Drake Equation Calculator

The Drake Equation was formulated by astronomer Frank Drake in 1961 to estimate the number of active, communicative extraterrestrial civilizations in our galaxy. It multiplies together seven factors: the rate of star formation, the fraction of stars with planets, the number of habitable planets per system, the fraction where life develops, the fraction that becomes intelligent, the fraction that develops detectable technology, and how long those civilizations emit detectable signals.

Drake's original 1961 estimate was around 10 civilizations. Using more modern astronomical data (like the discovery that most stars have planets), some optimistic estimates go as high as 15,600,000, while pessimistic ones suggest we might be alone.

If the Drake Equation suggests there should be many alien civilizations, why haven't we found any evidence of them? This contradiction is the Fermi Paradox, named after physicist Enrico Fermi who famously asked 'Where is everybody?' Proposed solutions range from the Great Filter hypothesis to the Zoo hypothesis (aliens are watching but not interfering).