← Start with a question
Investigation
If intelligent life is rare, how could anyone ever find us?
The galaxy is enormous, old, and mostly quiet. Two equations frame the problem from opposite directions, and neither of them gives an answer — they organize the ignorance.
Astronomy · Statistics · Astrobiology
The evidence
Suggested reading path
01Established KnowledgeHow Would We Find Alien Life?Silence is a measurement of our searching, not of the sky. Two centuries of listening covered a startlingly small slice of an enormous search space.02Established KnowledgeThe Drake Equation: Dividing an Impossible QuestionN = R* × fp × ne × fl × fi × fc × L. It is not a physical law. It is a disciplined way of splitting one unanswerable question into seven we can argue about separately.03Established KnowledgeL Is the Frightening Term: The Twenty-Light-Year BubbleL is not how long life lasts, or intelligence, or even civilization. It is how long a civilization stays detectable — and a civilization can grow quieter as it grows more advanced.04Plausible ExtrapolationThe Keen Equation: Overlap, Not AbundanceNK = Np × fl × fi × ft × fd × fg × fp × fr × fs. Drake asks how many are out there. Keen asks how many could possibly ever know about us.05Established KnowledgeWhy Arecibo Was a Red Laser Pointed at One TreeThe strongest deliberate message humanity ever sent was three minutes long, aimed at one target, and will not arrive for twenty-five thousand years.
Questions to think about
Keep arguing
- — Which Drake factor would you most want measured, and what would it take?
- — Humans have been detectable for roughly a century. What does that imply about our odds of overlapping with anyone?
- — Is the silence evidence of absence, or evidence about detection?
Continue
Other investigations
Biology · History · Ethics · Literature
Who has the right to rewrite a human being?
Physics · Measurement · Philosophy of science
How can the Servator hang there without pushing anything?
Biology · Cognition · Philosophy
What if an octopus is intelligent in a way we cannot measure?
Astrobiology · Ecology · Literary criticism
What do they want — and why do we keep guessing?