No alien life has yet been found in space, but a new study has uncovered ‘telltale’ signs of an inhabited planet.
Researchers at the University of California, Riverside (UCR) found that greenhouse gases like those emitted on Earth would indicate that a distant world has been terraformed — or artificially altered.
Characteristics of methane, ethane and propane, along with gases made of nitrogen and fluorine or sulfur and fluorine, could indicate life forms that use technology, because the gases are only created through production.
Scientists ran simulations on a hypothetical planet and found that NASA’s James Webb Space Telescope (JWST) could detect the gases as easily as ozone on Earth.
Alien life has yet to be found in space, but a new study has uncovered a ‘telltale’ sign of an inhabited planet
UCR astrobiologist and lead author of the study Edward Schwieterman said: ‘For us, these gases are bad because we don’t want to increase warming.
“But they would be good for a civilization that might want to avoid an impending ice age or form an otherwise uninhabitable planet in their system, as people have proposed for Mars.”
The five gases proposed by the researchers are used on Earth in industrial applications such as making computer chips.
Researchers chose to simulate a planet in the TRAPPIST-1 system because it is home to seven known rocky words and is one of the most studied planetary systems.
They used the Planetary Spectrum Generator (PSG), a model designed to synthesize and retrieve data about a planet’s atmosphere and surface.
The team simulated the five gases on the hypothetical planet and calculated how many observations JWST would need to detect them using its Mid-Infrared Instrument (MIRI), which sees wavelengths from 5 to 12 micrometers.
MIRI has both a camera and a spectrograph, which separates the incoming light based on its frequency and records the resulting spectrum.
MIRI also has sensitive detectors that allow it to see red-shifted light from distant galaxies, newly forming stars, faintly visible comets and objects in the Kuiper Belt.
The study showed that JWST was able to detect greenhouse gases as easily as Earth’s ozone.
Researchers from the University of California, Riverside (UCR) found that greenhouse gases like those emitted on Earth would mean a distant world has been terraformed or artificially altered
Scientists ran simulations on a hypothetical planet and found that JWST could detect the gases in just five flybys as easily as ozone on Earth.
And the system revealed that JWST detected the gases with just five passes for high concentrations such as 100 parts per million (ppm).
Another advantage of searching for the proposed greenhouse gases is that they are exceptionally long-lived and can persist in an Earth-like atmosphere for up to 50,000 years.
“They don’t need to be refilled too often to maintain a hospitable climate,” Schwieterman said.
Other members of the research team echoed Schwieterman’s enthusiasm about the possibilities of finding signs of intelligent life, but also about how much closer current technology has brought us to that goal.
Daniel Angerhausen of the Swiss Federal Institute of Technology said: ‘Our thought experiment shows how powerful our next generation of telescopes will be.
“We are the first generation in history to have the technology to systematically search for life and intelligence in our galactic neighborhood.”