| Term | Estimate | Calculation | Running total | |
|---|---|---|---|---|
| Number of stars in our galaxy | stars | = | stars | |
| |
||||
| Fraction of stars suitable for hosting planets with life |
% |
= | stars are suitable for life | |
| |
||||
| Fraction of stars with planets |
% |
= | stars have planets | |
| |
||||
| Fraction with habitable planets |
% |
= | habitable planets | |
| |
||||
| Fraction that develop life |
% |
= | worlds develop life | |
| |
||||
| Fraction that evolve intelligent life |
% |
= | worlds develop intelligent life | |
| |
||||
| Fraction that develop a high-tech civilization |
% |
= | intelligent species develop a high-tech civilization | |
| |
||||
| Fraction that are around now |
% |
stars with no habitable planets |
stars with habitable planets |
habitable planets with life |
planets that develop a high tech civilization |
high tech civilization is around now |