Friends don’t let friends believe in flat Earth theory.  Let’s spread the work, and bust some more “proofs”!  Click here for part 1 and part 2.

PART III. ATTEMPTS TO PROVE THE EARTH IS FLAT BRING ONLY PAIN

    11) The Bedford Level Experiment. In 1870, a flat Earther bet that he could prove the Earth was flat. He lost and ended up in jail. 

This is an interesting story. As early as 1838, and Englishman by the very English name of Samuel Birley Robotham* had been performing experiments on the Bedford river in which he lined up several markers of uniform height over the water and used a surveyor’s telescope to “prove” that there was no curvature to the earth. No one paid much attention to Robotham, however, probably because he was wrong. He had forgotten to take into account the refraction of light by the atmosphere (explained in nauseating detail here), which bends light close to the surface of the earth. Sailors had known to correct their telescope sights for light refraction for a hundred years by this time, so Robotham was a bit out of the loop.

Then, in 1870, a guy named John Hampden bet the naturalist Alfred Russel Wallace that he could repeat Robotham’s experiment and prove the Earth was flat. Wallace, however, knew about light refraction, corrected for it, and proved Hampden wrong. Hampden did not accept defeat gracefully – he harassed and defamed Wallace for years, and was eventually jailed for libel and threatening to kill the naturalist.

12) The observational proof.  But I can SEE that the ground is level!

Really? Come on. We have pretty much covered this already when discussing perspective (part 1, proof 1) and the level on the plane dude (part 2, proof 1). The curvature of the earth is too gradual to detect without expensive experiments (like the correctly performed Bedford level experiment!) or a bunch of math.

Here’s an experiment I’d like to see a flat Earther perform. First, strap on some SCUBA gear and a wet suit and dive down to the bottom of San Francisco Bay. Bring a long tape measure and measure the distance between the two vertical supports for the bridge. Be sure to write it down. Now, put on your climbing gear and climb one of the two support towers with a super-accurate, really expensive laser range finder (sorry, you can’t use the laser range finder under water too). Assuming that the bridge supports are still level after a few earthquakes, the top of the support towers will be 2 inches further apart than the bottom – because of the curvature of the earth.

13) The Bishop Experiment.  Some dude named Tom Bishop used a telescope to look across Monterey Bay and see people on a Santa Cruz beach at a distance that would be impossible on a round Earth.

Tom’s numbers were wrong – he used an incorrect distance between the two points. He also forgot to take into account refraction, just like our old English friends Robotham and Hampden.

Here’s another easy but expensive way to prove the earth is a sphere: Travel to Dubai, UAE. There you will find the Burj Khalifa, currently the tallest building in the world. Besides being very tall, the Burj Khalifa also has glass elevators which face west and are pretty fast (there are a lot of floors to cover, after all), and this is critical. You want to take the elevator up, but you’ll need to time your trip just right.  Find yourself one of the lower floors with a clear view to the horizon and watch the sun set. Just as the last piece of the sun is slipping below the horizon, jump on the elevator and hit the button for the top floor. You’ll notice something amazing – as the elevator goes up, the sun will appear to reverse it’s motion and rise back up again! When you get to the top and stop, the sun will resume setting for good. This happens because you have changed your perspective and looked “over” the horizon – something that would be impossible on a flat Earth.

Don’t have the time and money to fly to Dubai just to prove your flat Earther friends wrong? That’s ok, someone took a video of it.

14) Airy’s Failure.  This experiment proved that the stars move around a stationary Earth!

No it didn’t. Let’s start from the beginning: Sir George Biddell Airy was a mathematician and astronomer. He made numerous contributions to planetary orbit theory and during his time serving as the Astronomer Royal, established the Greenwich Meridian – accepted at the time as the 0 degree longitude line on the surface of the Earth. In 1871, Airy performed an experiment in which he tried to calculate the drag produced by something called “aether” on light. You probably haven’t heard of aether before, and for good reason: it doesn’t exist. However, in the 19th century, it was believed that light needed a substrate to move through, and this subtrate was called aether. Airy’s experiment, which involved filling a telescope with water to slow down the light and measuring the angle of the light entering the tube, failed to show the expected drag on the movement of light, thereby failing to support the prevailing aether theory.

