Nearly a year after first making headlines around the world, “Tabby’s star” is still guarding its secrets.

In September 2015, a team led by Yale University astronomer Tabetha Boyajian announced that a star about 1,500 light-years from Earth called KIC 8462852 had dimmed oddly and dramatically several times over the past few years.

These dimming events, which were detected by NASA’s planet-hunting Kepler space telescope, were far too substantial to be caused by an orbiting planet, scientists said. (In one case, 22 percent of the star’s light was blocked. For comparison, when huge Jupiter crosses the sun’s face, the result is a dimming of just 1 percent or so.) [13 Ways to Hunt Intelligent Alien Life]

Boyajian and her colleagues suggested that a cloud of fragmented comets or planetary building blocks might be responsible, but other researchers noted that the signal was also consistent with a possible “alien megastructure”  perhaps a giant swarm of energy-collecting solar panels known as a Dyson sphere.