Exposing PseudoAstronomy

September 20, 2008

Flat Earth Society – Introductory Post

Filed under: flat earth concept — Stuart Robbins @ 11:27 pm
Tags: , , , ,

Like my series on the Apollo Moon Hoax, the idea of a “Flat Earth” will be a topic that I will come back to in future blog entries, discussing some specific claims that are made.  For this first post on the topic, I am going to briefly outline the core concept and explain why it is flawed relative to what we know about the Earth, space, physics, and just plain ol’ common sense.

The main premise of the “Flat Earth” idea is that Earth is, well, flat.  People who believe this idea believe that our planet is a a few miles thick, and everything that is on it – continents, oceans, and ice caps – rest on this flat object (“flat” being a relatively thin object considering how large in diameter it would be).  In terms of basic geography, the North Pole is at the center of this disk, and Antarctica is actually a wall of ice that surrounds the outer rim, keeping the oceans from sloshing over.  I kid you not.  Earth is also the fixed center of the Universe, with everything “revolving around it in a plane level with the flat Earth.”

Flat Earth believers (for brevity, I will call them “flaterthers,” a term that I just made up with the emphasis on the second syllable and the first “a” being pronounced like the “u” in “fluff”, fla-TER-thers) point to five main arguments for their beliefs:

  1. Earth says still in space relative to … something.  In the 1800s, physicists thought that there was a universal “thing” called the “ether,” through which light was supposed to travel.  But an 1887 experiment now called the Michelson-Morley experiment disproved this concept by showing there was no preferred direction (even though they were trying to prove it) in perhaps the most famous “null result” in physics history.  However, the flaterther argument somehow uses this to say Earth does NOT move, there actually IS an ether, and somehow this supports their idea … though I honestly don’t understand how.
  2. The second argument that is made is that Earth can’t possibly orbit the Sun because (a) there’s no way for it to maintain its velocity over billions of years given that it’s traveling through an ether and therefore feels resistance, and (b) because when you orbit an object, there’s an acceleration, and any object “ahead” of the acceleration would get squashed and an object “behind” the acceleration would float away.
  3. Objects on a curved surface would fall off.  They’d slide “down” and when they reached the bottom, they’d fall off.  Hence, according to flaterthers, it’s not possible for people in the USA to be standing up and people in Australia to be upside down, relative to those in the USA … Australians would fall off.
  4. On a curved surface, there’s an inconsistent “down” direction, so if someone from the USA were to fly to Australia, they’d now be upside down!  (I’m not sure why this is a separate argument from #3, but they consider it one on their website).
  5. The only way to keep an ocean on the Earth is to keep it in the large bowl that is bound by the great sheets of ice that we normally think of as Antarctica.  And, the only way to keep the air on Earth is to protect it with a large dome.

Since I honestly don’t understand how #1 is used to justify the Earth being flat (they seem to equate that with Earth being the unmoving center of the Universe), I am not going to address it.  In other words, this is the “Non-Sequitur” logical fallacy – the argument that Earth may be stationary relative to some permeating substance doesn’t say anything about Earth being flat. 

#2 is a little difficult to address because it requires some basic physics concepts and math in order to understand.  First off, there are a few things they say that just aren’t true.  For example, they state that Earth orbits “the sun at a radius of around five-hundred million kilometers.”  This is not true.  Earth’s average distance from the Sun is 149,600,000 km, or about 93 million miles.  At the risk of sounding flippant … every school child knows this.  In addition, they say that “Earth is supposed to be a large, spherical shaped ball of rock flying through space at hundreds of thousands of miles per hour …”  Again, this is over-stated to make it sound impossibly big.  Earth’s average orbital velocity is 29.78 km/s, which is 107,200 km/hr, or about 66,470 mph.  Still pretty fast compared with our every-day lives, but not as big as they make it seem.

Their actual arguments (as opposed to bad math/numbers) are a little more difficult to address with this claim.  First off, no one has actually said Earth has maintained the exact same orbit and the exact same speed for billions of years – that is a Straw Man logical fallacy.  And Earth does travel through a medium – not the ether, but rather the solar wind.  The solar wind is made up of charged particles that are emitted from the Sun and stream outwards in all directions.  In addition, Earth sometimes encounters asteroids that hit it.  Every time something hits Earth, whether it be a giant asteroid or an elementary particle, the momentum from that object is added to Earth’s, and this can act to slow it down or speed it up.  Because asteroids are so much more massive than the solar wind, I’ll address the impact of asteroids:

Earth weighs 5.97*10^24 kg.  That’s a lot.  Let’s look at a dinosaur-killing, mass-extinction-causing asteroid impact – an asteroid that’s, say, 15 km in diameter – or around half the size of Manhattan.  The average velocity of an Earth-crossing asteroid is around 15-20 km/sec, and most asteroids are made of rock, with a density of 3-4 gm/cm^3.  That’s a total mass of 5*10^6 kg, or a difference of 18 orders of magnitude.  That’s about the difference between the mass of our entire galaxy vs. the mass of the planet Mars.  In other words, a dinosaur-killing asteroid event hitting Earth is like you, a person, running into a piece of dust.  Even if that dust is going faster than a speeding bullet, you are not going to feel it.  Similarly, even if Earth gets whacked by these things once every million years, it’s still not going to feel it.  So, unless they are claiming that the ether is more massive than these asteroids, this claim doesn’t hold water (so to speak).

