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The Kepler space telescope found a star that randomly gets really dim, and some people are suggesting the star’s being blocked by a huge alien structure. It’s… probably not aliens, though.

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It’s starting to seem like every couple of months somebody decides to announce that... we’ve found aliens! Or at least... some evidence of them! Sometimes, it’s because scientists have found an unusually life-friendly exoplanet. Other times, like back in July, it was about the vaporizing ice on Comet 67P. This time, people are getting all worked up over a weird find from the Kepler space telescope -- and it could be aliens, I guess. But... probably not.

It could also be just a swarm of broken-up comets. Back in September, an international group of astronomers submitted a paper to the journal Monthly Notices of the Royal Astronomical Society, about a weird star called KIC 8462852. Bit of a mouthful, but there’s stuff about the star that’s even harder to understand: it randomly dims by about a fifth of its normal luminosity, for 5 to 80 days at a time.

Now, it’s worth noting that the paper hasn’t been through the peer review process yet; so far, it’s only been submitted to the journal. But, according to the team’s analysis, those fluctuations make this star super weird. Now there are all kinds of reasons why a star might look less bright sometimes. For example, an exoplanet passing in front of a star would block out some of its light -- which is actually the way that Kepler finds exoplanets. But they only cause stars to dim by at most one percent, and they do it predictably as they orbit. Dimming by 20%? That’s no planet.

It’s also definitely not a glitch. The astronomers checked for all the usual issues with their instruments and didn’t find any problems with the data. But here’s the thing: the researchers in the paper don’t say anything about aliens! That possibility comes from an interview with Jason Wright, an astronomer from Penn State University, who isn’t an author on the paper -- though he is thanked in the acknowledgments.

Wright plans to publish a separate paper about the star, and he says that the dimming could’ve been caused by what he’s calling a “swarm of megastructures.” The idea is that if super-advanced civilizations exist out there, they might decide to build huge structures that would capture more of their star’s energy. Those giant structures, the thinking goes, could block out a lot of a star’s light at unpredictable times.

But there are all kinds of problems with this idea -- for one thing, a civilization using that much energy would be putting out a huge amount of waste heat, which we’d detect in the infrared part of the spectrum. And one of the reasons that this star is so hard to explain is that it isn’t emitting extra infrared radiation. So, in their paper, the team explores a few different ideas that could more feasibly explain the dimming.

For example, there could have been lots of collisions in some kind of asteroid belt orbiting the star, which would release lots of dust. If that dust formed clumps, it could cause the dips in light that we see. Except that would also emit lots of infrared radiation, which again, we’re not seeing. The most likely explanation, according to the researchers, is that the star’s being blocked by a bunch of shattered comets.

Because: It turns out that the star has a companion, about 150 billion kilometers away. Now that’s around a thousand times as far as Earth is from the sun, but it’s more than 250 times closer than our nearest star. If that companion star passed close enough to the first star -- which we’ll just call KIC -- then it could have brought a lot of comets with it, which may have then broken up because of all of KIC’s heat and gravitation. Or the companion star could have interfered with the orbits of some of KIC’s own comets, knocking them close enough to it to break them apart.

So, how can we confirm that the star’s being blocked by comet debris, and not aliens? Well, the researchers have some ideas. We’ll have to observe the star for a while and see if there are any more unusual, irregular dips in how bright it looks. They also want to measure the orbit of that nearby companion star -- that way, they’ll have a better idea of when and how it could have destroyed all those comets, and see if the data match. Finally, it would help to monitor the star for the types of gas that a comet might release as it fell apart.

Meanwhile, the Search for Extraterrestrial Intelligence is also on the case, using the radio telescopes in San Francisco known as the Allen Telescope Array to look for signals that could have been made by intelligent life. But it’s much more likely that the dips are caused by comets, or something nobody’s thought of yet. Which are both fascinating possibilities-- we won’t know for sure until we do some more observing.

In the meantime, thanks for watching this episode of SciShow Space News, and thank you especially to all of our patrons on Patreon who make this show possible-- pay for all the people sitting around me. Say thanks guys. Thank you! Thanks! And if you want to hear all about aliens if we ever do spot some, you can go to and subscribe.