“I drive from Florida to California all the time, and it’s flat to me. I do not go up and down at a 360-degree angle, and all that stuff about gravity, have you looked outside Atlanta lately and seen all these buildings? You mean to tell me that China is under us? China is under us? It’s not. The world is flat.” -Shaquille O’Neal

Perhaps the reason so many of us don’t quite believe the Earth is round is because we can’t directly see it for ourselves. At any point we happen to be on the Earth’s surface, when we look around in all directions, it appears to be flat. On his great sea voyage, Magellan and his crew never once perceived the Earth to be round, yet they circumnavigated the entire globe after enough distance had been traveled.

As ships sail farther away, a larger fraction of their hulls, sails and masts become obscured by the horizon, due to the curvature of the Earth. Image credit: stealth_sly of Pixabay.

As ships sail farther away, a larger fraction of their hulls, sails and masts become obscured by the horizon, due to the curvature of the Earth. Image credit: stealth_sly of Pixabay.

Shaq may never have noticed the Earth’s curvature at any point along his I-10 drive from Florida to California, but if he had just gone a little farther — into the ocean — he could have seen it for himself. The effects of Earth’s curvature will cause buoys to appear more distant, closer to the horizon, and eventually to slip over it, depending on your height above sea level and your distance to the buoy.

When you're at the optimal distance to measure the Earth's curvature, a buoy's bottom will be visible right on the horizon line. For a human at sea level, that will never be as much as six kilometers from the buoy. Image credit: mark_az of Pixabay.

When you’re at the optimal distance to measure the Earth’s curvature, a buoy’s bottom will be visible right on the horizon line. For a human at sea level, that will never be as much as six kilometers from the buoy. Image credit: mark_az of Pixabay.

Measure those two things correctly, and you’ll not only know that the Earth is round, you’ll be able to deduce the size of our world. Come find out how!

Comments

  1. #1 Wow
    March 28, 2017

    It isn;t flat. Drive to the Rockies or Grand Canyon (other obviosu deviations from flat are available).

    Oh, you mean “mostly flat”.

    Well, a really REALLY big sphere, some thousands of km in radius, would, to a 2m tall human be “mostly flat”.

  2. #2 Wow
    March 28, 2017

    “a buoy’s bottom will be visible”

    Is this why americans pronounce it “booey”?

  3. #3 Wow
    March 28, 2017

    Spin a bucket of water vertically round and round.

    Are you telling me that sometimes the water is BELOW the bucket???? BELOW????

    Get a glass of water. Put on it a flat waterproof card. Pick it up and holding the glass and card carefully together, turn it upside down. Take the card away carefully. Are you telling me the water won’t fall out?!?!??!?!

    Bah, the same people who try to tell me that are the same sort who think that China is UNDER US!

    Just makes no sense to think that water can defy “falling down”. It clearly falls down, else rivers would run upstream!

    And clearly springs must produce water since there’s no way water goes UP HILL. Just nonsense. Water is created from water springs ex nihilo to run to the sea.

  4. #4 eric
    March 28, 2017

    It isn;t flat. Drive to the Rockies or Grand Canyon (other obviosu deviations from flat are available).

    Shaq almost certainly takes the I-10 ‘southern route’ across the US, since he’s going from LA to Florida. That route is indeed extremely flat (and boring). Approximately half of that drive is just going through Texas, where you could prop a board under your steering wheel, go to sleep, and you’d probably be okay (obviously an exaggeration but not much of one).

    He’s still blatantly and obviously wrong, but he’s not driving through canyon territory or the Rockies. Instead, he’s driving through territory that makes you wish you could come to the end of the flat Earth, if only to relieve the monotony.

  5. #5 Frank
    Omaha,NE
    March 28, 2017

    Sun, Moon and the planets visible with binoculars are all being round means Earth must be round too.
    I think ISS in orbit can be seen with small telescope also.
    If Earth is not round then how it can stay in orbit?

