Il Post sets out three hypotheses to explain why extraterrestrials stay silent
The Italian outlet weighs the zoo hypothesis, a limit on interstellar connections and the prospect of artificial extraterrestrials as answers to an unexplained cosmic silence.
The farthest human-made object from Earth is Voyager 1, launched in 1977, past the edge of the solar system since 2012 and now a little over 25 billion kilometres away. It still transmits, but its power reserves are nearly spent and one day it will fall silent. Il Post uses that benchmark to frame the question running through its series on extraterrestrial life: where humans cannot travel in person, they send objects that may outlast them.
Against that silence, the Italian outlet sets out three explanatory proposals. The oldest is the zoo hypothesis, advanced in 1973 by John Allen Ball, an astrophysicist at Harvard University, in an article of that name published in Icarus, a journal of planetary sciences. Ball's argument, as Il Post recounts it, is that civilisations more advanced and older than our own might deliberately avoid all interaction, leaving the part of the universe we inhabit a sort of protected area.
A second line of argument, as Il Post frames it, rests on a study hypothesising that interstellar connections become at some point unsustainable for possible extraterrestrial civilisations. A third asks whether extraterrestrials might themselves be artificial intelligences, lacking the characteristics of living organisms but also their limits — a proposition the outlet presents as a science-fiction hypothesis with various implications. Voyager 1 supplies the counter-image: a thing built by humans that may keep travelling and outlast its makers.
None of the three is offered as a finding. Ball's formulation is a theoretical proposal from 1973, and Il Post describes the other two as hypotheses rather than observations. The accounts differ in their implications, but nothing in them identifies a test capable of distinguishing among the explanations, and no confirmed signal or artefact is cited. Until a detection attributable to a non-human civilisation exists, the competing accounts of the silence remain proposals rather than conclusions.