It's looking less likely that a swarm of comets or an "alien megastructure" can explain a faraway star's strange dimming.
The star (nicknamed "Tabby's Star," after its discoverer, Tabetha Boyajian) made major headlines last October when Jason Wright, an astronomer at Pennsylvania State University, suggested that it could be surrounded by some type of alien megastructure. A more likely idea — one that's far less exciting — is that the star is orbited by a swarm of comets. But scientists can't be sure either way.
Now, Bradley Schaefer, an astronomer at Louisiana State University, has probed the star's behavior over the past century by looking at old photographic plates. Not only does the star's random dipping date back more than a century, but it also has been gradually dimming over that period — a second constraint that makes it even harder to explain. [13 Ways to Hunt Intelligent Alien Life]
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