  6. #6 Sinisa Lazarek
    March 28, 2017

    “Perhaps the reason so many of us don’t quite believe the Earth is round is because we can’t directly see it for ourselves.”

    That seems a really lame reason. I can’t see you directly so I should believe that you are a bot and all this is just a huge NASA ploy. Or anything else for that matter.. how many things in this world we can’t see directly and rely on others to provide pictures/videos as evidence so that we may see as well. Plus, most of those who think earth is round are the same ones who believe in some deity, and they can’t see that either. Nah… Shaq is just dumb and so are sadly some others.

  7. #7 Sinisa Lazarek
    March 28, 2017

    ups… sorry.. the last part should be: “.. those who believe earth is FLAT…” my bad 😀

  8. #8 Michael Mooney
    March 28, 2017

    The science of relativistic observational differences and “equal validity for all frames of reference” (SR) insists that a pancaked Earth is an “equally valid” description. Maybe it’s time to address length contraction as applied to Earth, Ethan.

  9. #9 Frank
    Omaha,NE
    March 28, 2017

    #8 Nobody have to explain anything to you. World does not lose anything if you have any wrong ideas on anything.

  10. #10 dean
    March 28, 2017

    “The science of relativistic observational differences and “equal validity for all frames of reference” (SR) insists that a pancaked Earth is an “equally valid” description. Maybe it’s time to address length contraction as applied to Earth, Ethan.”

    MM, despite your claims to understand relativity it is clear you have no clue.

    Everything in the discussion has people in the same frame of reference. The issue you cite doesn’t come up.

    How did you miss that? Intentionally?

  11. #11 dean
    March 28, 2017

    “Shaq is just dumb…”

    To be honest, I have (since this initially came up) heard him say that his first comment was a joke – he was commenting on what he saw driving cross country and (claimed) that he had said, jokingly, “If everything I see when I drive looks flat why should I believe the world is round?”

    Whether that comment is factual or a lame attempt to cover himself I cannot say.

  12. #12 eric
    March 28, 2017

    he was commenting on what he saw driving cross country and (claimed) that he had said, jokingly, “If everything I see when I drive looks flat why should I believe the world is round?”

    Somewhere in the ‘Earth is flat’ commentary is probably a good joke about East Texas. But if so, Shaq clearly didn’t pull it off.

    Regardless of whether he meant it and is now just saving face, or it was a really poorly executed bit of humor, I’m willing to cut the guy some slack. I’d say to him: use your celebrity now to support good science, and we can drop the earlier mention and move on.

  13. #13 Sinisa Lazarek
    March 28, 2017

    in defense of Shaq now.. 🙂 he is/was a superb athlete and professional when he was playing. And being in an apex of any sport just like anything else requires tremendous sacrifice and focus on one thing. In terms of him as a professional, my hat’s of to him and every other top athlete. But that sadly comes at a price of not leaving much if any room for learning or time to care much for other than game and points. So I might have been a bit harsh… cause he could have made a same comment if he want to talk about finer points of 3rd quarter offense strategies and I looked at him like a goat.

  14. #14 PJ
    Perth, west Oz
    March 28, 2017

    Perhaps someone could explain the effects of gravity of a discus shaped planet. Not a pretty sight!

  15. #15 Michael Mooney
    March 28, 2017

    Dean (#10): “Everything in the discussion has people in the same frame of reference. The issue you cite doesn’t come up. ”

    I just brought it up. The discussion is about whether Earth is “really” flat or spherical. Deal with it.

  16. #16 dean
    March 28, 2017

    Mm, your comment has nothing to do with this discussion. Neither does your lack of understanding of relativity.

  17. #17 Michael Kelsey
    SLAC National Accelerator Laboratory
    March 28, 2017

    @Michael Mooney: The discussion _is_ about whether Earth is really flat or spherical (without any ignorant scare quotes). It’s NOT about relativity, or your ignorance thereof.

