Fast radio bursts from deep space that last a few milliseconds have scientists puzzled although they were first detected a decade ago.
The largest theory is that they are the ‘exhaust’ of alien space probes. This has been suggested by the Astrophysical Journal Letters. It put forward a solar-powered transmitter with a surface area twice the size of the Earth.
Meantime the world’s largest radio telescopes, such as the Parkes Observatory in New South Wales, record these flashes leading to fuelling speculation about their source or meaning.