2016/03/29 by David Kipping, David M. Kipping, Alex Teachey · 42 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Broadband #Exoplanet #Laser #Optics #Physics #Planet #Planetary Science and Exploration #Search for extraterrestrial intelligence #Solar System #Space Science and Extraterrestrial Life #Starlight #Stars #Transit (satellite) #astro-ph.EP #astro-ph.IM #physics.pop-ph
paper · pdf · doi:10.1093/mnras/stw672
published in Monthly Notices of the Royal Astronomical Society 459(2), 1233-1241 (Oxford University Press) · 10 pages, 6 figures, accepted in MNRAS
arxiv created 2016/03/29 · openalex publication_date 2016/03/30 · arxiv updated 2016/04/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The transit method is presently the most successful planet discovery and characterization tool at our disposal. Other advanced civilizations would surely be aware of this technique and appreciate that their home planet's existence and habitability is essentially broadcast to all stars lying along their ecliptic plane. We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission. Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits. We estimate that humanity could cloak the Earth from Kepler-like broad-band surveys using an optical monochromatic laser array emitting a peak power of ∼30 MW for ∼10 hours per year. A chromatic cloak, effective at all wavelengths, is more challenging requiring a large array of tunable lasers with a total power of ∼250 MW. Alternatively, a civilization could cloak only the atmospheric signatures associated with biological activity on their world, such as oxygen, which is achievable with a peak laser power of just ∼160 kW per transit. Finally, we suggest that the time of transit for optical Search for Extraterrestrial Intelligence (SETI) is analogous to the water-hole in radio SETI, providing a clear window in which observers may expect to communicate. Accordingly, we propose that a civilization may deliberately broadcast their technological capabilities by distorting their transit to an artificial shape, which serves as both a SETI beacon and a medium for data transmission. Such signatures could be readily searched in the archival data of transit surveys.