    The curvature of the Earth is a directly measurable quantity, which can be done by any competent surveyor. Survey a large triangle (like one piece of a transect), ideally one with arms at least several kilometers long. Measure the three angles and add them together.

    If the Earth is flat like a pancake, the sum of the three angles will be 180 degrees, within the uncertainties of your measurement. If the Earth is “spherical” (even roughly: it could be egg shaped, or football shaped, or balloon shaped), then your angles will add up to more than 180 degrees.

    If you are ambitious, you can survey multiple triangles, and you will discover that all of them are systematically “too large” with respect to Euclidean geometry.

    That is an simple, objective measurement which anyone from the 17th Century on could have done. No spacecraft necessary. Just knowledge and competent skill. Both of which are demonstrably missing from one of the commenters here.

  18. #18 Michael Mooney
    March 28, 2017

    Michael Kelsey,
    You misunderstand me. I have always argued (against SR theory) that Earth is really in fact nearly spherical. So when Ethan proposed, in this post, to educate Shaq about this established fact … and any other “flat Earthers” out there… I joined him to agree that any flat Earth belief is wrong… including SR’s theory that a “pancaked Earth” is a valid description, i.e., if a high speed traveler might see it that way and claim that as “equally valid,” as SR does.

  19. #19 Omega Centauri
    March 28, 2017

    dean @11, thats what I thought, he is just having fun with us.

    Of course Ethan needed to use it for the post, and that’s perfectly fair.

    When I was younger I had been told that Columbus’s mistake (thinking the world was round but a lot smaller than it really is), was caused by observing ships vanish over the horizon. Supposedly he was fooled by waves. I doubt that’s really the reason, but in any case among the European educated at the time, it was generally taken that the earth is round, and Columbus used a very much too small radius that wasn’t much in vogue. If the Americas weren’t there, he never would have made it to Asia (too far).

  20. #20 Omega Centauri
    March 28, 2017

    All of these methods of demonstrating that the earth is round, and estimating the radius require the ability and willingness to construct a mathematical model, and then look for observable consequences. Only a small fraction of the population is winning/able to do that.

  21. #21 David
    March 29, 2017

    Computing the radius of the earth by observing objects vanish over the horizon is inaccurate due to atmospheric refraction. Even minor temperature differences over a few feet can have a dramatic effect; for example this produces mirages in the desert.

  22. #22 Sinisa Lazarek
    March 29, 2017

    @ Michael M

    instead of crying here for weeks, why don’t you do some work instead. Prove that either speed of light is not same in all reference frames, or that not all reference frames are equally valid (prove it mathematically or logically). Otherwise you’re crying over nothing other than your fancies.

  23. #23 Keith P.
    March 29, 2017

    Shaq also tried to play “peanut butter” as a dairy product in a game of Scattergories (Curb Your Enthusiasm). I’m having my doubts that Larry David wrote that scene…they may have really been playing!

  24. #24 eric
    March 29, 2017

    why don’t you do some work instead. Prove that either speed of light is not same in all reference frames…

    I know! He could:
    1. Get a laser.
    2. Shoot it through a half-silvered mirror to split the beam at right angles
    3. Reflect each of those beams off a second mirror back to the original mirror, and then from there to the same detector.
    4. Measure light flight time as a function of angle.
    5. Put the whole thing on a rotating table, so you can check all angles.

    Since the Earth is both rotating and moving around the Sun (which is moving around Galactic center, etc…), if the speed of light is not the same in all reference frames then it’s speed between mirrors oriented in the direction of the Earth’s motion will be different than it’s speed between the mirrors oriented at right angles to the Earth’s motion.

    He’s even got the right initials for the experiment. 🙂

  25. #25 Wow
    March 29, 2017

    “US, since he’s going from LA to Florida. That route is indeed extremely flat (and boring).”

