In 2015, The Atlantic first reported that astronomers had discovered some tantalizing information about a distant star in the Milky Way, located about 1,300 light-years from Earth in a swan-shaped constellation called Cygnus. The star itself, slightly bigger than our sun, seemed pretty ordinary as far as stars in the universe go. But every now and then, the light of the star appeared to dim and brighten.
This wasn’t the weird part. Astronomers look for faint dips in brightness in their search for exoplanets around other stars all the time. The dimming means that something is passing in front of a star and blocking some light from reaching Earth. Telescope observations have discovered thousands of exoplanets in this way.
The weird part about this star was the behavior of those light fluctuations. The flickering seemed almost random. Some dips in light lasted a few hours, while others lasted for days or weeks. The light dimmed by 1 percent at some times, a change that would typically suggest the presence of a Jupiter-sized exoplanet around the star. But at other times, the light would dim by more than 20 percent, a drop that suggested something much more massive was passing by.
The star’s sporadic dimming stumped astronomers, who dubbed it “the most mysterious star in the universe.” They proposed several natural theories, like a transiting comet. When none seemed to fit the bill, they started considering something else. Could the object passing in front of this star, blocking out the light, be a swarm of alien megastructures built by an advanced civilization?