The average number of stars formed per year in the galaxy.

The fraction of stars that have planets (between 0 and 1).

Average number of planets that can support life per star that has planets.

The fraction of habitable planets on which life actually develops (between 0 and 1).

The fraction of inhabited planets that develop intelligent life, thus civilization (between 0 and 1).

The fraction of civilizations that develop a technology releasing detectable signs of their existence into space (between 0 and 1).

Length of time for which technological civilizations release detectable signals into space (in years).

The number of civilizations in the galaxy with which communication might be possible.

The average number of detectable civilizations appearing each year in the galaxy.

Civilization lifetime standard deviation.

Simulation speed in year(s) per second.