N / ASA scientists have described an ingenious way to detect signs of thriving alien civilizations on distant planets.
In a paper this week, they suggested that greenhouse gases on other worlds could provide evidence that we are not alone in the universe.
That’s because industrial agriculture, run by little green men, would release plumes of exhaust gas into the atmosphere.
Just like on Earth, the gases would change the composition of the planet’s air and act as a detectable signature of life.
These “technosignatures” could be picked up by powerful telescopes here on Earth and help guide our search for ET.
It’s a new perspective on the search for so-called biosignatures – natural substances that scientists look for as indicators of life.
“The search for technosignatures is a continuation of the search for biosignatures,” the researchers write in their article.
“It includes the idea of looking for spectral evidence of technology in the atmospheres of exoplanets.”
The team, which also included astronomers from Nasa’s Goddard Space Flight Center, investigated whether nitrogenous gases found on Earth could act as effective technosignatures on other planets.
They reasoned that in order to grow on other worlds, plants would likely need water and carbon cycles, as well as the presence of nitrogen in the soil.
All emerging civilizations would presumably work to grow crops by applying fertilizers – like manure – to the soil.
On Earth, the use of such fertilizers has increased levels of chemicals such as ammonia and nitrous oxide in the atmosphere.
The presence of these gases on alien worlds could therefore indicate that alien farmers are working below.
“The combined presence of these gases in the atmosphere of a habitable planet could serve as the technology’s remotely detectable spectral signature,” the researchers wrote.
To test their theory, the team calculated how far Earth’s nitrogenous gases would be detectable.
They concluded that today’s concentrations of ammonia and nitrous oxide are difficult to detect.
However, if our planet’s population increased to at least 30 billion, the resulting increase in greenhouse gases would be high enough for telescopes to detect.
It is possible that scientists will seek technosignatures as they broaden their search for potential alien worlds.
Of course, the presence of greenhouse gases wouldn’t prove extraterrestrial life anywhere – they could always be the by-product of the planet’s natural processes.
Scientists have previously suggested scanning distant planets for non-natural waste products such as chlorofluorocarbons (CFCs), which can remain in the atmosphere for tens of thousands of years.
Famed Harvard University astrophysicist Avi Loeb has suggested light pollution as a possible sign of technological civilizations.
A number of powerful new telescopes, including the recently launched James Webb Space Telescope, are turning their sights on exoplanets in hopes of discovering elusive biosignatures.
This includes oxygen produced by photosynthesis by plants and certain microbes.
The research was published in the preprint journal archive.
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https://www.thesun.ie/tech/8650420/nasa-scientists-clue-spot-alien-farms-planets/ Nasa scientists unveil HUGE clue that could help discover ‘alien farms’ on distant planets