As for the acceleration argument, this is just pretty much wrong.  Our reference frame – the reference frame of EVERYTHING on Earth – is Earth.  We move relative to our planet, our point of view is relative to our planet, and our velocity is relative to our planet.  Yes, Earth goes in a really big circle around the Sun, and so there is a very very very slight accelerating “force outward” away from the Sun, but it is so small that there is no way you can feel it, and you folks who go to Weight Watchers don’t need to try to plan to go and weigh yourself at midnight instead of noon to get a lighter weigh-in.

Argument #3 and 4 I’m going to lump together into the basic concept of a misunderstanding of gravity.  As I said in the paragraph above, Earth is our reference frame for everything in our daily lives, and that’s because it is so big and we are so close to it (relative to everything else) that we are completely dominated by its gravity.  In their third point, they argue that people would simply fall off of a round Earth once they get to the edge that “goes down.”  Their analogy is a beach ball, where if you simply pour sand on the top of a beach ball, it will follow the curve of the ball until it gets to the side and then just fall off.

The reason why this analogy doesn’t work is that the beach ball has effectively no gravity when compared with Earth.  Things “fall down” because gravity pulls it “down.”  “Down” is always towards the center of Earth (until you get beyond Earth’s gravitational pull).  Now, if the beach ball were out in empty space and it was the most massive object around, a grain of sand that was placed on it wouldn’t move … it wouldn’t “fall” anywhere because “down” would be towards the center of the beach ball, regardless of whether the sand was placed next to the part where you blow into the beach ball or placed on the opposite side.

This is why when an American goes to Australia, the American is not standing on their head when they get there.  Throughout the flight (or boat ride) over, “down” is constantly changing so that it always points towards the center of Earth.  In other words, yes, the plane effectively does turn upside down during the flight.  It just does it very very slowly and you don’t notice it because it’s just following the curve of the planet, with the bottom of the plane always facing the surface of Earth.  (And as a side note, if you go to Australia, stay longer in that country than it took you to fly there, speaking from personal experience.)

As for argument #5, I really just have to resort to the ad hominem response:  This is absurd.  The belief that Earth is covered by a dome to keep the air in and that the edge is a giant sheet of ice to keep the ocean in is a juvenile concept that requires massive conspiratorial claims to maintain (which they do) since it negates space telescopes, the Apollo lunar missions, and expeditions to Antarctica, among other things.  In addition, it flies in the face of simplicity, plausibility, and most people who are older than 5.

That’ll wrap up this post on introducing the Flat Earth concept (and flaterthers).  In future posts, I will address more specific problems with it, such as their explanation for seasons, sunsets, tides, their concept of gravity, and other tidbits.


  1. It never occurred to me before, but flat earthers must be people who never ever travel. I’ve been to the USA, and many other northern hemisphere countries, but live down under. I can attest that I haven’t “slid off” the earth in any place I’ve been.

    I researched flat earth a while back and remember some other details: the dome had little windows which allowed the clouds, sun, moon, etc to pass through. There was also a little door for angels or people who’d passed over, and a door to hell.

    From what I remember they had two ‘sources’ – the Bible, and Christopher Columbus.

    Flat earthers really just sound like gravity-deniers.

    Comment by flip — August 13, 2012 @ 9:15 am | Reply

  2. It is extremely doubtful that Columbus was a source for flat earthers. Contrary to popular belief, no educated person in the west of the roman empire at time of Columbus believed in a flat earth. In fact you have to go back to the 6th century Byzantine monk Cosmas Indicopleustes to find one.

    As the one of the doyens of Medieval History of Science, David C. Lindberg notes: “Cosmas was not particularly influential in Byzantium, but he is important for us because he has been commonly used to buttress the claim that all (or most) medieval people believed they lived on a flat earth. This claim…is totally false. Cosmas is, in fact, the only medieval European known to have defended a flat earth cosmology, whereas it is safe to assume that all educated Western Europeans (and almost one hundred percent of educated Byzantines), as well as sailors and travelers, believed in the earth’s sphericity.” (David C. Lindberg, “The Beginnings of Western Science, 600 B.C. to A.D. 1450”, p. 161).

    It is clear that the ancient biblical writers thought that the earth was a flat and there are some indications that it was perceived to be probably disc shaped.

    Comment by Ian Paul Wragg — December 20, 2012 @ 12:55 am | Reply

  3. Thank you for this informative blog. I will use this for a lab that I am doing for my Astronomy class at MSU, where I must develop counter arguments against the arguments of “The Flat Earth Society” (I can’t believe that this group actually exists). I of course give you full credit for helping me develop rebuttals for their arguments. Thank you, and have a great day!

    Comment by Jacob Vasquez Jr. — September 2, 2014 @ 6:11 pm | Reply

    • Glad it was useful.

      Comment by Stuart Robbins — September 2, 2014 @ 6:19 pm | Reply

  4. Both the Sumerian and ancient Egyptian civilisations knew the earth is NOT a globe but is actually flat. How arrogant is it to assume your magic spinning ball theory has any credit at all when you can’t even duplicate their architectural feats?Don’t you think with all their scientific advancements and knowledge about astronomy math architecture(involves mathematics too) they would have found out about a globe planet?Only when a gay greek philosopher came up with this incredibly unproven absurd idea of a spinning globe did the western world start going along with this fairy tale.

    Comment by Danny — July 15, 2016 @ 8:28 am | Reply

    • What a well thought out, rational, well-justified, and evidentiary argument!

      Comment by Stuart Robbins — July 15, 2016 @ 9:06 am | Reply

  5. Excuse me if I ask a stupid question but what if the flat-earther takes your ironic comment literarily? Irrational people have a tendency to mistake their own automatic thinking for rationality.

    Comment by Lena Synnerholm — August 29, 2016 @ 3:51 am | Reply

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