259
Two surveys of millions of stars in our galaxy have revealed mysterious spikes in infrared heat coming from dozens of them. Astronomers say this could be evidence for alien civilisations harnessing energy from their stars by using a vast construction known as a Dyson sphere – although they can’t fully rule out more mundane explanations.
First proposed in the 1960s, Dyson spheres are hypothesised structures that could surround entire stars to absorb their energy, a possible means by which advanced aliens might…