Could an advanced civilization build a shell around a star?

The answer

In 1960, physicist Freeman Dyson proposed that a sufficiently advanced civilization might build a megastructure surrounding its star to capture virtually all its energy output - about 4 × 10²⁶ watts for a Sun-like star. A rigid shell is physically implausible, but a 'Dyson swarm' of billions of orbiting solar collectors could achieve the same result. Such a structure would be detectable as a star that dims irregularly and radiates excess infrared heat. Tabby's Star (KIC 8462852) briefly excited scientists with unusual dimming patterns, but natural explanations now seem more likely. No confirmed Dyson structures have been found.