The Atlantic writes about The Most Mysterious Star in Our Galaxy. "Astronomers have spotted a strange mess of objects whirling around a distant star. Scientists who search for extraterrestrial civilizations are scrambling to get a closer look."
Kepler is a space telescope, looking at the same patch of the sky over time. The idea is to track the strength of the light coming from 145,000 stars. If they dim, on a regular basis, it's probable that planets are passing in front of the star (aka transiting the star). It's our main source of new exoplanet discoveries. The longer it looks the better the chance of spotting planets with larger orbits.
In 2011, several citizen scientists flagged one particular star as “interesting” and “bizarre.” The star was emitting a light pattern that looked stranger than any of the others Kepler was watching. The light pattern suggests there is a big mess of matter circling the star, in tight formation.
The article points to a paper, here's the abstract:
Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20% level. The dipping activity can last for between 5 and 80 days. We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, and Fourier analyses of the Kepler light curve. We determine that KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period ∼ 0.88 d, that exhibits no significant IR excess. In this paper, we describe various scenarios to explain the mysterious events in the Kepler light curve, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps orbiting a normal main-sequence star, we conclude that the scenario most consistent with the data in hand is the passage of a family of exocomet fragments, all of which are associated with a single previous breakup event. We discuss the necessity of future observations to help interpret the system.
So, okay, comets. The article then says:
Jason Wright, an astronomer from Penn State University, is set to publish an alternative interpretation of the light pattern. SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Wright and his co-authors say the unusual star’s light pattern is consistent with a “swarm of megastructures,” perhaps stellar-light collectors, technology designed to catch energy from the star. “When [Boyajian] showed me the data, I was fascinated by how crazy it looked,” Wright told me. “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.”
So sure, maybe. Regardless, I expect to see lots of BuzzFeed like articles saying we've discovered an ancient alien civilization. Nope, just one crazy hypothesis that might fit the data. Obviously more research is being done (because that's what scientists do) and we'll find out more in a few years. Until then, don't believe we've discovered aliens building a Dyson Sphere.