    Though since he can see the sun, and that HAS to be further away than LA from Florida, why can’t he see LA? Or at least the smog, all along the route?

  26. #26 Wow
    March 29, 2017

    “He’s still blatantly and obviously wrong, but he’s not driving through canyon territory or the Rockies. ”

    That’s why I told him to take that drive to prove it’s not flat.

  27. #27 Wow
    March 29, 2017

    “If Earth is not round then how it can stay in orbit?”

    And why doesn’t all the air fall off?

  28. #28 Rohit Agarwal
    India
    March 29, 2017

    The buoy experiment proves that the earth is not flat. It still cannot prove that it is a sphere. Earth could as well be a Ellipsoid with a huge skew / bulge or even could be like an astroid. Is there any other experiment that can be performed without going to space to prove its sphere?

  29. #29 Frank
    Omaha,NE
    March 29, 2017

    And why still nobody found the edge?
    Also any rich person could take a private plane ride to fly in the same direction and come back to starting point.

  30. #30 Wow
    March 29, 2017

    Why does the sun not fall down when it sets and never rise again? Does gravity only act on a whim?

  31. #31 Sean T
    March 29, 2017

    MM,

    Besides, who ever said that the earth is pancake shaped in ANY reference frame. Maybe to an approximation, but in reality, the observer moving an near light speed with respect to the earth would still measure curvature of the earth’s surface. It would not be mathematically flat in any reference frame. It is true that the rapidly moving observer would measure a smaller radius in the direction of travel than he would in an orthogonal direction, but the surface of the earth still would be curved.

    Of course, the statement that the earth is really round is really just shorthand for “the proper shape of the earth is (nearly) round”, where the term “proper shape”, much like the terms proper length and proper time, is defined as the shape as measured by an observer in a commoving reference frame. The earth really is round in a reference frame that is not moving at an appreciable fraction of the speed of light. In other reference frames, it really does have a different shape, one that is anisotropic, unlike its shape in a commoving frame.

  32. #32 Wow
    March 29, 2017

    It also has to be in the same accelerating frame. Outside the sun’s gravity, we’d see a very slightly different shape of earth, even apart from the geodesic effect of gravity itself. Just like, out here, we see a change to the “proper orbit” of Mercury, because we’re not in the same inertial frame as they are, the planet being much closer to the sun and in a more extreme gravity well.

  33. #33 Michael Mooney
    March 29, 2017

    Sean T: “Earth really is round”… period. It’s shape in the real world doesn’t depend on reference frame. SR is all about observational differences… **appearances**… from different reference frames. None of that changes the **fact** that Earth is nearly spherical, just like the Sun and Moon and other stars and planets.
    ” it really does” **appear to have** (according to SR) “a different shape … in a reference frame that is not moving at an appreciable fraction of the speed of light.”

    Objective realism (for which I speak) does not argue against that. “Ask Ethan.” He once agreed but will not follow up on it.

  34. #34 Michael Mooney
    March 29, 2017

    Edit: It really does **appear to have** (according to SR) “a different shape” … in a reference frame that IS moving “at an appreciable fraction of the speed of light.”

  35. #35 Wow
    March 29, 2017

    “Sean T: “Earth really is round”… period.”

    Really not.

    The geodesic is described currently with 12 parameters. A sphere only needs two.

    It’s not round. Period.

    “Objective realism (for which I speak) does not argue against that.”

    You speak for yourself. Nobody else. You speak for YOUR interpretation of objective realism. For a start you even admit you can’t do the maths, therefore you are incapable of speaking for it.

    ” it really does” appear to have (according to SR) “

    And appearance, if there’s no way to tell the difference between that and another view, is reality. There’s no other way, unless you go back to platoism (which set science and even engineering back nearly 2000 years) that insists that your thinking about reality is more real than reality’s opinion via experiment and evaluation.

    If you are moving in a spacesuit, adrift from your parent craft, and outside all visibly moving objects to refer to, what is your velocity?

