Fighting flat-Earth theory

by RACHEL BRAZIL

IMAGE/Claus Lunau/Science Photo Library

In 2017 the US rapper B.o.B (real name Bobby Ray Simmons Jr) started a crowd-funding campaign to launch a satellite. The rapper, a vocal proponent of “flat-Earth theory”, wanted to seek evidence that our planet is a disc, not a globe. His aim was to raise $200,000 (later upped to $1m) on the GoFundMe website, with the aim of sending one or more craft into space to help him “find the curve” – the term that “flat-Earthers” use to describe the edge of our supposed disc-shaped planet.

The rapper’s quest may seem like a joke or publicity stunt. Indeed, there’s currently no evidence that B.o.B raised much money or got anywhere near his goal. However, in the last few years there has been an alarming rise in the number of people who, like B.o.B, believe in flat-Earth theories. There’s now an annual flat-Earth conference in the US – the most recent of which was attended by more than 600 people – while YouTube is full of videos purporting to provide evidence that the Earth is flat.

Physicists may mock the notion of a flat Earth, but the idea is gaining traction, particularly among people susceptible to other conspiracy theories. “They actually really do believe it,” says Lee McIntyre, a philosopher from Boston University and an expert in the phenomenon of science denial, whose books include Respecting Truth: Wilful Ignorance in the Internet Age (Routledge, 2015). McIntyre knows first-hand how sincerely flat-Earthers hold their views: he attended the 2018 Flat Earth International Conference in Denver, Colorado.

Asheley Landrum, a psychologist from Texas Tech University who was also at the Denver meeting, agrees that flat-Earthers are genuine, and not goofing around. “If they were [trolling], they are very good actors,” she says. “We talked to more than 90 members of the flat-Earth community and they’re all very sincere in their beliefs”. Lectures at the Denver event included “Talking to your family and friends about flat Earth”, “NASA and other space lies” and “14+ ways the Bible says flat Earth”.

Flat-Earth ideas are based on basic scientific misunderstandings that can be easily refuted. For most people, even those who have no physics background, the evidence for a spherical Earth is obvious. So we need to ask ourselves why these ideas still persist in the 21st century and, perhaps more importantly for the physics community: how exactly should we respond?

A circular history

The idea that the Earth is a sphere was all but settled by ancient Greek philosophers such as Aristotle (384–322 BC), who obtained empirical evidence after travelling to Egypt and seeing new constellations of stars. Eratosthenes, in the third century BC, became the first person to calculate the circumference of the Earth. Islamic scholars made further advanced measurements from about the 9th century AD onwards, while European navigators circled the Earth in the 16th century. Images from space were final proof, if any were needed.

Today’s flat-Earth believers are not, though, the first to doubt what seems unquestionable. The notion of a flat Earth initially resurfaced in the 1800s as a backlash to scientific progress, especially among those who wished to return to biblical literalism. Perhaps the most famous proponent was the British writer Samuel Rowbotham (1816–1884). He proposed the Earth is a flat immovable disc, centred at the North Pole, with Antarctica replaced by an ice wall at the disc’s outer boundary.

The International Flat Earth Research Society, which was set up in 1956 by Samuel Shenton, a signwriter living in Dover, UK, was regarded by many people as merely a symbol of British eccentricity – amusing and of little consequence. But in the early 2000s, with the Internet now a well-established vehicle for off-beat views, the idea began to bubble up again, mostly in the US. Discussions sprouted in online forums, the Flat Earth Society was relaunched in October 2009 and the annual flat-Earth conference began in earnest.

1 Why distant skyscrapers are visible despite the curvature of the Earth

Chicago skyline IMAGE/© Sam Cornwell, 2008

This photo was taken from Mount Baldy in Indiana Dunes National Park on the south-east coast of Lake Michigan, roughly 60?km across the water from the city of Chicago, which lies on the opposite bank. At that distance, Chicago’s skyline should not be visible as the curvature of the Earth takes it beyond the horizon. The fact that the buildings are visible is in fact simply a mirage. Mirages are usually created when a cold, dense layer of air sits above a layer of warmer, less dense air, for example when the Sun beats down on a black road on a hot summer’s day. The warm ground heats the bottom few centimetres of air, refracting sunlight up to your eyes to create an “inferior mirage”. But if a layer of warm air sits above your line of sight, with a cool layer beneath, you get a “superior mirage”. Light bends down towards the denser air, but because our eyes assume the light has travelled in a straight line, the object appears higher than it is. The effect also explains why a far-off ship can be seen even though it might have dipped below the horizon. It can even make distant boats appear to float in the air.

IMAGE/CC-BY-SA / Ludovica Lorenzelli, DensityDesign Research Lab

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