Atmospheric pollution could be the sign of advanced extraterrestrial civilization
This study is the first time pollution has been examined as a possible technosignature.
Artist’s illustration of a technologically advanced exoplanet. The colors are exaggerated to show the industrial pollution, which otherwise is not visible.
Credits: NASA/Jay Freidlander
Nitrogen dioxide is part of a group of gaseous air pollutants produced due to road traffic and other fossil fuel combustion processes. In the lower atmosphere (about 10 to 15 kilometers or around 6.2 to 9.3 miles), NO2 from human activities dominate compared to non-human sources. Therefore, observing NO2 on a habitable planet could potentially indicate the presence of industrialized civilization.