    Why does that change if you put a moving point in the situation? Does meeting another abandoned astronaut coming the other way change your velocity? Your direction?

    No? Then your opinion on your velocity is not objective reality, your speed and direction are not there in and of themselves.

  36. #36 Wow
    March 29, 2017

    The shape of earth changes while the moon revolves around us, while we revolve around the sun and while the planets change their location with respect to us. For a more extreme version, see Enceladus.

    And the surface is not even at the equilibrium point, it’s more oblate than it should be, but the solidity of the planet doesn’t let the matter flow freely and reach true equilibrium.

    If I measure a different time than you, why is YOUR time real?

    If I measure distances being shorter, why is YOUR yardstick real?

  37. #37 Michael Kelsey
    SLAC National Accelerator Laboratory
    March 29, 2017

    @Wow #34: You wrote: <>

    A minor nit pick: “Round” is not a synonym for spherical. It is a synonym for curved. A rugby ball in round, but not spherical. An egg is round, but not spherical. A torus is round but not spherical. The Earth is round, but not spherical.

  38. #38 Wow
    March 29, 2017

    Aye, true enough, but since there’s nobody here claiming flatworld, the meaning was clear.

  39. #39 Sinisa Lazarek
    March 29, 2017

    MM still has to accept the fact that he’s not debating science, however much he wishes to be doing so. He’s not saying that math is wrong, he’s not saying that experiments are wrong (or at least not directly), so at the end of the day he can’t fault science. All he’s really doing is saying, I don’t like how that sounds and what it means. Well… tough luck. Put forth some science or stop bitchin’

  40. #40 Wow
    March 29, 2017

    And with regards to mooney, he claims it has some unchanged shape, spherical/round, but he’s not willing (or able) to do the maths to show what forces exist to make the hydrostatic shape of a planetary body appear spherical in “objective reality”.

    Because in either an accelerating or relativistic frame of reference, the forces need to be worked out with the correct (even for OR’s “correct” version) maths.

    I.e. if “time changes” but not space, according to mooney, “in objective reality”, then the energies are no longer comensurate.

    Some fairly simple maths should show how difficult it gets to square THIS particular tetrahedron….

  41. #41 dean
    United States
    March 29, 2017

    Michael Kelsey:
    ““Round” is not a synonym for spherical. It is a synonym for curved.”

    Is it in physics? I never encountered its use that way in the math courses I had, undergrad or grad: curved was used for the general case, round was always related to circular or spherical things.

  42. #42 ctsciencenut
    CT
    March 29, 2017

    I think Shaq has a responsibility as a role model to think about his young fans before spreading blatantly false information.The most important implication of Shaq’s statement is that we as a society should be promoting trust in science and scientific thinking, not dealing in conspiracy theories.
    http://www.ctsciencenut.com

  43. #43 Michael Mooney
    March 29, 2017

    Regarding Wow #39: “I.e. if “time changes” but not space, according to mooney,…”

    I have never said “time changes.” We all acknowledge that clocks change (slow down) as timekeepers after acceleration to higher velocities or exposure to more force of gravity. Do not put words in my mouth.

  44. #44 Wow
    March 29, 2017

    “I have never said “time changes.””

    You have. You said that time changes for the observer but that distances don’t change, ergo the earth remains a sphere, was and is still, your insistence.

    I’m putting nothing in your mouth you didn’t put there, so take your complaint and shovel it.

  45. #45 Michael Mooney
    March 29, 2017

    Ps: The speed of light remains constant in space. It conveys images. They would theoretically be observed and measured differently as the frame of reference approaches the speed of light. (Contracted in the direction of the the approaching “observer.”)
    The discussion here is still about “apparent” vs “real.” A flat Earth is not “real,” … just apparent in very “special” theoretical circumstances.

  46. #46 Michael Mooney
    March 29, 2017

    I register a complaint against Wow for this nasty comment:

    “… so take your complaint and shovel it.”

