Have astronomers found any evidence of Dyson spheres around other stars?

The answer

A Dyson sphere (or swarm), conceptualized by physicist Freeman Dyson in 1960, would be a megastructure surrounding a star to capture most of its energy output. Such a structure would be detectable by its excess infrared emission - absorbed starlight re-radiated as waste heat. In 2024, researchers analyzing data from Gaia, 2MASS, and WISE infrared surveys identified seven M-dwarf stars within 900 light-years showing unexplained mid-infrared excess consistent with partial Dyson sphere models. Published in the Monthly Notices of the Royal Astronomical Society, the findings require follow-up to exclude natural explanations like warm dust disks, extreme debris belts, or background galaxy contamination. The famous Tabby's Star (KIC 8462852), whose irregular dimming of up to 22% sparked Dyson sphere speculation in 2015, was later attributed to dust clouds. SETI programs including Breakthrough Listen now include systematic infrared surveys for waste heat signatures in their search strategies.