Artificial Light or Heat

A technologically advanced civilization will likely emit heat and/or light as a product of industrialization. Civilizations which expand across the termperate surfaces of their worlds will probably employ nighttime artificial illumination, and as their energy needs increase may rely on orbital solar arrays to harvest sunlight beyond night's meridian. Conversely, civilizations which develop underground or in oceans may have no need for surface illumination, depending instead on geothermal or hydrothermal power and thus posing a greater challenge for remote sensing.

Industrialization also generates a proportional amount of waste heat, and urbanization can further raise temperatures, particularly when artificial surfaces fail to... More

A technologically advanced civilization will likely emit heat and/or light as a product of industrialization. Civilizations which expand across the termperate surfaces of their worlds will probably employ nighttime artificial illumination, and as their energy needs increase may rely on orbital solar arrays to harvest sunlight beyond night's meridian. Conversely, civilizations which develop underground or in oceans may have no need for surface illumination, depending instead on geothermal or hydrothermal power and thus posing a greater challenge for remote sensing.

Industrialization also generates a proportional amount of waste heat, and urbanization can further raise temperatures, particularly when artificial surfaces fail to efficiently dissipate sunlight or are impervious to precipitation, a climatological phenomenon known as the "urban heat island" effect. This excess thermal output is emitted as infrared radiation.

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Detectability

  • A sufficient amount of artificial light on the dark side of a spinning exoplanet is potentially observable in the planet's light signature.
  • Similarly, an unusual amount of waste heat, if observed in tandem with other indicators of industrialization, would be a potential indicator of a technologically advanced civilization.
  • More broadly, an unusually high amount of aggregate infrared radiation from a specific region of space could be a potential indicator of interplanetary industry.

Research

14-Aug-2021
Monthly Notices of the Royal Astronomical Society
15-Jul-2021
20-May-2021
2-Mar-2021
23-Oct-2020
International Journal of Astrobiology
18-Jul-2019
Bulletin of the American Astronomical Society
20-Dec-2018
27-May-2015
Astrophysical Journal
14-Apr-2015
Astrophysical Journal
5-Aug-2014
Astrophysical Journal
(14-Aug-2021)
Monthly Notices of the Royal Astronomical Society
(15-Jul-2021)
Thomas G. Beatty (20-May-2021)
Hector Socas-Navarro, Jacob Haqq-Misra, Jason T. Wright et al. (2-Mar-2021)
David Kipping, Adam Frank, Caleb Scharf (23-Oct-2020)
International Journal of Astrobiology
Jason T. Wright, Erik Zackrisson, Casey Lisse (18-Jul-2019)
Bulletin of the American Astronomical Society
NASA Technosignatures Workshop Participants (20-Dec-2018)
Eric J. Korpela , Shauna M. Sallmen , and Diana Leystra Greene University of California et al. (27-May-2015)
Astrophysical Journal
Roger L. Griffith, Jason T. Wright, Jessica Maldonado et al (14-Apr-2015)
Astrophysical Journal
J. T. Wright, R. Griffith, S. Sigurdsson et al (5-Aug-2014)
Astrophysical Journal