  47. #47 Wow
    March 29, 2017

    ” It conveys images. ”

    No, it imparts energy to charged particles. Images require interpretation by an observer with a visual cortex. IR is the same stuff as light, but creates no image to us. A gamma ray is a photon too, but there’s no image there: it is the result of an atomic decay.

    “I register a complaint against Wow for this nasty comment:”

    How many have registered a complaint about your nasty comments?

    And tell me when “shovel” became a dirty word.

  48. #48 Wow
    March 29, 2017

    “They would theoretically be observed and measured differently”

    Why does it require a human observer?

    And why only “theoretically”? If you don’t even know if there would “appear” to be contraction, why do you say “Oh, it would only appear that way”?

    Tell us all, too, about how only timepieces will show a slowdown of time. How does that work. How does a clock know that it’s supposed to show a different elapse? How is this elapse slowdown mechanised.

    If you do not know any of this, you know nothing and instead of bleating on here you should go and educate yourself or shut up.

  49. #49 Ragtag Media
    United States
    March 29, 2017

    Go on and get in Shaq’s face and tell him he is wrong and see if you get flattened.. LOL

  50. #50 Wow
    March 29, 2017

    Yeah, right. I’m safe enough. He’s got a lot of money and he’s not dumb enough to start an assault charge that could, from your “description” be GBH easy.

    Not to mention he’s probably been told that and worse.

    He’s not a psycho rightwinnutjob who has invisibly thin skin.

  51. #51 eric
    March 29, 2017

    SL:

    MM still has to accept the fact that he’s not debating science, however much he wishes to be doing so.

    He says (or at least implies) that he thinks SR time dilation is a function of prior acceleration rather than relative speed. That’s arguing physics. Also remember that when confronted with the observed behavior of muons produced in the atmosphere, he did indeed say that the experiments were wrong (because the data doesn’t fit with his dilation-comes-from-acceleration hypothesis); that laboratory measurements of the muon half-life must be wrong.

    Secondly, he keeps stating that time doesn’t dilate, only clocks do. That seems to be arguing physics, though it’s a fuzzier case since he seems to accept that fundamental physical processes can slow down too, not just things like mechanical clocks. Ultimately there may be a distinction without a difference here, or maybe he will claim some testable physical interaction won’t slow down (as measured by the observer) in a relativistic frame of reference.

  52. #52 Wow
    March 30, 2017

    He’s only refused that time slows down because he sees, even without maths he can neither do nor wants to, that there’s a problem with power and energy if it does. Yet he still doesn’t see that if clocks measure things differently to time then there’s an even worse problem.

    Because, as usual, he doesn’t bother to do the thinking before the claiming.

    PS I’d forgotten about the dilation from acceleration too.

  53. #53 John
    Baltimore
    March 30, 2017

    @ #49 Ragtag Media,

    “… get in Shaq’s face and tell him he is wrong …”

    That’s one of the differences between the real world and this electronic one.

    Responsible people would think twice, and perhaps more, before getting into Shaquille O’Neal’s face, for they understand that the price for doing so can be prompt and physically painful. Civil behavior is protected, while gratuitous antagonism is punished.

    Once protected from the physical consequences of misbehavior, be it in an automobile or behind a keyboard, some behave irresponsibly, to the detriment of all. It is only when they become aware their aberrant behavior is threatening their existence that they resume civil behavior.

    This virtual world is not without its downside.

  54. #54 Wow
    March 30, 2017

    Uh, Shaq isn’t a violent thug. And again over the internet, a “hard man” is safe from having to actually back up their tough rhetoric, safe in their underpants and basement.

  55. #55 Sinisa Lazarek
    March 30, 2017

    @ eric

    He might get less flac if he changes it to Subjective Mooneism instead of calling it objective realism. There’s nothing objective in his views and they don’t have much to do with reality.

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