If you feel like flat Earth theory has gotten unaccountably popular recently, you’re right. According to Google Trends, search interest in the flat Earth conspiracy theory has already had several distinct peaks in the last year. (“The last year” was 2017, not 1519, just to be clear.) It’s funny, weird, and while it’s certainly not at the top of our list of problems as a society, it’s not entirely innocent either.

Interest surged in February and March, then again in May, then again in August and September. These jumps are mostly tied to a couple of strange outbursts by celebrities, notably 2010’s favorite cheeseball rapper and Gossip Girl backing vocalist B.o.B. and Boston Celtics point guard Kyrie Irving. But interest in the topic has been climbing steadily since late 2014, shortly after a faction of Daniel Shenton’s “Flat Earth Society” broke away to create its own website and forum. The FAQ page for Flat Earth Society is the third Google search result for “flat Earth,” and encourages people to distrust science completely, as the best way to experience reality is “by relying on one’s own senses to discern the true nature of the world around us.”

News outlets contribute, too, because explainers about the flat Earth conspiracy do incredible traffic. They’re capitalizing on a basic human interest in mysteries and the strange behavior of others, and they’re also wading into an online environment where it’s impossible to differentiate a joke from a deeply held belief. That’s a recipe for one viral hit, then another. It’s been a huge, thrilling year for flat Earth truthers.

The Flat Earth Society’s site — which posits that the idea of a round Earth is somehow related to the faking of the Moon landing — is remarkably well-designed and professional-looking, eliminating some of the old hallmarks of disinformation on the internet. The ease of creating a website as clean as this one is a problem that has been well-documented by information scientists. As recently as five years ago, high schools were teaching that you could identify a disreputable source by its cheap-looking site, bad design, and messy URL. That no longer holds.

Digital newsrooms churn out coverage of flat Earth truthers using tools that make it easy to find stories bubbling up from the depths of Reddit. Here’s how it works: conspiracy theories get people fired up enough to comment promiscuously, bringing them to the front of Reddit where journalists see them, says The Verge’s editorial director Helen Havlak. When a reporter writes an explainer of a new oddball conspiracy theory, the sharing and hate commenting that drove the theory to the top of Reddit reoccurs on Facebook. And, if the post is coming from a generally reputable outlet or involves a celebrity (e.g., B.o.B. or Kyrie Irving) or a major news event (e.g., a presidential election), it can also get a boost into the Top Stories slot on Google News. “Newsrooms watch each other’s highest-performing stories,” Havlak says. It’s common practice to use a tool that lets newsrooms make lists of their competitors and monitor the popularity of their posts (on services like CrowdTangle, for example) to see what’s doing well for other outlets, and what might be a sure traffic bet if they could find a fresh angle or a reason to weigh in. “People see all the traffic to be had, and look for the next thing trickling up from Reddit,” she says. “Cycle repeats.”

“People see all the traffic to be had, and look for the next thing trickling up from Reddit.”

Flat Earthers have received extensive coverage from platforms as diverse and prestigious as Vice, The Atlantic, Sports Illustrated, The Guardian, and Mic. Obviously none of these outlets indulge flat Earth theory as plausible, or even remotely rational — but they do contribute to its ongoing popularity by feeding the appetite for these stories.

Using CrowdTangle, we can comb through months of posts on the Facebook pages for major science and news outlets. The interface is simple, and shows how many likes, comments, and shares each post gets above or below that page’s usual number. Unsurprisingly, flat Earth conspiracy articles far outperform the average for these pages: LiveScience’s “Is Earth Flat? A Guide to the Ultimate Conspiracy Theory” received about 11 times the Facebook engagement (likes, comments, and shares) as the average LiveScience post. CNET’s “This is what flat-earthers on social media really believe” was about 16 times as popular as the average post on that page. Last year, Mic’s fledgling tech and science vertical The Future is Now posted the same flat Earther explainer, titled “There is a Massive Conspiracy to Hide the Fact That the Earth is Flat,” twice in the same month, for a total of over 1,000 shares, at a time when that page was averaging closer to 30 shares per post. Though I used these Facebook statistics as an approximation for how well flat Earth posts did in comparison to other posts on various news sites, Havlak says the majority of traffic on posts The Verge has published about other conspiracy theories — including two posts that I wrote, about the One Direction Babygate theory and the “Ted Cruz is the Zodiac Killer” theory — came from Google. The Top Stories box is crucial, and Google is still most people’s first go-to when their curiosity is piqued.

An admin of the Flat Earth Society site also wrote a personal thank you note to Yahoo! News in January, writing, “Every article like this spreads our message to more unaware minds.”

Not everyone who’s reading or sharing these posts can possibly be believers in flat Earth. I asked Joseph Uscinski, a political science professor at the University of Miami who recently co-authored a history of American conspiracy theories, why people who don’t believe in the flat Earth theory would waste their time reading about it. Reading about a conspiracy theory is “not unlike [watching] an M. Night Shyamalan movie in the theater,” he says. These theories “posit alternative realities full of schemes and skullduggery… Did secret agents plant explosives in the Twin Towers to fake a terror attack? Did the Mafia undertake a hit against President Kennedy? Do interdimensional lizards secretly interbreed with humans while running the planet? Even if one is not convinced, there is plenty of entertainment there.”

