Reported elsewhere but I’ll link to Phil Plait’s blog about the story here: Did Astronomers Find Evidence of an Alien Civilization? (Probably Not. But Still Cool.)
A star – the titular KIC 8462852 – has produced some very strange observations that are difficult to explain right now but do present some intriguing (with care) possibilities. Most likely, of course, are natural ones that we’re not able to observe thanks to the distance involved (around 1500 light years) but there’s an unlikely-but-appealing argument for something a little more unnatural too.
The observations are dips in the star’s light output, the means by which we typically detect planetary transits. As a rule these are periodic and the drop in starlight is a tiny percentage as planets are considerably smaller than the solar bodies they orbit. In KIC 8462852’s case the drops are irregular, sometimes dip slowly then rise quickly, and in a few cases dip by huge amounts (22%).
Look at our own civilization. We consume ever-increasing amounts of power, and are always looking for bigger sources. Fossil, nuclear, solar, wind… Decades ago, physicist Freeman Dyson popularized an interesting idea: What if we built thousands of gigantic solar panels, kilometers across, and put them in orbit around the Sun? They’d capture sunlight, convert it to energy, and that could be beamed to Earth for our use. Need more power? Build more panels! An advanced civilization could eventually build millions, billions of them.
But it raises an interesting possibility for detecting alien life. Such a sphere would be dark in visible light, but emit a lot of infrared. People have looked for them, but we’ve never seen one (obviously).
Which brings us back to KIC 8462852. What if we caught an advanced alien civilization in the process of building such an artifact? Huge panels (or clusters of them) hundreds of thousands of kilometers across, and oddly-shaped, could produce the dips we see in that star’s light.
The odds are low, but it’s a big universe out there. More observations needed.