An artist's concept showing the Wide-field Infrared Survey Explorer, or WISE spacecraft, in its orbit around Earth.
Look at a picture of the Earth at night, and the world appears to be, quite literally, glowing. Now, scientists are starting to look for signs of advanced alien civilizations by the glow given off by technology used to harvest the energy from a star or even an entire galaxy.
Theoretical physicist and mathematician Freeman Dyson first proposed the idea that advanced alien civilizations might develop technology to encircle a star and harvest most of its power, a structure now known as a Dyson sphere. If these objects do exist, astronomers might be able to detect the waste heat they produce using telescopes that peer into space using infrared light.
"The main point," Dyson told LiveScience, "is looking for aliens who don't want to communicate. My question was, 'How do you look for silent aliens?' They have to radiate away their waste heat. The only way to do that is to radiate lots of infrared radiation." [13 Ways to Hunt Intelligent Aliens]
Now, astronomers at Pennsylvania State University are starting to narrow the search for Dyson spheres. But the search has only just begun, and may take hundreds of years, Dyson said. Finding Dyson spheres isn't inevitable, but "it's certainly possible," he said.
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