Alien megastructures would likely self-destruct before we spot them

If advanced alien civilisations are building vast satellite swarms designed to harvest a star’s energy, we should be able to see them – so why haven’t we? One answer might be that these structures, known as Dyson spheres, will likely destroy themselves before we can spot one, according to new calculations.

The idea of structures that can siphon off most of the energy from their stars was first proposed by physicist Freeman Dyson in the 1960s. Astronomers have theorised that these structures, if they exist, should give off a telltale signature…