8 Biggest, Weirdest Mysteries In Space

4. That "Alien Megastructure" Keeps Getting Weirder

Remember that "alien megastructure" that hit the headlines because some astronomers thought it might be some kind of Dyson Sphere? The humble little star KIC 8462852 became world famous, that is, before its strange erratic flickering was disappointingly put down to a cloud of comets.

The story took another twist, however, when it was observed that, as well as flickering, the star appeared to be getting slowly dimmer - something which couldn't be explained with current models. Its light dipped by as much as 20% but isn't consistent with the normal dimming associating with planetary transit.

Further observations have revealed that the star undergoes three types of dimming: the flickering initially observed, a relatively slow decline taking place over the last 100 years, and another more rapid dimming that occurred over a few hundred days.

Explanations range from the fantastical to the mundane, but the truth is that, at the moment, we just don't know what's going on.