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Searching for evidence of alien life using ‘technosignatures’

A NASA grant will enable a group of researchers to develop a new approach to the search for extraterrestrial intelligence (SETI) by looking for evidence of technological activity.

“SETI has always faced the challenge of figuring out where to look,” Adam Frank, a professor of physics and astronomy at the University of Rochester, said in a statement. “Which stars do you point your telescope at and look for signals? Now we know where to look. We have thousands of exoplanets including planets in the habitable zone where life can form. The game has changed.”

Scientists have discovered more than 4,000 planets outside our solar system
Scientists have discovered more than 4,000 planets outside our solar system. In the search for intelligent life, astrophysicists including the University of Rochester’s Adam Frank are seeking the physical and chemical signatures that would indicate advanced technology. NASA/JPL-Caltech

Most previous work in the search for alien life has focused on two aspects: Firstly, biosignatures, which are direct indicators of life such as microbes, or secondly, radio signals, which are assumed could be a commonality produced by many forms of intelligent alien life. The new approach is to look for “technosignatures,” which are indicators of technological activity.

Although the potential breadth of alien technology is huge, “there are only so many forms of energy in the universe,” Frank said. “Aliens are not magic.”

The researchers will begin by looking at two specific technosignatures, for solar panels and pollutants. Searching for evidence of use of solar power makes sense because stars are some of the biggest sources of energy in the universe, so it’s likely that an advanced alien race would harness this power in some way. It may be possible to detect indicators like light reflected from solar panels, which would have particular properties which would make it identifiable.

As for pollutants, we are able to identify the chemical composition of the atmospheres of exoplanets, so searching these atmospheres for evidence of pollution would suggest the presence of industry and technology. We could search for the presence of artificial gases like chloroflourocarbons (CFCs), which used to be used on Earth as refrigerants and in aerosols, and which do not occur naturally.

With this grant, the team will begin by identifying the wavelength bands in which you might find evidence of these two technosignatures, which could be used when investigating exoplanets.

“My hope is that, using this grant, we will quantify new ways to probe signs of alien technological civilizations that are similar or much more advanced to our own,” said Avi Loeb, Professor of Science at Harvard.

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