The search for alien life and advanced civilization elsewhere other than our home planet might be through finding industrial pollution in Earth-like planets, The Astrophysical Journal stated. A particularly advanced civilization might intentionally pollute the atmosphere to high levels and globally warm a planet that is otherwise too cold for life.
It is possible to spot the fingerprints of certain pollutants under ideal conditions, which would offer a new approach in the search for extra-terrestrial intelligence (SETI), the study by Harvard-Smithsonian Center for Astrophysics (CfA) noted. "People often refer to ETs as 'little green men,' but the ETs detectable by this method should not be labeled 'green' since they are environmentally unfriendly," said co-author Avi Loeb, a professor of science at Harvard University.
Two kinds of chlorofluorocarbons (CFCs) - ozone-destroying chemicals used in solvents and aerosols could probably get detected through NASA's upcoming James Webb Space Telescope (JWST). "The researchers calculated that JWST could tease out the signal of CFCs if atmospheric levels were 10 times those on Earth," Indo-Asia News Service reported. "There is one big caveat to this work. JWST can only detect pollutants on an Earth-like planet circling a white dwarf star, which is what remains when a star like our Sun dies."
However, an instrument beyond JWST, a next-next-generation telescope, will be required to find pollution on an Earth-like planet orbiting a Sun-like star. While searching for CFCs could ferret out an existing alien civilization, it could also detect the remnants of a civilization that annihilated itself, the researchers noted, adding that some pollutants last for 50,000 years in Earth's atmosphere while others last only 10 years.
In a panel discussion held at NASA headquarters in Washington, D.C., recently, experts outlined NASA's road map to the search for life in the universe, an ongoing journey that involves a number of current and future telescopes, IANS reported. "Sometime in the near future, people will be able to point to a star and say: That star has a planet like earth," said Sara Seager, a professor of planetary science and physics at the Massachusetts Institute of Technology in Cambridge, Mass.
The study appeared online in The Astrophysical Journal.