Also, the feeling of reading about a conspiracy theory is kind of like the sensation of watching Mr. Robot, says Mark Fenster, an expert in government transparency at the University of Florida law school and author of Conspiracy Theories: Secrets and Power in American Culture. That show, and the thrillers and mystery novels that preceded it, play with the idea that “you have a certain set of understandings and beliefs that you are taught and that you believe are true, but in fact, if you actually look closely at them and understand the truth of the matter, those beliefs are proven to be false. That is — in a fictional universe — extremely enticing and extremely exciting. It can be a source of fun.”

As for people who actually believe in flat Earth theory, Fenster says, you can’t really change their minds with photographic evidence or mathematical proof of a round Earth. To believe in a theory like this one, you have to go way, way past the normal threshold for questioning expertise and “hierarchies of intellectual knowledge.” It’s fun for us to have our perceptions pulled apart in fictional thrillers and mysteries, but we consider a narrative satisfying only when it also offers a way to put things back together. People who believe in flat Earth have already decided that the world around them can’t possibly be what it seems, and so a conspiracy theory becomes “a nice way of efficiently explaining what would otherwise be a confounding world,” Fenster says.

“You can do these fun and games and never really be called on it.”

The flat Earth theory is spreading online, and it’s hard to tell where the joke begins or ends. We can prove that hundreds of thousands of people are aware of an obscure belief that they weren’t before, but we can’t prove whether this has actually converted a substantial number of them to the cause. The United States has been “crazy with conspiracy theories” since before the Revolutionary War, Fenster says; the percentage of Americans who believe in some conspiracy or another around the JFK assassination has hovered between 60 and 80 percent for the last 50 years. But, “there are fun and games with conspiracy theorizing,” he says. “We don’t really believe them, but we know a lot about them, but maybe we do believe them a little, but we’re actually just sort of joking and playing. People are doing that winking thing on Reddit. You can do these fun and games and never really be called on it.”

It’s true that the theory is so absurd as to be kind of funny, and it’s fair to say that people who believe in it aren’t directly endangering anyone’s lives. That’s one explanation as to why people might click on a flat Earth thread even though they would never share an anti-vaccine meme or a joke about AIDS being a hoax. Still, there’s something unnerving about cultivating an online environment in which none of our actions are sincere: a click is an ironic click; a share is a hate-share; a comment is tongue-in-cheek, play-acting, or just “lol.”

There are hundreds of memes making fun of flat Earth by feigning a devout belief in it, and a lot of them are pretty entertaining. Know Your Meme even counts “Flat Earth” as a genre of meme, and provides a helpful timeline of its spread, mainly across Reddit. Know Your Meme editor Matt Schimkowitz told me there’s a rhythm to the growth of theories like flat Earth. They’ll show up on 4chan and Reddit and believers will start out as the subject of ridicule. Their belief will become a joke that’s repeated faux-sincerely and increasingly emphatically by people who consider everything they say to be “ironic.” That’s where memes come in, and in this case they represent a style of mockery that looks an awful lot like agreement. “From there it can kind of spiral,” he says. “It can attract people who are looking to believe in these kinds of things, looking for things to confirm what they believe — like the government’s out to get them, scientists are lying to us, that sort of deal. What starts as an ironic thing eventually reaches people who are willing to go along with it. From there you have sort of full-blown conspiracy theories. It reaches a new level.”

“You can turn people into something different just through irony,” he says. He noticed this trend in the wake of the 2016 election and in countless excavations of the online dens of the alt-right, where people would start out saying they were just joking about racism or anti-Semitism. But engaging with that type of humor for long enough could eventually radicalize them. He says he sees the same process happen with conspiracy theories. If you can get people to ironically question systems like NASA and the federal government and the scientific process in general, you can sometimes get them to question those things for real.

Schimkowitz understands that flat Earth trutherism isn’t as immediately dangerous as climate change denialism or the anti-vaccine backlash, but that doesn’t mean it’s totally harmless. “I think it is important to maintain a level of concern about [conspiracy theorists],” he says. “They do things that harm society as a whole, like negate or dilute scientific reason. That’s something that’s having profound impact on everyone. Looking at climate change denialism, that comes from just doubting the idea of expertise as a whole. Conspiracy theorists attack expertise.”

Though Schimkowitz is speaking only to his experience with conspiracy theories on 4chan and Reddit, sociologist Ted Goertzel, who specializes in researching scientific conspiracy theories at Rutgers, told me almost the exact same thing. The basic goal of a conspiracy theorist, he says, isn’t usually to prove that one specific theory is true or false, but “to prove that nothing is provable, that all assertions are arbitrary.” He, too, sees an obvious case study in the recent election cycle, arguing that this is the type of thinking that leads people to believe that absolutely everything is “arbitrary and manipulative,” and that anything they don’t agree with is “fake news.”

“Conspiracy theorists attack expertise.”

Both Goertzel and Schimkowitz brought up the Pizzagate controversy of last year, in which a Reddit conspiracy theory that started as a joke resulted in a man showing up at a Washington, DC pizza shop with a gun, intending to release prisoners being held there by Hillary Clinton. Real people’s lives were put in danger by an idea delivered in a context that treats sincere arguments and jokes exactly the same — like faceless, morally neutral, almost random series of words for which no one is accountable. “That is one of the great problems of the internet right now,” Schimkowitz says. “It’s hard to tell the difference between a joke and sincerity. In terms of judging where the joke begins and ends, it’s almost impossible to tell at this point.”

In September, Kyrie Irving told Boston radio host Rich Shertenlieb he was just kidding about being a flat Earther. He just wanted to have an “open conversation” and prove a point: “[If] I believe that the world is flat, and you believe that the world is round, does that knock my intellectual capacity, or the fact that I can think different things than you can?”

It’s hard to call him on it. He’s just joking.