Dyson Spheres Around White and Red Dwarfs: Calculating the Search ⚡ экспресс
Dyson spheres — hypothetical megastructures that capture all of a star's radiation — could point to highly advanced civilizations. The authors calculated how such spheres would look around white dwarfs (stellar remnants) and red dwarfs (small, long-lived stars). A sphere around a white dwarf would be cold and glow in the near-infrared, while around a red dwarf it would be warmer but at longer wavelengths. Increasing the sphere's radius lowers its temperature, but the total brightness stays the same — like wrapping a star in a thermal blanket that heats up but doesn't shine brighter. These data will aid the search for extraterrestrial intelligence in infrared sky surveys.
If you build a giant blanket around a star, you get a Dyson sphere. It absorbs all the radiation and glows in invisible heat rays. No such sphere has been seen yet, but astronomers know: to find it, look for this thermal glow.
Scientists have calculated how the blanket heats up around two types of stars: white dwarfs (cooled-down remnants of suns, whose nature was first described by Chandrasekhar) and red M-dwarfs (the most common, cool stars). The larger the blanket's radius, the cooler it is — this follows from the law discovered by Planck. An unexpected conclusion: near a dim white dwarf, the blanket will heat up more but glow faintly, while around a bright red dwarf, it will remain barely warm, yet shine with full power.
This can be detected with the James Webb Space Telescope: a Dyson sphere doesn't hide the star, it only shifts its light into infrared — invisible heat, discovered by Herschel. Methods of brightness measurement and spectral analysis will help spot these strange objects and, perhaps, find traces of extraterrestrial intelligence.
🎯 If you built a Dyson sphere around the Sun at the distance of Earth's orbit, its surface would have room temperature — about 300 K.
🎬 Giant spheres around stars have appeared many times in science fiction, for example, in the series 'Star Trek: The Next Generation' (episode 'Relics').