Do aliens use CFCs?

The search for extraterrestrial intelligence, or SETI, began in the early 20^th century. The technologies available to us today allow us to consider further research. Some telescopes such as the Allen Telescope Array (ATA) make it possible to examine exoplanets¹ or red dwarfs².

 

So far, the main research on extraterrestrial life has focused on biosignatures: that is, the detection of gases such as methane or oxygen that could indicate that life could flourish in other solar systems.

 

The idea of ​​examining technosignatures (or technological signatures) has been gaining ground for a few years, as this document published in 2018 by NASA indicates. This time, scientists have proposed examining traces which could have been left in the atmosphere of the planets, indicating industrial or technological activity. On Earth, for example, technosignatures can be illustrated by artificial lights, the presence of buildings or constructions (the Chinese wall is visible from space).

 

Humanity has also changed the observable characteristics of the Earth in a significant way through atmospheric pollution. The example of CFCs has been studied in various articles showing that such technosinatures can be detected by the James Webb Telescope. Solar panels may also exist on other planets and be observed. Indeed, the light reflected from a planet has a very particular wavelength. Light reflected or absorbed by the sensors would produce different wavelengths, and thus be observable from a distance.

 

NASA has just awarded a grant to a team of researchers from the University of Rochester, and the Harvard-Smithsonian Center for Astrophysics.The study entitled "Characterizing Atmospheric Technosignatures" will mainly focus on the search for solar panels or pollutants.

 

¹ Exoplanet: planet outside the solar system

² Red dwarf: small massive low temperature star