We’ve seen some stories this year that at first glance look like they might be pointing in the direction of an as yet undiscovered alien civilization.
In one case there was the radio signal from the HD164595 system. This is a Sun-like star located a little less than 100 light years from Earth. Previously, this star was discovered to have a probable gas giant planet orbiting it. Thus, the similarity of this star system to ours and the discovery of the radio signal would have us wonder whether this star system has another as yet unseen Earth-like planet with an intelligent civilization. I feel the need to say that the radio signal has not been confirmed by any other observatory, nor has there been any new signal from this star system. Also, the amount of energy needed for such a signal over such a distance is staggering. So, though we shouldn’t give up, we also shouldn’t make this star our best hope for finding intelligent life.
Another interesting case is that of KIC8462852, or Tabby’s Star, nicknamed for one of the astronomers who discovered strange variations in the light from this star. Examination of the light from this star shows that it is gradually dimming over as much as perhaps the last 100 years. In addition, there was a very sudden dimming during the last set of observations of this star by the Kepler satellite. What could be causing this? One enterprising astronomer suggested that it could be a Dyson sphere being slowly constructed around the star at first, and then being rapidly constructed towards the end of the last time we looked. A Dyson sphere (named for the first proposer of this idea, Freeman Dyson) is essentially a swarm of light collecting satellites that are put into orbits around a star and form a shell like structure around the star (although Dyson did not suggest they actually form a solid shell). They can then transmit this energy elsewhere and have an enormous energy harvest from the star. Though this is more likely in the end to be explained by something more prosaic, and as suggested by others, a dust disk forming around the star and blocking it out,with perhaps planetary collisions adding to further dimming , it’s certainly interesting enough to keep an eye on!