The Benefits and Harms of Transmitting Into Space

TL;DR

This paper evaluates the potential benefits and harms of Earth's radio transmissions into space, highlighting that deliberate messaging efforts are less detectable than existing terrestrial signals and discussing the uncertainties of extraterrestrial contact.

Contribution

It provides a comparative analysis of METI broadcasts versus terrestrial radio emissions, emphasizing the lower detectability of deliberate messages and exploring the ethical considerations of extraterrestrial contact.

Findings

METI broadcasts are less detectable than terrestrial radio emissions.

Terrestrial sources like radars are the strongest detectable signals.

Benefits of Earth's radio communication likely outweigh potential extraterrestrial harms.

Abstract

Deliberate and unintentional radio transmissions from Earth propagate into space. These transmissions could be detected by extraterrestrial watchers over interstellar distances. Here, we analyze the harms and benefits of deliberate and unintentional transmissions relevant to Earth and humanity. Comparing the magnitude of deliberate radio broadcasts intended for messaging to extraterrestrial intelligence (METI) with the background radio spectrum of Earth, we find that METI attempts to date have much lower detectability than emissions from current radio communication technologies on Earth. METI broadcasts are usually transient and several orders of magnitude less powerful than other terrestrial sources such as astronomical and military radars, which provide the strongest detectable signals. The benefits of radio communication on Earth likely outweigh the potential harms of detection by extraterrestrial watchers; however, the uncertainty regarding the outcome of contact with extraterrestrial beings creates difficulty in assessing whether or not to engage in long-term and large-scale METI.