'Behind the Curve' Ending: Flat Earthers Disprove Themselves With Own Experiments in Netflix Documentary

There are many head-shaking moments in Behind the Curve—a 2018 documentary, now on Netflix, that follows luminaries of the Flat Earth movement, particularly YouTuber Mark Sargent. The most surprising may be the rigor with which believers in a Flat Earth disprove themselves. Twice in Behind the Curve, experiments show the opposite of what Flat Earth advocates hope to demonstrate, with one such experiment, involving a flashlight, serving as the documentary's ending.

Behind the Curve, now on Netflix

"Science is having a problem combatting what we are doing," Mark Sargent says early in Behind the Curve, citing the fact that he can see Seattle skyscrapers from his mother's home on Whidbey Island, when he presumes they should be hidden behind the Earth's curvature. "Neil Degrasse Tyson—I hate saying his name, we call him He-Who-Shall-Not-Be-Named—says that, 'It's a growing anti-intellectual movement that borders on the end of civilization and democracy as we know it.'"

Cut to Tyson's 2016 appearance on Comedy Central's The Nightly Show with Larry Wilmore : "The Earth isn't fucking flat."

"The reason why we're winning against science is that science just throws math at us," Sargent says in Behind the Curve. Sargent and other proponents of a Flat Earth believe that our planet is covered by a gigantic dome, with the sun and moon rotating in circles above our heads. Antarctica isn't a unified continent, but a giant ice wall—just like in Game of Thrones, Sargent says—that surrounds the continents of Earth. Later, the documentary checks in on people with even more fantastical beliefs, including theorizing that additional, undiscovered continents are out there, beyond the wall.

Mark Sargent shows a miniature model of the Flat Earth in documentary "Behind the Curve," now streaming on Netflix. Delta-V Productions

But more than a parade of eccentrics, Behind the Curve delves into the mindset that propagates dogmatic, unscientific propositions like Flat Earth, including what happens when their preconceived conclusions are challenged by their own experimental evidence.

One of the more jaw-dropping segments of the documentary comes when Bob Knodel, one of the hosts on a popular Flat Earth YouTube channel, walks viewers through an experiment involving a laser gyroscope. As the Earth rotates, the gyroscope appears to lean off-axis, staying in its original position as the Earth's curvature changes in relation. "What we found is, is when we turned on that gyroscope we found that we were picking up a drift. A 15 degree per hour drift," Knodel says, acknowledging that the gyroscope's behavior confirmed to exactly what you'd expect from a gyroscope on a rotating globe.

"Now, obviously we were taken aback by that. 'Wow, that's kind of a problem,'" Knodel says. "We obviously were not willing to accept that, and so we started looking for ways to disprove it was actually registering the motion of the Earth."

Despite further experimental refinements, Knodel's gyroscope consistently behaves as if the Earth is round. Yet Knodel's beliefs seem unchanged when discussing the experiment at a Flat Earth meetup in Denver. "We don't want to blow this, you know? When you've got $20,000 in this freaking gyro. If we dumped what we found right now, it would be bad. It would be bad. What I just told you was confidential," Knodel says to another Flat Earther in attendance.

But it's Knodel's YouTube co-host, Jeran Campanella, who provides the most dramatic example of a Flat Earther experiment disproving movement dogma.

Behind the Curve Ending: The Light Experiment

"Deep down inside, I think everybody knows that it's flat," Campanella says while speaking at the 2017 Flat Earth International Conference in Raleigh, North Carolina, near the ending of Behind the Curve.

Campanella devises an experiment involving three posts of the same height and a high-powered laser. The idea is to set up three measuring posts over a nearly 4 mile length of equal elevation. Once the laser is activated at the first post, its height can be measured at the other two. If the laser is at eight feet on the first post, then five feet at the second, then it indicates the measuring posts are set upon the Earth's curvature.

Campanella's proposed laser experiment, as seen in Flat Earth documentary "Behind the Curve," now streaming on Netflix. Delta-V Productions

In his first attempt, Campanella's laser light spread out too much over the distance, making an accurate measurement impossible. But at the very end of Behind the Curve, Campanella comes up with a similar experiment, this time involving a light instead of a laser. With two holes cut into styrofoam sheets at the same height, Campanella hopes to demonstrate that a light shone through the first hole will appear on a camera behind the second hole, indicating that a light, set at the same height as the holes, travelled straight across the surface of the Flat Earth. But if the light needs to be raised to a different height than the holes, it would indicate a curvature, invalidating the Flat Earth.

Campanella's proposed light experiment, which seems to invalidate the Flat Earth theory at the ending of documentary "Behind the Curve," now streaming on Netflix. Delta-V Productions

Campanella watches when the light is activated at the same height as the holes, but the light can't be seen on the camera screen. "Lift up your light, way above your head," Campanella says. With the compensation made for the curvature of the Earth, the light immediately appears on the camera. "Interesting," Campanella says. "That's interesting." The documentary ends.

While a satisfying ending for anyone hoping to see the Flat Earth movement hoisted by its own petard, Behind the Curve offers several reasons why empirical evidence is rarely capable of turning people away from their conspiracy theory beliefs.

"Say you lose faith in this thing. What then happens to my personal relationships? And what's the benefit for me doing that? Will the mainstream people welcome me back? No, they couldn't care less. But, have I now lost all of my friends in this community? Yes. So, suddenly, you're doubly isolated," psychologist Dr. Per Espen Stoknes says in the documentary. "It becomes a question of identity. Who am I in this world? And I can define myself through this struggle."

"If I tried to go…" Sargent says in the documentary, contemplating the scenario described by Dr. Stoknes. "They would come and say, 'Don't, don't do it.' So I couldn't, even if I wanted to."

"Then, all of a sudden, you get people that, maybe, work in our government, that don't believe what 97 percent of what all climate experts say," former NASA astronaut Commander Scott Kelly says in Behind the Curve, highlighting a too-real danger of anti-science beliefs.

"Mark, my grandkids are 12, 10 and eight years old and are all third-generation Flat Earthers," Sargent reads from a fan letter at the International Flat Earth Conference. "When their science teacher was telling the kids the Earth spins at a thousand miles an hour and goes around the sun, the class erupted, with about a third of the class saying, 'No, it doesn't.'"

The audience cheers. "Long live Flat Earth," Sargent finishes.