In astrobiology, there's a gap: the evolution of intelligence is barely studied. The author proposes noosemiotics—the science of noosignatures, meaning material or signal imprints of intelligence (from tools to radio broadcasts). It’s a ‘middle’ class between biosignatures (life) and technosignatures (technology). By studying artifacts on Earth, we can develop methods to search for intelligence in space, even if we can’t decode its meaning. Analogy: we're not just listening for a ‘ring’ from another mind, but also spotting its ‘handwriting’ on any surface.
Studying distant exoplanets, scientists look for signs of life — for instance, water and carbon — and signs of technology: radio signals, megastructures. But between these clues there is a yawning gap. If intelligence hasn't created machines or they've vanished, we won't notice it. A new approach suggests searching for noosignatures — any ordered imprints of a thinking being.
Noosemiotics, the science of such traces, gives clear criteria to distinguish them from natural chaos. Its first examples are terrestrial: stone tools, cave paintings. Applying these methods to spectroscopy of distant planets' atmospheres, we may notice what we previously missed. The most surprising twist: the most reliable noosignatures are not messages, but waste. A rubbish heap is visible from distant stars and needs no decoding.
🎯 The most noticeable noosignatures are not signals, but garbage: our civilization has already left a layer of plastic that will persist in geological deposits for millions of years.
🎬 In the Strugatsky brothers' novel 'Roadside Picnic', the Zone left by aliens is full of artifacts whose meaning is completely incomprehensible — these are typical noosignatures.