February 22, 2021 To find alien life in our universe, scientists have considered searches for optical lasers or even giant energy-harvesting structures known as Dyson spheres. Now they’re suggesting a more mundane sort of search, a hunt for air pollution in exoplanet atmospheres.
Artist’s concept of an advanced alien civilization on a distant exoplanet. A new study suggests that some alien societies might pollute their planets’ atmospheres, much as we on Earth do. If so, we might be able to detect this alien pollution. Image via NASA/ Jay Freidlander.
Early SETI – Searches for Extraterrestrial Intelligence – focused solely on looking for artificial radio signals. Much of SETI still leans that way, but the search has now broadened to include the idea of searching for technosignatures (signs of advanced technologies) from alien civilizations, living on distant planets. Scientists are now discussing and even beginning to hunt for signals from, for example, optical lasers o
The Best Way to Find Aliens on Other Worlds May Be to Search For Signs of Their Smog
14 FEBRUARY 2021
The Universe is a big place, so scientists are keen to narrow down their search for alien life – maybe by looking for radio signals, or hospitable climates, or huge megastructures. Now another sign of alien life is under consideration: atmospheric pollution.
If there are alien civilisations out there, the hypothesis goes, then their activities and industries may have produced pollution just like ours have. That pollution could be something we could spot in our scans of deep space.
A new study suggests nitrogen dioxide gas (NO2) could indicate life on other planets: It can be produced from burning fossil fuels, as well as from lighting, volcanoes, and other biological, non-industrial sources.
Ravi Kopparapu, who works at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and is the lead author of the study, explained this further, “On Earth, most of the nitrogen dioxide is emitted from human activity combustion processes such as vehicle emissions and fossil-fueled power plants,” adding, “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 an industrialized civilization.”
With more than 4,000 exoplanets found so far, experts are eager to find out if any of them host other civilizations but since they are so far away from us, the only way we can search for signs of life is with powerful telescopes that can find out what’s in their atmospheres.
NASA says we should search for aliens by looking for their pollution
New research funded by the space agency suggests next-generation telescopes might be able to see the emissions of far-flung smokestacks. Listen - 02:51
In this artist s illustration, the colors of an exoplanet are exaggerated to show industrial pollution, which otherwise isn t visible. NASA/Jay Freidlander
We know the galaxy is home to plenty of potentially habitable exoplanets, but to determine whether anything is actually living on these worlds scientists hope to spot some sign of life, a so-called biosignature or technosignature. New research out of NASA s Goddard Space Flight Center in Maryland suggests searching for alien pollution as one such indicator.
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.