Why Cosmic Silence Proves Nothing
People often say: 'SETI has been searching for 60 years and found nothing — so nobody is out there.' But this is a logical error. To understand why, we need to calculate how much of the sky we have actually searched and what that means statistically.
This simulation uses the Monte Carlo method: we randomly place N civilizations throughout the Galaxy and check whether any of them fall within the field of view of our radio telescopes. By running thousands of random trials, we build up a statistical picture of our chances of detection under various assumptions.
The Numbers Are Sobering
SETI has surveyed less than 0.1% of the sky in the relevant frequency ranges. Even if there are 1,000 communicating civilizations in the Milky Way, our probability of having detected one by now is only about 0.63%. That is like searching one room in a mansion with a thousand rooms and concluding the building is empty. The absence of evidence is not evidence of absence — at least not yet.
What Would It Take?
Adjust the sky coverage parameter to explore what it would take to make a definitive statement. For 95% confidence that we would have detected at least one civilization (assuming 1,000 exist), we would need to survey roughly 3% of the sky — thirty times more than we have covered so far. Next-generation facilities like the Square Kilometre Array (SKA) will dramatically increase our coverage, potentially surveying the entire sky at unprecedented sensitivity. Until then, the cosmic silence remains statistically consistent with a Galaxy teeming with life.