Posted: 10 Aug 2014 04:30 AM PDT
Looking for aliens? Scan the skies for pollution
The search for extraterrestrial life, popularly known
as SETI, has traditionally focused on searching for life in the universe by
scanning the skies for electromagnetic radiation, like radio waves. A better
way to search for extraterrestrial civilizations might be to look for
industrial pollution, argues Sara Imari Walker, an assistant professor in
ASU's School of Earth and Space
Exploration and the Beyond Center for Fundamental Concepts in
Science, in a Future Tense article for Slate magazine.
Industrial pollutants like the climate-altering
chlorofluorocarbons (CFCs) that human industries produce could potentially be
detected from hundreds of light years away. Pollution may be a more reliable
sign of advanced civilizations than radio waves, which, judging by our own
technological development, are only a temporary stepping stone to more advanced
communications technology.
The Earth, which once broadcast a high volume of radio
waves into space, is becoming increasingly "radio quiet" as we shift
toward digital communications. If extraterrestrial civilizations are like us,
they will only be using radio waves for 100 years or so, which seems like a
long time, but on a cosmic scale is "hardly the blink of an eye."
Henry Lin of the Harvard-Smithsonian Center for
Astrophysics, which has led the way in championing the hunt-for-pollution
approach, has questioned whether discovering pollution in the farthest reaches
of space would really be a sign of intelligent life.
Lin wonders if "civilizations more advanced than
us ... will consider pollution as a sign of unintelligent life since it's not
smart to contaminate your own air." Walker's perspective is that "our
methods to search for extraterrestrial intelligence are an intimate reflection
of ourselves."
In a historical moment where pollution and climate change are in the forefront of our global consciousness, it's not such a surprise that we are searching the skies for other civilizations in a similar situation.
"Hopefully," writes Walker, "we will one day enter a phase of human technological development where we will possess the insights to look for 'greener' little green men."
In a historical moment where pollution and climate change are in the forefront of our global consciousness, it's not such a surprise that we are searching the skies for other civilizations in a similar situation.
"Hopefully," writes Walker, "we will one day enter a phase of human technological development where we will possess the insights to look for 'greener' little green men."
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