These data don’t say anything about the shape of the Earth one way or the other, but flat Earther’s think this proves that the Earth is stationary. Why? Now it get’s complicated. Airy was trying to understand a phenomenon known at the time as the aberration of light. Discovered in the 1600’s this aberration is basically the apparent motion of stars from their true positions. In Airy’s time, it was unclear what exactly was causing this motion, but the prevailing theory was that the aether was causing “drag” in the path of light form distant stars. When Airy’s experiment failed to find evidence for this effect, flat Earthers seized upon the data because one other potential explanation for the negative finding was that the earth wasn’t actually moving at all – it was fixed and only the stars moved. Airy himself did not believe this – he was a brilliant astronomer and mathematician after all – he was well aware that the Earth orbited the sun, but was still at a loss to explain the aberration of light. So what is really going on here?

It took the mind of Albert Einstein to figure this out. When he published his paper on special relativity in 1905 he unified all the current theories concerning the nature of the light aberration and disproved the existence of the aether once and for all. The details of relativity are too complicated to get into here, but it means that as observers on a moving planet observing a star which is also moving independently, identification of the motion of those stars would be impossible using the methods employed. Basically, a fixed universal reference system was impossible because time and space are not fixed – on this scale, they are dependent on gravity and observation bias.

15) The Michelson-Morley Experiment.  This one totally proved the Earth was stationary!

The other “famous” experiment that is often cited as proof that the Earth is stationary is the Michelson-Morley experiment. Several years after Airy failed to detect the aether, Albert A. Michelson and Edward W. Morley tried a different approach.  Instead of looking for a change in the angle of light in a telescope, Michelson and Morley used two calibrated perpendicular beams of light, and expected that they would be able to detect the “dragging” effect of the aether on one (the one going against the direction of the movement of the aether).  This experiment is also notable because they floated a rock in a bath of mercury, which sounds both really cool and incredibly dangerous.

Of course Michelson and Morley did not detect the expected shift.  As with the Airy experiment, some geocentrists (people who believe that the Earth is the fixed center of the universe with all planets and stars moving around it) interpreted this as meaning that the earth was not moving, but Einstein would show that this is not true – it’s just that the aether did not exist. It’s also worth noting that Michelson and Morley, well-respected physics and mathematics professors at Case Western Reserve University in Ohio, never interpreted their data as supporting the theory that the Earth did not move. Today, their experiment is held up as one of the earliest proofs of the relativity theory that Einstein would devise less then 20 years later.

In no way do either the Airy or the Michelson-Morley experiments provide any data concerning the shape of the Earth. Unlike the Bedford and Bishop experiments, these were serious, well-funded experiments by well-respected scientists that never doubted that the Earth was a sphere. Flat Earthers and geocentrists misunderstood the meaning of this work and seized on it as evidence that the Earth is the center of the universe, with the sun, planets and stars all orbiting around it. Of course, this is wrong – neither experiment is proof of a stationary Earth, only proof that relativity is a difficult scientific concept to understand. On the bright side, this could make for some fun responses to flat Earthers you might encounter who site either of these experiments as “proof” the Earth is flat:

“These experiments didn’t test the shape of the Earth, but they are proof of the theory of relativity, and since relativity is dependent on the theory of gravity, by extension, they proved that the Earth can’t be flat.”

or

“Wait, are you saying that you understand physics better than Albert Einstein?”

Click here for part 4 of UYBFS’s flat earth series. We promise this is the last one!

Got a flat Earth proof you’d like debunked? Add to the comments below.

* Possible origins of the name “Robotham”: 1) Samuel’s ancestors invested the first electric seat warmer. 2) One of his ancestors was a cyborg from the waist down. 3) He is closely related to a robotic Jason Statham.