Particle.news
Download on the App Store

Bayesian Study Finds Hidden Nearby Alien Signals Unlikely, Urges Galaxy-Wide SETI Surveys

A Bayesian analysis argues six decades of non-detections point to rare, distant, long-lived technosignatures.

Overview

  • EPFL physicist Claudio Grimaldi posted a new arXiv study modeling present-day detectability given undetected technosignature contacts since 1960.
  • High odds of a nearby detection would require implausibly many past contacts, in some cases exceeding the number of potentially habitable planets within a few hundred to a few thousand light-years.
  • Detection prospects improve mainly for long-lived emissions spanning several thousand light-years, yet only a few detectable signals are expected across the Galaxy at any time.
  • The conclusions apply to both omnidirectional signatures and tightly targeted beacons, with short-lived signals further reducing detectability.
  • The paper recommends prioritizing deeper, wider Milky Way surveys over narrow, local searches, noting that optimistic alternatives would demand unlikely local clustering or a recent sudden rise in emitters.