DESPITE OVER 50 YEARS OF EFFORT, THE Search for Extraterrestrial Intelligence (SETI) enterprise has yet to detect any telltale signs of sentient life beyond Earth. But exciting news of an anomalous star 1,400 light-years from Earth has raised new hopes that we are not alone in the galaxy after all. Using data collected by the Kepler space telescope, astronomers discovered that the distant star—KIC 8462852—flickers in an unusual way, as if some unknown celestial bodies were intermittently obscuring it. Of the roughly 150,000 stars within view of the Kepler telescope, KIC 8462852 is the only one that glimmers in this odd fashion.1 Since it has been observed over the past few years, KIC 8462852 has dimmed dramatically, at times dropping in brightness as much as 22 percent.2 Moreover, the recorded dips have not been regular, but uneven and unpredictable. Tabetha Boyajian announced these amazing findings that she and members of Planet Hunters— a citizen’s science program launched at Yale University—discovered in a paper recently published in the Monthly Notices of the Royal Astronomical Society.3
A number of hypotheses have been advanced to explain the anomalous activity of the star. Conceivably, the dips in light could be occasioned by an orbiting planet, but even a Jupiter-sized planet would dim this type of star by only 1 percent as it transited across. Furthermore, the irregular flickering associated with the star would not be consistent with a planet making a regular orbit, which would produce predictable dimming. Perhaps fragments from a planetary collision could be responsible for the dimming light, but such events are so rare that we would not expect Kepler to pick up such activity based on probabilities.4 Finally, the star could be surrounded by an accretion disk of dust and rubble that has not yet agglomerated into planets or been gobbled up by the star itself. Such an explanation would be convincing if the star were young, but KIC 8462852 appears to be mature. As Jason Wright, a professor of astronomy at Penn State University, noted, the star is moving too fast to have formed recently, as it fails to show any infrared signs of any big disk that is normally associated with the material that could cause such dips in brightness.5
