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The story behind 'alien megastructures' scientists may have found (but probably didn't)

A story that went viral this week reports that astronomers finally found E.T., but those aren't the facts. CNET's Eric Mack talks with the astronomers involved about what is still a very interesting star.

The star system might look something like this, but weirder.Photo by University of Rochester/Ron Miller

This is a tricky story to write. The mysterious scientific observations it deals with could wind up being nothing, or they could amount to some new, interesting astrophysical phenomenon that gets its own little section in a planetary science textbook someday. But there's also the tiniest chance that some perplexing light curves from a distant star over 1,400 light-years from Earth could be the beginning of the biggest discovery since not just the birth of modern science, but the birth of well, the human race.

Yes, you guessed it, I'm talking about the possibility that we may have the first scientific evidence of intelligent life beyond our own solar system. The story's been all over social media, TV and everywhere else this week since originally being reported by The Atlantic. You might have heard that astronomers think they've spotted giant solar collectors, Dyson spheres or other megastructures straight out of sci-fi built by an advanced alien civilization around a far-off star unremarkably named KIC 8462852.

The only problem is it probably isn't any of those. But even if we haven't spotted distant aliens, whatever it is we have spotted is undeniably odd at the very least.

Basically, the star's light curve seems to show some strange stuff passing in front of the star, at irregular intervals and sometimes even appearing to shift shape or orientation along the way. This is very different from the relatively predictable orbits we see objects make around our own sun and most other stars that Kepler has observed.

As soon as I read the original Atlantic piece, I reached out to the Yale postdoctoral researcher who has studied KIC 8462852 for the past four years and to two leading scientists with an interest in the search for extraterrestrial intelligence (SETI) who now hope to check for signs of life around the star beginning as soon as February. All three stressed that aliens are probably not the the source of the mysterious light curves observed by the Kepler Space Telescope from star KIC 8462852.

In fact, Tabetha Boyajian, the Yale postdoc who outlined years of research on the star and submitted it for publication in Monthly Notices of the Royal Astronomical Society in September, didn't even mention the possibility of alien structures in the paper (PDF). She thinks her leading hypothesis that Kepler is perhaps seeing a swarm of colliding comets around the star is compelling enough, without having to pull the E.T. card.

"[The alien hypothesis] was discussed and we decided to keep the paper that I wrote [to] completely astrophysical, natural phenomena," she told me.

But if you're a scientist and the search for extraterrestrial intelligence happens to be your particular field of study, which it's not for Boyajian, then KIC 8462852 is the biggest thing to come along in quite some time.

"It is the most interesting singular object from a SETI perspective that we know about today," said Andrew Siemion, director of the University of California's Berkeley SETI Research Center.

Boyajian is now helping draft a proposal for further research with Siemion, who just a few weeks ago mentioned Dyson megastructures in his testimony to Congress during a hearing on astrobiology research, and Penn State professor Jason Wright, an astronomer and noted authority on SETI when it comes to the search for megastructures.

The proposal requests observation time on powerful radio telescopes like the National Radio Astronomy Observatory in Green Bank, West Virginia, to check for signs of life coming from the vicinity of KIC 8462852.

The National Radio Astronomy Observatory in Green Bank, W.V.Photo by NRAO

But getting to this point wasn't as simple as looking at some data and then whispering "Is that aliens?" into the exponential megaphone that is the Internet.

KIC 8462852 is just one of more than 100,000 stars that Kepler has stared at for a few years from its perch in space. Light curve data from all those stars gets fed into algorithms that look for signs of slight, periodic dimming indicating planets might be passing in front of them. But because humans are often better than software at spotting patterns and anomalies, volunteer citizen scientists also eyeball Kepler data via an online platform called Planet Hunters.

"This object [KIC 8462852] was being discussed a whole lot by users on the [Planet Hunters] forum, which is how our attention got drawn to it years ago," said Boyajian, who is part of the science team for the site that helps vet results from volunteers. "We really didn't know what to do with it for quite a while...we'd never seen anything like it before."

A star for SETI researchers

After Boyajian and her colleagues determined that they weren't looking at the result of some sort of error or technical glitch, they tracked down more images and data on the star, as well as other expert opinions.

"Basically for years we were talking to, like, a hundred astronomers on the subject but we couldn't really nail down what was happening," Boyajian said.

One of those many astronomers was Wright, who coincidentally was working on an unrelated paper at the time on how Kepler could be used to search for alien megastructures.

"I thought it was really, really strange, but couldn't come up with anything (to explain the data)," Wright said. "I thought SETI astronomers should take an interest in it because it was sufficiently weird and sufficiently out there and sufficiently similar to what you might expect from an alien civilization that they should be interested."

So Wright, who says he has no experience doing radio SETI, reached out to Siemion, who recently told Congress the project he'd most like to see funded is a radio telescope on the far side of the moon.

"I hadn't looked at a lot of Kepler light curves, but I looked at the one that they showed me and I thought for sure that they had made some mistake," Siemion explained. "But because Jason and Tabetha are so prominent in their field I certainly paid attention to it, but even then, I still thought that there was some problem... or that they had missed something."

It wasn't until Jon Jenkins from the Kepler team, the guy who actually developed the algorithms used to process the raw pixel data from the spacecraft, vouched for the accuracy of the data that Siemion became convinced that he might be dealing with the most promising target yet for SETI research.

Still, Siemion remains prudently cautious.

'Hypothesis of last resort'

"The Dyson sphere explanation is...probably not the most likely explanation for what we're seeing. I think we have to assume a natural explanation is more likely. That said, it's not often in SETI that we have targets that come up from other areas of astrophysics that are such a compelling possibility to us."

Wright calls aliens a "hypothesis of last resort," because it's essentially impossible to falsify. But he says the current status quo in the SETI field is also reminiscent of the approach to the hunt for the first confirmed exoplanets decades ago. He says scientists looking to spot the first distant planets around another star set an extremely high bar because they feared embarrassing themselves and the entire field with claims that turned out to be false.

I asked Siemion if he had ever worked with another target as potentially promising for SETI work as this one. The best he could come up with are the mysterious "fast radio bursts" that have been detected over the past decade or so. When they were first detected, it seemed like these very powerful and distant bursts of energy might be a radio pulse from an advanced civilization, but since then other examples have been detected from other corners of the universe, suggesting the bursts might have a natural source rather than originating from a single intelligent source.

And that's usually how the science has gone up until this point with this sort of thing. We see something weird and new, be it "canals" on Mars, pulsars or fast radio bursts, and the mind veers toward the possibility of aliens, even if we think we ought to know better by now. Eventually, science investigates the new mystery further and often that process leads to a new discovery that broadens our understanding of how the universe works.

What it hasn't led to just yet is aliens, or their megastructures. But as Jason Wright told me, that doesn't mean we shouldn't check.

"You've just gotta rule everything out first. It's going to be an extremely long road to plow to confirm something."


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