Astronomers have discovered a star that shows possible signs of having an alien structure around it.
The structure could be caused by a neighboring star pulling a string of comets close to it, but “this would involve an incredibly improbable coincidence,” one of the astronomers said. See here: Astronomers may have found giant alien ‘megastructures’ orbiting star near the Milky Way.
Another possibility is that the scientists have found a Dyson sphere or Dyson cluster, “a hypothetical megastructure that encompasses a star and captures most or all of its power output.”
Dyson spheres or clusters, if they exist, are built by civilizations far more advanced than ours.
Here is a study on the phenomenon: Planet Hunters X. KIC 8462852 – Where’s the flux?
And another article: The Most Mysterious Star in Our Galaxy.