At first, scientists posited that the star's intermittent shining was due to comet swarms, but that seemed far less plausible when evidence emerged that it had been irregularly dimmed for over a century. But some have claimed the historical evidence is too unreliable to support a clear decreasing trend, pointed out Gizmodo.
So earlier this year, researchers Ben Montet of CalTech and Joshua Simon of the Carnegie Institute chose to study a few years of data on KIC 8462852, nicknamed Tabby's Star, gathered by the very precise Kepler space telescope. Ultimately, they explain in an unpublished report, the light decline is significant, not replicated by other nearby stars and is most likely not due to a comet cloud.
Back in October 2015, The Washington Post noted that scientists have mostly dismissed the theory that alien structures are blocking light from Tabby's Star. Mostly. Aliens should always be the last hypothesis considered, a Penn State University professor told the Post, but it would explain the flickering. Sadly, no new information was revealed in the Louisiana State University researchers' report, so the dimming remains a mystery. In their own cryptic but measured words from the paper, "No known or proposed stellar phenomena can fully explain all aspects of the observed light curve."