"...the first-ever Flat Earth International Conference drew about 800 people from across — not around — the world to Raleigh, N.C." (Boston Globe, 11/20/17)
Recent news coverage of modern flat-earthers, noticed in NBA players, a popular rapper, and most recently in a gentle probing of a New England man by the Boston Globe, reminded me of my long-ago days teaching seventh-grade earth science.
I had heard something of the Flat Earth Society, and its members' insistence that they were not moved by "hearsay evidence" such as the testimony of astronauts, or photos or videos from space (which could be faked). This seemed to me a laudable spirit, and in one class project I tried to inculcate a little healthy skepticism into students who were accustomed to believing whatever they were told. (I frequently fielded questions about UFOs from students who had seen a "special" on TV, for example, and also conducted nifty class experiments to debunk astrology.) Acknowledging that direct evidence was more trustworthy, we therefore worked through a few simple observations available to earth-bound observers, culminating with students writing letters to the Society's then-president Charles K. Johnson, pretty much proving that the earth is, indeed, round.
My class focused on observations that did not require trust in others, nor expensive travel. Students wrote that sailors have, for centuries, judged the distance to another ship by how much is visible above the curve of the ocean's surface with such terms as "hull down" and "topsails down." They pointed out that in a lunar eclipse, the earth's shadow on the moon is always curved. Comparison of airline flight routes with a flat earth map would reveal that international flights typically follow "great circle" routes that are only possible on a curved earth. The stars visible in the night sky not only change though the seasons, but are also different in different latitudes*--which could only occur on a round earth. (That bends the rule about limiting travel expenses.) Delighted to discover that Johnson had married an Australian, we urged him to telephone his in-laws and hear that they were experiencing the opposite time of day.
Flat earthers have answers (of a sort) for some of these. A lunar eclipse is the shadow not of the earth, but of a small, round object orbiting the sun too closely to be visible. (I suppose it's just a coincidence that the movements of this object coincide perfectly with those of the earth.)** The apparent sinking of a ship as it nears the horizon is (somehow) the result of perspective.
Unfortunately, we never heard back from Mr. Johnson; I learned a little later that the organization was moribund even then, and Johnson himself fell on hard times, and died a few years after our letter-writing ended.
I didn't realize when I was teaching seventh grade that most flat earthers imagined that the sun moved in a circle over a flat earth in which the north pole was in the center while the Antarctic formed the edge. This would be to easy to disprove: the sun would move closer and farther, but never set below or rise above the horizon. Their explanations of this simplest observation are the least convincing of a pretty unconvincing bunch: something about the sun's changing distance being exactly countered by some sort of perspective effect. (Other explanations are simply gobbledygook.) A non-mainstream site called The Creator's Calendar posits "Three Unanswerable Objections to the Flat Earth Theory." It does a pretty convincing job, while treating adherents ("The Honest of Heart, as they seek for truth as for buried treasure") with sympathy and respect.
Nor did I realize that flat-earthers invoked Einstein to explain apparent gravity. They explain that, while some objects exert gravity, the earth does not; we feel instead the upward acceleration of the earth at a rate of 9.8 meters per second per second.*** (Einstein, in his theory of general relativity, showed that acceleration could perfectly mimic gravity.) A nifty idea, except that, from a dead stop, the earth would exceed the speed of light in less than a year!
One of the striking things about flat eartherism is its skepticism of the entire scientific framework. One of the key questions about any new discovery is how it fits in with established knowledge; a new discovery that requires overturning long-established frameworks warrants enormous resistance: it is much more likely that the new discovery is bogus, than that a much more-established and coherent framework is. Believers in a flat earth must discard much more than simply recent space travel--the whole of astronomy and cosmology, universal gravitation, and even classical physics all go out the window.
**If that isn't enough, orbiting objects move faster--not slower--the nearer they are to their "primary," so the earth could not possibly keep pace with a small object orbiting nearer the sun.
***propelled by dark energy, no less!
Recent news coverage of modern flat-earthers, noticed in NBA players, a popular rapper, and most recently in a gentle probing of a New England man by the Boston Globe, reminded me of my long-ago days teaching seventh-grade earth science.
I had heard something of the Flat Earth Society, and its members' insistence that they were not moved by "hearsay evidence" such as the testimony of astronauts, or photos or videos from space (which could be faked). This seemed to me a laudable spirit, and in one class project I tried to inculcate a little healthy skepticism into students who were accustomed to believing whatever they were told. (I frequently fielded questions about UFOs from students who had seen a "special" on TV, for example, and also conducted nifty class experiments to debunk astrology.) Acknowledging that direct evidence was more trustworthy, we therefore worked through a few simple observations available to earth-bound observers, culminating with students writing letters to the Society's then-president Charles K. Johnson, pretty much proving that the earth is, indeed, round.
My class focused on observations that did not require trust in others, nor expensive travel. Students wrote that sailors have, for centuries, judged the distance to another ship by how much is visible above the curve of the ocean's surface with such terms as "hull down" and "topsails down." They pointed out that in a lunar eclipse, the earth's shadow on the moon is always curved. Comparison of airline flight routes with a flat earth map would reveal that international flights typically follow "great circle" routes that are only possible on a curved earth. The stars visible in the night sky not only change though the seasons, but are also different in different latitudes*--which could only occur on a round earth. (That bends the rule about limiting travel expenses.) Delighted to discover that Johnson had married an Australian, we urged him to telephone his in-laws and hear that they were experiencing the opposite time of day.
