technosignals

Technosignals are measurable indicators of technology that could originate from extraterrestrial civilizations. The term, used in the search for extraterrestrial intelligence (SETI), distinguishes signals of intelligent activity from biosignatures, which indicate life. Technosignals can be electromagnetic or non-electromagnetic, and may arise from distant communications, intentional beacons, or large-scale astroengineering.

Electromagnetic technosignals include narrow-band or pulsed radio transmissions, broad-band modulated signals, and optical laser pulses that could be detected by telescopes. Non-electromagnetic technosignatures encompass signs of energy harvesting, waste heat from megastructures, atmospheric pollutants, or unusual planetary transits or light curves suggestive of artificial constructs.

Search strategies involve scanning for artificial-sounding signals in radio and optical bands, measuring persistence, repetition, and uniqueness to natural sources. They face challenges such as distinguishing natural astrophysical phenomena and human-made radio frequency interference. Verification typically requires independent observations, multi-wavelength corroboration, and statistical assessment of significance.

While no technosignature has been confirmed, the field of technosignals broadens the scope of astrobiology and informs instrument development and observational campaigns. It emphasizes methodological rigor, data-sharing, and international collaboration in the ongoing search for evidence of intelligent life beyond Earth.