of those planets that can be observed
FL = the fraction that have life
FS = the fraction on which life produces a detectable signature gas

The Drake Equation assesses our chances of finding radio-capable civilizations.

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