Five Ways to Look for ET in 60 Seconds

The Drake equation almost always appears as a single multiplication. That's wrong by construction: every factor has orders-of-magnitude uncertainty, and propagating the uncertainty changes the answer qualitatively. The Monte Carlo runs 10⁴ samples over your prior cube and returns the posterior on N — including P(N < 1), the probability humanity is alone in the Milky Way.

If N is small, almost all of the survival probability along the path from non-life to galactic civilisation must collapse somewhere. Where matters enormously: a filter behind us (abiogenesis, eukaryogenesis) is reassuring; a filter ahead (industrial collapse, alignment failure) is not. The tool walks the eight Hanson stages and computes the implied joint probability against your N from step 1.

If they exist, the cheapest way to find them used to be a narrowband carrier in the hydrogen window. Six decades and ~10⁵ targets later: nothing. The sensitivity calculator turns transmitter EIRP, distance, dish area, system temperature, integration time, and bandwidth into a detection floor. Sliding distance out shows how dramatically the assumed transmitter power matters.

Optical photons carry ~10⁵× more energy than 1.4 GHz radio, so a single-shot ns laser pulse can outshine the host star photometrically in its instant. The detection physics is sky-background-limited, not receiver-noise-limited — the sensitivity curve has a different shape than radio. APF Breakthrough Listen, NIROSETI, and the proposed ESO Optical SETI 2040s programme are the empirical anchors.

A Kardashev-II civ captures stellar luminosity and re-radiates it at the radiator temperature; the spectral signature shifts from optical to mid-IR. G-HAT surveyed ~10⁵ galaxies for the integrated stellar-light deficit + IR excess. The tool tells you how much panel mass a given swarm coverage actually needs — and where you cross the asteroid-belt budget, the Mercury budget, and the "this isn't engineering, it's geophysics" boundary.

The most uncomfortable answer to the silence: maybe an old enough civ is waiting. The Landauer floor scales with temperature, and the CMB is cooling on cosmological timescales; a sufficiently long nap buys ~10³⁰ extra irreversible operations per joule. Bennett, Hanson & Riedel (2019) push back: today's universe already has cold reservoirs, so the gain is illusory. Both arguments live in the tool; the user picks who they believe.