Do you remember that so-called “alien megastructure” that made the news last year before being debunked? It’s now sending out weird signals, drawing attention once again to the enigmatic celestial object, New Scientist is reporting.
Back in October 2015, as reported at the time by the Atlantic, the Kepler Space Telescope began compiling some unusual data from a distant star in the constellation Cygnus. Lovingly named KIC 8462852 (nicknamed “Tabby’s Star”), the star emitted a weird signal pattern that baffled astronomers.
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Scientists and backyard astronomers alike noticed that the light from Tabby’s Star dimmed periodically. That’s not unusual; when a star appears to “dim” (to observers on Earth, that is), that usually means there is a planet passing in front of it. That’s precisely how scientists have confirmed the existence of most of the known exoplanets, which are planets that observe a star other than our own. As of this writing, about 3,500 exoplanets have been discovered.
— The SETI Institute (@SETIInstitute) August 9, 2016
But the dimming of Tabby’s Star was so profound and so erratic that scientists quickly ruled out the possibility of an exoplanet orbiting the star. But just what is it? As writer Ross Andersen explained, there’s a “big mess of objects” around the star, but its provenance remains mysterious.
“There is this mess of objects circling it. A mess big enough to block a substantial number of photons that would have otherwise beamed into the tube of the Kepler Space Telescope. If blind nature deposited this mess around the star, it must have done so recently.”
Jason Wright, an astronomer for Penn State University, first raised the possibility that an “alien megastructure” was orbiting Tabby’s Star.
“It looked like the kind of thing you might expect an alien civilization to build.”
At this point, it bears noting that Wright never actually said there was an “alien megastructure” circling the star. In fact, Wright himself said that the alien hypothesis was just one of many and also the least likely.
“Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.”
Nevertheless, the words “alien megastructure” created headlines, and the story of whatever was circulating Tabby Star became the subject of headlines — that is, until the story died down once it became obvious that there probably isn’t and never has been — any sort of alien craft surrounding the star.
Except now the signals coming from the star are getting even weirder. Looking at the data going back a century, scientists have determined that Tabby’s Star is dimming in three ways. First, by comparing photo templates going back as far as 1890, scientists postulate that the star has dimmed by 15 percent over a hundred years. Secondly, over the course of a thousand days — the first thousand days that Kepler observed it — it decreased in brightness by 0.34 percent per year. Third, the star dimmed by another 2.5 percent over the next 200 days.
So what’s going on over there? Further evidence that an alien megastructure is near the star?
Astronomer Josh Simon is quick, once again, to point out that there could be any number of explanations for what’s going on around Tabby’s Star, including possibilities that science has yet to figure out. Or it could be aliens.
“Once you’re invoking arbitrary advanced aliens doing something with technology far beyond ours, then there isn’t very much that can’t be explained. But we don’t really want to resort to that until we exhaust all of the possible natural explanations we can think of.”
About all scientists can do for now is keep observing and hope that the star gives them something useful. To that end, a crowdfunding project has raised $100,000 to secure the use of the Las Cumbres Observatory Global Telescope Network for a year. Maybe by the time a year is up, the “alien megastructure” hypothesis will either be conclusively proven or disproven.
[Image via Angela Harburn/Shutterstock]