dyson_sphereOver fifty years ago, physicist Freeman Dyson proposed an awesome, if slightly insane, idea: That an advanced alien civilization might construct a massive, energy-harvesting sphere around its star, and bunk up inside. Scientists have never given up on Dyson spheres—we’ve even conducted a few legitimate searches for their infrared heat signatures. Now, physicists Ibrahim Semiz and Salim Ogur may have an explanation for why we can’t seem to find the megastructures. If Dyson spheres exist, they’re probably a lot smaller than we thought. Since Dyson first proposed his massive space habitats, scientists have tried to imagine how such structures could physically work. By and large, researchers have focused on Dyson spheres encircling Sun-like stars. But this scenario poses a few major, and perhaps insurmountable, problems. For starters, such a sphere would have to be built at a distance of roughly 1 AU, the same distance between the Earth and the Sun. Read Article