Comets May Not Explain “Alien Megastructure” Star’s Strange Flickering after All

Feb 6, 2016

Photo credit: NASA/JPL-Caltech

By Shannon Hall

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.

The first signs of the star’s oddity came from NASA’s planet-hunting Kepler space telescope, which continually monitored the star (as well as 100,000 others) between 2009 and 2013. Astronomers, citizen scientists and computers could then search for regular dips in a star’s light — a sign that an exoplanet has passed in front of that star. The largest planets might block 1 percent of a star’s light, but Tabby’s star dropped by as much as 20 percent in brightness. That, in and of itself, would be weird. But the periodic dimmings didn’t occur at regular time intervals, either — they were sporadic. The signature couldn’t be caused by a planet, scientists said.

In September, a team led by Boyajian, a postdoctoral fellow at Yale University, tried to make sense of the unusual signal. First, the researchers looked into any angles that might mean there was something wrong with the data itself. They even checked in with Kepler mission scientists. But everything came out clean. “The data that we were observing with Kepler is, in fact, astrophysical,” Boyajian told Space.com.

Still, nothing about the observations indicated what might be causing the extreme interference. After considering many possible scenarios, Boyajian determined that dust from a large cloud of comets was the best explanation. But she admits that “it’s a bit of a stretch to have comets that are large enough to block that much of the light from the star.” With her paper published, she hoped that other astronomers would jump in with alternative solutions.

And they did. A month later, the star exploded into the public’s eye when Wright announced that an advanced extraterrestrial civilization could be responsible for the signal, assuming this civilization built a megastructure, like solar panels, around the star. And Boyajian thinks the theory is definitely worth a follow-up.


Continue reading by clicking the name of the source below.

4 comments on “Comets May Not Explain “Alien Megastructure” Star’s Strange Flickering after All

  • @OP – 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.

    Both are very speculative, but comets sound more likely.

    But scientists can’t be sure either way.

    This is the false dichotomy statement of someone who clearly has no idea what the possibilities are!

    We discussed this topic earlier here:-

    https://www.richarddawkins.net/2015/10/astronomers-may-have-found-giant-alien-megastructures-orbiting-star-near-the-milky-way/



    Report abuse

  • 2
    NearlyNakedApe says:

    @OP- A month later, the star exploded into the public’s eye when Wright announced that an advanced extraterrestrial civilization could be responsible for the signal, assuming this civilization built a megastructure, like solar panels, around the star.

    Yeah but that sounds a lot like wishful thinking. Plus, if those were giant solar panels, wouldn’t it make more sense to have them located in a way that they don’t move “sporadically” around their star but are rather placed in a fixed spot or in a stable orbit?

    I think the bottom line here is that a lot more observation and study are required before drawing any significant conclusions on this phenomenon.



    Report abuse

  • @NearlyNakedApe I think it would make more sense to build solar panels that are always on the same side of the sun as the planet they’re supposed to send the energy too — assuming that would be the case, they might as well live on the solar panels or something even more exotic.



    Report abuse

  • 4
    NearlyNakedApe says:

    @Mi-197378

    I think it would make more sense to build solar panels that are always on the same side of the sun as the planet they’re supposed to send the energy to

    Well that pretty much falls under the definition of a “fixed spot or a stable orbit” doesn’t it?



    Report abuse

Leave a Reply

View our comment policy.