Experts pointed out that the star's light was winking in and out of view in a way that could presumably possibly be the result of some massive orbiting alien structure. The scientists didn't really think that our space telescopes had caught sight of an "alien megastructure," but there's no harm in hoping.
Since then, the Search for Extraterrestrial Intelligence (SETI) institute has turned its radio telescopes to the strange star — and they haven't heard any of the radio signals we'd expect from the goings-on of an intelligent civilization.
A cluster of comets had been floated as one possible explanation. Now, in a study published in the Astrophysical Journal Letters, Massimo Marengo of Iowa State University (along with his doctoral student Alan Hulsebus and former student Sarah Willis, now a researcher at the Massachusetts Institute of Technology’s Lincoln Laboratory) suggests it's the most likely one.
Marengo and Co.'s work didn't actually rule out an alien megastructure, but it did rule out other, more likely explanations — like massive planetary or asteroid collisions. Looking at the star in infrared light didn't reveal the hot dust one would expect from such violent activity. That makes the most likely (non-alien) explanation a set of cold comets — ones that have been orbiting the planet for a while, causing different levels of dimming based on their assorted sizes and transit periods.
"This is a very strange star," Marengo said in a statement. "It reminds me of when we first discovered pulsars. They were emitting odd signals nobody had ever seen before, and the first one discovered was named LGM-1 after 'Little Green Men.'”
Pulsars turned out to be very weird — but they weren't aliens, either.
"We may not know yet what's going on around this star,” Marengo said. “But that's what makes it so interesting."