Comets May Have Caused 'Alien Megastructure' Star's Strange Dimming

A faraway star's mysterous dimming was most likely caused by comets, a new study suggests — though it doesn't rule out the much-ballyhooed possibility of an "alien megastructure" in the system. Observations by NASA's planet-hunting Kepler space telescope revealed that the star KIC 8462852, which lies about 1,500 light-years from Earth, dipped in brightness dramatically in 2011 and 2013, dimming by up to 22 percent. Such deep brightness dips puzzle astronomers, who have advanced a numb