The birth and death phases of stars, for example, are associated with heavy dust clouds that give off an infra-red signal which might resemble the swarm of artificial satellites constituting a Dyson sphere.

ECONOMIST: Is it time for a new approach to finding extraterrestrials?

Any civilisation that has built a Dyson sphere will have to have been around for a long time, of course and in the very long run its star will start to change in unpleasant ways, ballooning to form a red giant.

ECONOMIST: Is it time for a new approach to finding extraterrestrials?