Not Just Radio Messages: NASA Expands the Search for Extraterrestrial Cultures

A new project will search for technosignatures that might indicate the presence of advanced alien civilizations.

Perovo Solar Power Station
The 100-megawatt Perovo Solar Power Station in Ukraine is one of the largest photovoltaic facilities in the world. SETI researchers theorize that if alien civilizations were to use even larger solar facilities, scientists on Earth could pick up tell-tale signs from the reflected light.

For decades, radio telescopes have been eavesdropping on the cosmos, hoping to detect alien signals. Now NASA is expanding the scope of that search: For the first time, it has awarded a grant to a SETI project that will search for technosignatures other than radio signals. “Our imagination is limited by what we have accomplished as a technological civilization,” says Abraham Loeb, the Frank B. Baird, Jr., Professor of Science at Harvard University. “Whereas radio communication was a new technology 70 years ago, we can now imagine the signatures of other advanced technologies.”

The next generation of telescopes, such as the James Webb Space Telescope, will offer researchers the means to detect subtle biosignatures in the atmospheres of exoplanets. But life doesn’t necessarily mean intelligence, and SETI researchers at the Center for Astrophysics | Harvard & Smithsonian and the University of Rochester say they can detect alien industrial civilizations with the telescopes currently available.

For instance, solar panels “absorb light up to a certain wavelength and reflect the rest,” says Loeb. “This leads to a spectral edge in their reflected light, which is distinguishable from the ‘red spectral edge’ produced by vegetation....Such panels would be particularly useful for tidally locked planets that show the same side to the host star at all times. A civilization might want to put solar panels on the permanent dayside of the planet and use the power harvested there to illuminate and heat the cold nightside.”

The NASA grant provides a total of $285,000 for two years—and potentially thousands of light years.

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This story is a selection from the September issue of Air & Space magazine

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