A Failure of Serendipity: the Square Kilometre Array will struggle to eavesdrop on Human-like ETI

TL;DR

The paper argues that the SKA will likely struggle to detect extraterrestrial signals similar to human technology due to Earth's increasing radio quietness, making accidental detection of ETI highly improbable.

Contribution

It introduces a Monte Carlo simulation to assess the likelihood of detecting human-like ETI signals, highlighting the challenges posed by technological evolution and signal leakage reduction.

Findings

Detection probability is approximately 10^{-7} for human-like civilizations.

Earth's increasing radio quietness significantly reduces the chance of detecting ETI.

Dedicated communication methods greatly increase detection likelihood.

Abstract

The Square Kilometre Array (SKA) will operate in frequency ranges often used by military radar and other communications technology. It has been shown that if Extraterrestrial Intelligences (ETIs) communicate using similar technology, then the SKA should be able to detect such transmissions up to distances of ~100 pc (~300 light years) from Earth. However, Mankind has greatly improved its communications technology over the last century, dramatically reducing signal leakage and making the Earth "radio quiet". If ETIs follow the same pattern as the human race, will we be able to detect their signal leakage before they become radio quiet? We investigate this question using Monte Carlo Realisation techniques to simulate the growth and evolution of intelligent life in the Galaxy. We show that if civilisations are "human" in nature (i.e. they are only "radio loud" for ~100 years, and can only detect each other with an SKA-like instrument out to 100 pc, within a maximum communication time of 100 years), then the probability for such civilisations accidentally detecting each other is low (~10^{-7}), much lower than if other, dedicated communication techniques are permissible (e.g. optical SETI or neutrino communication).