The Tabby’s Star anomalies were eventually explained as a combination of an accretion disk and odd stellar geometry brought on by the star’s high rate of spin and resultant gravitational darkening …
There was a lot more information in the download, and Koenig waded through it. He wasn’t familiar with much of it.
In the early twenty-first century, the Kepler space telescope had continuously monitored the light coming from some 150,000 stars in a small section of Cygnus; planets orbiting those stars would periodically block a tiny percentage of the light, causing dips in the stars’ brightness.
That period, from 2009 through 2015, was a heady one of exploration and discovery, as thousands of exoplanets, worlds outside of Sol’s domain, were found, and Humankind became aware of the fact that the Milky Way alone might contain 40 billion worlds like Earth. Out of all of those target stars, however, only one had showed a light curve as bizarre as one sun at the very edge of the target area: KIC 8462852. Light dips were frequent, sharp, and aperiodic—behaving like large numbers of huge objects orbiting their star “in tight formation,” as one astronomer put it. One particular object did seem to have a regular period. The first time it was spotted, it obscured 15 percent of the star’s light. The second time, 750 days later, it obscured 22 percent of the light.
Twenty-two percent? A super-Jupiter, the largest world possible, typically obscured about 1 percent of the light from its star as it passed in front of the star’s disk. To cause that big of a drop in the light output of the star, the eclipsing object would have to be so large it covered nearly a quarter of the star’s face. This could not be a planet, so what the hell was it?
Dozens of theories were fielded—possible natural explanations, including huge dust clouds, masses of perturbed comets, and colliding planets. None worked very well. The system was too old to have dust clouds or accretion disks, the chances of finding it just when planets had collided or comets descended were nil, and the amount of detectable infrared radiation was a bad fit for all of those possibilities.
Increasingly, astronomers were forced to consider the unthinkable—that the odd light curve of KIC 8462852 was due to some sort of alien megastructure, an intelligently designed and built structure or series of structures, such as a Dyson sphere under construction or, more likely, a Dyson swarm—thousands of objects absorbing energy from the star. The light curves seemed to suggest solid-edged, irregularly shaped structures with distinct boundaries rather than diffuse clouds of dust.
But the alien megastructure idea had to be the very last possibility to be considered. That was not because the astronomers didn’t want to think about aliens, but because the alien hypothesis was not falsifiable by scientific testing … and so it could not be considered until every other possibility had been tested and ruled out.
And eventually, a natural explanation was found. Fast-spinning stars could suffer an effect called gravitational darkening while flattening from a sphere into an oblate spheroid; several large planets transiting across different parts of the star’s surface, plus an accretion disk of dust, could cause greater or lesser dips in the light curve.
There were problems with that theory, though. The star did spin quickly—at the equator it rotated once in 21 hours and a few minutes as opposed to 25 days for Sol—but not fast enough to cause severe distortion of the sphere. And, again, the star just wasn’t young enough to have an orbiting cloud or accretion disk of dust.
But by that time, the twenty-first century had been in free fall toward utter chaos. Stunning and widespread political corruption, quickly rising sea levels, economic collapse, global war with Islam, the First Sino-Western War, and the ravages of the Blood Death … it was a wonder, frankly, that Humankind had survived. The hanging of the first space elevator, in the twenty-second century, had helped reverse the collapse, bringing in the raw materials, cheap energy, and improved technologies that ultimately transformed the planet.
But as Humankind began to establish a firm foothold in the solar system, the excitement over KIC 8462852 was largely forgotten. It became an interesting anomaly, quickly explained and as quickly filed away and ignored.
“Okay,” Koenig said after several minutes reviewing the material. “An interesting observation, but it says here they explained it. Why are the Agletsch interested in the thing? Or, maybe I should say … why do they want us to be interested?”
“They did not discuss that,” Konstantin replied. “But they seem to believe that our explanation was wrong. That Tabby’s Star is in fact the location of an advanced alien civilization.”
“But not an ally of the Sh’daar, I take it.”
“Correct.”
Humankind now understood that the Sh’daar were interlopers from the remote past, from T-0.876gy … a term usually abbreviated as “Tee-sub-minus,” or, in other words, from 876 million years in the past. They appeared to have recruited a number of alien civilizations in Tprime (meaning time now, the twenty-fifth century): the Turusch, the H’rulka, the Nungiirtok, the Slan, and quite a few others. That alliance, called the Sh’daar Collective, had been deployed against Humankind in an effort to force them to give up tech-singularity-inducing technologies. The Collective apparently extended into the future as well; the Glothr, from a rogue planet millions of years in the future, might well have been working with the Sh’daar, though the nature of that relationship was still uncertain.
The only reason Humankind had survived against that alliance as long as it had was the fact that the different members of the Sh’daar Collective had as much trouble communicating with one another as they did with humans. Organizing a joint military campaign across millions of years and with dozens of space-faring species with wildly diverse means of communicating turned out to be damned near impossible.
“Huh,” Koenig said, thoughtful. “If the Tabby’s Star aliens haven’t been pressured by the Sh’daar, they might turn out to be useful allies for us.”
“Exactly. Assuming, of course, that they care to involve themselves with humans.”
“What … they might not because we’re so primitive? Or would they be put off by our body odor?”
“Whatever terrestrial astronomers observed at Tabby’s Star in the year 2015,” Konstantin reminded Koenig, “would have happened 1480 years earlier … in the year 535 C.E., to be precise. If they were actually building a Dyson sphere when Europe’s Dark Ages were just getting started, where are they, and what are they building now? Such beings might seem like gods compared to humans.”
“The Stargods …” It was an old idea, one suggesting a source for unexplained technological artifacts like the TRGAs scattered across the galaxy … or the Black Rosette at the heart of Omega Centauri. Laurie Taggart had been a passionate devotee of that idea, a member of the Ancient Alien Creationist Church.
But it was also an idea that explained nothing.
“What people enamored of the Stargods tend to forget,” Konstantin said, “is that such beings very likely have absolutely nothing in common with us. Would you stop to communicate with an anthill?”
“I don’t know,” Koenig replied with a virtual shrug. “It depends on whether I could understand what the little buggers were saying. And there are entomologists who would be interested in finding a common language, if there was one.”
“It is possible to push such metaphors too far, Mr. President. The point is that the Tabby’s Star aliens may have nothing whatsoever in common with humans, and no wish to communicate with them … or to help them against the Sh’daar.”
“I could also imagine them having reached their own technological singularity,” Koenig said. “They might have built the thing, whatever it is … and then left. They’re not around any longer.”
“True. Still, the fact that the Agletsch have suggested that a human ship explore Tabby’s Star outweighs,