Neill DeGrasse Tyson posted a similar image, with a caption something like, 'eclipse the like of which no flat-earther has seen, ever.' (Photo from Oddstuffmagazine.com)
Flat earthers have answers (of a sort) for some of these. A lunar eclipse is the shadow not of the earth, but of a small, round object orbiting the sun too closely to be visible. (I suppose it's just a coincidence that the movements of this object coincide perfectly with those of the earth.)** The apparent sinking of a ship as it nears the horizon is (somehow) the result of perspective.
Unfortunately, we never heard back from Mr. Johnson; I learned a little later that the organization was moribund even then, and Johnson himself fell on hard times, and died a few years after our letter-writing ended.
The curvature of the earth is, in fact, directly observable in some circumstances. A hero of mine, Darwin friend and natural selection co-discoverer Alfred Russel Wallace took on a flat-earther in his own day. The field of battle was a British canal that ran straight and true for six miles--adequate for detection of curvature under the right circumstances. Wallace mounted marks on convenient bridges at fixed heights above the water and found that these marks did not line up visually, showing that the surface of the canal was curved. (In so doing, Wallace won a wager, but the loser began a campaign of slander and filed a expensive law suit, and Wallace was never able to collect.) The Bedford Canal is again a battle-ground, with newer flat-earthers declaring that the canal is, actually, flat.
When you look at the image above, other inconsistencies will occur to you!
(from flatgeocentricearth.wordpress.com)
Nor did I realize that flat-earthers invoked Einstein to explain apparent gravity. They explain that, while some objects exert gravity, the earth does not; we feel instead the upward acceleration of the earth at a rate of 9.8 meters per second per second.*** (Einstein, in his theory of general relativity, showed that acceleration could perfectly mimic gravity.) A nifty idea, except that, from a dead stop, the earth would exceed the speed of light in less than a year!
(Image from albertonrecord.co.na)
One of the striking things about flat eartherism is its skepticism of the entire scientific framework. One of the key questions about any new discovery is how it fits in with established knowledge; a new discovery that requires overturning long-established frameworks warrants enormous resistance: it is much more likely that the new discovery is bogus, than that a much more-established and coherent framework is. Believers in a flat earth must discard much more than simply recent space travel--the whole of astronomy and cosmology, universal gravitation, and even classical physics all go out the window.
That's because scientific knowledge is not a collection of disconnected facts, but a (mostly) strong framework in which major elements complement and support each other. (One fundamental “break” in this framework has long concerned physicists: Einstein’s general theory of relativity--whose validity is very well supported by diverse evidence--does not appear to connect with quantum physics--which is also very well supported by diverse evidence.)
But flat earth "theory" is not only inconsistent with this framework--it is also inconsistent with itself. Objects have gravity (which explains their orbits), but the earth does not. The sun and moon have gravity, but move in circles over the surface of the earth in a way gravity could not explain. Acceleration mimics gravity for the earth in accordance with Einstein, but Einstein shows that no physical object can reach the speed of light (and even approaching that speed is very difficult). The sun and moon either approach and recede without changing their apparent size, OR they behave like spotlights shining first in one place and then another--but without the visual appearance such a light would show. And so on.
Why my quotation marks on flat earth "theory?" Common usage notwithstanding, THEORY is the highest level of scientific knowledge. Any theory must not only be supported by a LOT of evidence, but that evidence must converge from different disciplines. (Evolution by natural selection, for example, fits this bill very well, since it is solidly supported by fossils, the anatomy of modern species, genetics, molecular biology, and modern field research.) Finally, the theory must be in accord with established knowledge. (On the very rare occasions they aren't in accord, a scientific revolution is in order! Such a revolution occurred in geology when the theory of plate tectonics overturned some of the underpinnings of geological thought a half-century ago.)
Scientific theories fit all three criteria: a lot of evidence, from diverse directions, converging toward an explanation that accords well with the established framework. Flat earth "theory" plainly fits none of them.
Why, then, do some people take it seriously?
*I remember seeing the Southern Cross (never visible from nearly all the continental US), as well as the Large and Small Magellanic Clouds (really only clear from the southern hemisphere) when I was a Peace Corps Volunteer in Samoa many years ago. But you don't need to travel at all: as the stars appear to move with the rotation of the earth, they do not "recede" out of our sight as they would if they hovered low over a flat earth--otherwise the constellations would appear to shrink; another simple disproof of a flat earth. But flat earth "theory" is not only inconsistent with this framework--it is also inconsistent with itself. Objects have gravity (which explains their orbits), but the earth does not. The sun and moon have gravity, but move in circles over the surface of the earth in a way gravity could not explain. Acceleration mimics gravity for the earth in accordance with Einstein, but Einstein shows that no physical object can reach the speed of light (and even approaching that speed is very difficult). The sun and moon either approach and recede without changing their apparent size, OR they behave like spotlights shining first in one place and then another--but without the visual appearance such a light would show. And so on.
Why my quotation marks on flat earth "theory?" Common usage notwithstanding, THEORY is the highest level of scientific knowledge. Any theory must not only be supported by a LOT of evidence, but that evidence must converge from different disciplines. (Evolution by natural selection, for example, fits this bill very well, since it is solidly supported by fossils, the anatomy of modern species, genetics, molecular biology, and modern field research.) Finally, the theory must be in accord with established knowledge. (On the very rare occasions they aren't in accord, a scientific revolution is in order! Such a revolution occurred in geology when the theory of plate tectonics overturned some of the underpinnings of geological thought a half-century ago.)
Scientific theories fit all three criteria: a lot of evidence, from diverse directions, converging toward an explanation that accords well with the established framework. Flat earth "theory" plainly fits none of them.
Why, then, do some people take it seriously?
**If that isn't enough, orbiting objects move faster--not slower--the nearer they are to their "primary," so the earth could not possibly keep pace with a small object orbiting nearer the sun.
***propelled by dark energy, no less!
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