Life in the Universe. Stuff. Lots of stuff. 100 billion+ star systems in the Milky Way New exoplanets being discovered every day 100 billion+ galaxies in observable universe Carbon can arrange in many, many ways…
Number of “Contactable” Civilizations = NHP x flife x fciv x fnow
NHP = Number of habitable planets in the galaxy
flife = Fraction of planets that are habitable
fciv = Fraction of planets that can communicate
fnow = Fraction of planets that have a civilization now
So… where are the aliens?