The industrial chemicals released into the atmosphere are a sign of civilization.
If everything is going well, the James Webb Space Telescope, launched in December, will travel farther into the universe this summer than ever before.
Unlike its predecessor, the Hubble Telescope, Webb can make direct observations of distant exoplanets and perhaps even life on their surface.
For example, plants reflect infrared light when in contact. It can appear as a red border in the pictures taken by Webb, thus revealing the life lurking on the planet.
Webbia can also be utilized in the search for intelligent space life, U.S. researchers suggest in their study. It has been approved for publication in the Planetary Science Journal.
For example, humanity can be detected from space by waste heat and artificial lighting.
However, the easiest way to identify our handprint is from the industrial chemicals released into the atmosphere. According to scientists, this kind of pollution is exactly what Webb should look for on exoplanets as well.
Blue Astrobiologist at the Marble Space Research Institute Jacob Haqq-Misra and his colleagues focused especially on freons, a chemical compound composed of chlorine, fluorine, and carbon.
They have been used since the 1930s, for example, in refrigerators, fire extinguishers and as a propellant for shower cans.
On the surface of the earth, these compounds are harmless, but when released into the atmosphere, they destroy ozone. In the 1980s, scientists discovered that freon emissions had caused a huge gap in the earth’s ozone layer.
If similar signs were found in the atmosphere of some exoplanet, there is almost certainly an industrialized civilization like humanity behind it.
Pollution however, observation with a telescope is not quite simple. If the planet’s parent star is too bright, its radiation can obscure the signs of pollution below it.
According to researchers, it is worth looking at the red dwarfs, which are the dimmest of the stars.
One potential candidate is Trappist-1, 40 light-years away, orbiting several Earth-sized exoplanets in an ideal life zone.
The problem is that red dwarf stars are not the best hosts for life. When they are young, they are very unstable and rush powerful eruptions around them, which can destroy the budding life on the orbiting planets.
Published in Science 5/2022.
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