Reconsidering macro-artefacts in SETI searches
Abstract The observation of macro-artefacts at interstellar distances offers an alternative search paradigm to SETI programs such as radio astronomy and laser detection. Potential artefacts range from space infrastructure deployed by advanced technological civilizations to deliberate attempts to use artefacts as signals and biomarkers of intelligent life. Passive observations of macro-artefacts could overcome problems with active transmission messaging such as temporal and spatial constraints. Artefacts could be detected without being spatially resolved by telescopes. Spectral analyses could yield evidence of disruption of the natural electromagnetic spectra of stars by artefacts. Some artefacts could generate diffraction and interference patterns uncharacteristic of natural phenomena. Thus, detecting macro-artefacts is potentially feasible with current astronomical infrastructure. The construction of large macro-artefacts could be achieved with technological and industrial capabilities that are roughly equivalent to present-day Earth. Thus, the accessibility of macro-artefacts for both transmission and reception can be reconsidered as potentially equivalent to conventional SETI strategies.