Three months ago, news broke that a giant "alien megastructure" could exist around a bizarre-looking star 1,500 light-years away. Read more here: Alien Mega 'Dyson Sphere' Structure Found Surrounding A Star claims Astronomers
What makes this star, KIC8462852, so bizarre is the drastic changes in light we see from it over time.
An alien megastructure, called a Dyson swarm, was suggested as one explanation for what scientists have observed, but the most likely reason astronomers came up with was comets — a giant family of them.
Surprise: It's probably not comets
"The comet-family idea was reasonably put forth as the best of the proposals, even while acknowledging that they all were a poor lot," Schaefer told New Scientist. "But now we have a refutation of the idea, and indeed, of all published ideas."
To make his discovery, Schaefer had to dig deep down into the astronomy archives at Harvard. It turns out, astronomers have data on KIC8462852 dating back as far as 1890.
By analyzing over 1,200 measurements of this star's brightness taken from 1890 through 1989, Schaefer found that the irregular dimming of KIC8462852 has been going on for over 100 years. Schaefer published his findings in the online preprint server arXiv.org.
What's more, he explains in his paper that this "century-long dimming trend requires an estimated 648,000 giant comets (each with 200 km diameter) all orchestrated to pass in front of the star within the last century," which he said is "completely implausible."
So what is it?
At the same time, he's also reignited the possibility that the source could be an alien megastructure that an advanced alien civilization has been slowly building over time. One thing's certain for Schaefer: The bizarre dimmings are probably caused by a single, physical mechanism that's undergoing some type of ongoing change.
"The century-long dimming and the day-long dips are both just extreme ends of a spectrum of timescales for unique dimming events, so by Ockham's Razor, all this is produced by one physical mechanism," Shaefer said in his paper. "This one mechanism does not appear as any isolated catastrophic event in the last century, but rather must be some ongoing process with continuous effects."
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