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The Fermi paradox: why haven’t we found aliens?

Imagine arriving at a vast gathering and finding every room quiet. Is nobody there—or have you only just opened the first door?

AliensOnly editorial · 4 November 2026 · 4 minute read

The question behind the name

The Fermi paradox concerns the apparent tension between the possibility of other technological civilisations and our lack of confirmed contact. It is associated with physicist Enrico Fermi and a conversation in 1950.

Its force depends on assumptions. If civilisations arise often, last long enough and spread between stars, why don’t we see an obvious sign of them? Alter any of those assumptions and the puzzle changes.

Three questions that are easy to confuse

A positive answer to the first would not automatically answer the other two. A world of microbes would be an extraordinary discovery, but it would not send a radio message.

What could explain the silence?

Proposed answers include rare technological life, civilisations that do not persist or expand, and signals we cannot yet recognise. These are possibilities to investigate, not an established menu of facts.

Think of a search as a set of choices: where to look, when to look and what to count as a promising signal. A search that finds nothing constrains the possibilities it could have detected. It cannot automatically eliminate every possibility outside its scope.

Time makes the question harder

For a simple illustration, imagine two communities sending a brief greeting once, at different times. Both could exist without either receiving the other’s greeting during its listening period. That thought experiment is not evidence about real civilisations; it shows why timing belongs in the question.

Distance adds another delay. In our calculator, a destination 100 light-years away receives a light-speed message after 100 years. Even with an immediate response, the reply reaches its sender 200 years after transmission.

What would move the discussion forward?

A useful explanation needs more than an appealing story. Ask what observation would support it, what could count against it and whether a different explanation predicts the same thing.

For any headline about a possible discovery, look for the measurement behind it. Was the observation repeated? Have other researchers checked it? Is a dramatic interpretation necessary, or merely one possibility?

Stay with the question

You don’t have to choose between certainty that we are alone and certainty that visitors are already here. It is reasonable to find the question compelling while leaving the answer open.

The next time someone offers a simple solution to the Fermi paradox, try this: identify the assumption doing the most work. Is it about how life begins, how technology develops, how long it lasts, or how we search?