> we'd see an object that was more than 200 million miles across (ie the cloud of orbitals) that is producing much of that energy as infrared. It would stick ou

> we'd see an object that was more than 200 million miles across (ie the cloud of orbitals) that is producing much of that energy as infrared. It would stick out like a sore thumb. Unfortunately large objects emitting a lot of total energy in infrared don't stick out like a sore thumb. It's very difficult to distinguish a Dyson swarm from a Dyson swarm sized ball of Dyson swarm temperature gas and dust, which is a reasonably commonplace phenomenon. Indeed for one of the simpler construction methods, a dyson swarm may essentially be a big ball of dust where each mote is a solar energy collector. Further, over long time scales without active maintenance you'd expect dyson swarms to break down into literal clouds of gas and dust. While dyson swarm candidates might be good places to focus other SETI experiments like radio telescopes, it's unlikely that the thermal signature of the swarm alone would ever be unambiguously artificial.