Great Circles are Straight Lines (as much as that's possible on a sphere)

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  • @gennoveus
    @gennoveus 4 роки тому +3

    Your videos, no matter the subject, never fail to be fascinating. Thank you!

    • @okreylos
      @okreylos  4 роки тому

      I appreciate it. This is not a video I planned to make, but here we are.

  • @0LoneTech
    @0LoneTech 2 роки тому +1

    I agree that the navigational textbook description was confusing. For some reason they were assuming rhumb lines as the base case. In practice, few travels go so far or close to the poles that the difference is obvious, and only one mode of travel (orbital) goes very straight without control inputs.

  • @tkolkebeck
    @tkolkebeck 3 роки тому +4

    Excellent presentation. I wa curious on your opinion. I have a family member who believes in FE. I asked them to give me a reference to any pilot who believes in FE. She finally gave me a name of a guy who is 74 yrs old and a retired pilot. When I emailed him, he admitted that although he has like 17,000 flight hours, he has never piloted an aircraft across an ocean or done long-distance flying, therefore he never utilized great circle routes. I think THAT is the only type of pilot that FE could throw the wool over. My brother is a commercial airline pilot and flies great circle routes in n. hemisphere all the time. Sad we are having this argument in 2021... :o(

  • @holy3051
    @holy3051 4 місяці тому

    OMG. I have trying to find a simulation showing this. Every single info source I checked insist that the pilot need to make constant direction changes but my logic told me that wasn't right.
    I was no wrong.
    People never try to think for themselves, they just believe what the other people tell.

    • @okreylos
      @okreylos  4 місяці тому

      It's a bit more complicated than that. Geometrically, a great circle path is a straight line, meaning you don't have to turn to stay on it.
      But: how do pilots determine whether they are flying in a straight line or not? Planes always yaw left/right without the pilot's interaction, and pilots continuously need to counteract those random course changes. They do that by using their heading indicators, which are basically compasses and show the angle towards north.
      The problem is that, when flying on a great circle route that is not the equator or a meridian, your compass direction will change continuously. So when they want to fly along a great circle route, pilots have to continuously change course, as in their heading angle relative to north, to stay on a straight line.
      To be clear, by "change course" I don't mean "turn." I mean that as they are flying straight, their compass direction changes, and they need to be aware in which direction they have to fly at any point in order to make the correct corrections. That's why great circle routes are hard to plan and hard to follow without on-board computers or GPS.

  • @davidviner5783
    @davidviner5783 3 роки тому +2

    Very well presented and informative. I would like to hear a flat-earther's response to this video.

  • @Toastmaster_5000
    @Toastmaster_5000 4 роки тому

    Interesting. Makes sense, but it isn't something I really ever thought about.

  • @sheldonmcpherson2700
    @sheldonmcpherson2700 3 роки тому

    thanks!!

  • @AK-jt8gl
    @AK-jt8gl 2 роки тому

    Could you (please) show us (if/when you are inclined to do so) why the Cooke Passage as described here: ua-cam.com/video/S5HgaVZwvCM/v-deo.html isn't actually a 'straight path' - I believe this has been proven to NOT be a straight path since it isn't in fact a great circle path. What I am trying to grasp and hopefully visualize is why a non-great-circle path isn't a straight path, because conceivably, any path which is made by an intersection of a sphere and a plane (in my limited understanding of the geometry) would be a 'straight path', but is in fact NOT.

    • @okreylos
      @okreylos  2 роки тому +1

      "why the Cooke Passage ... has been proven to NOT be a straight path"
      I would have to find a precise geometric definition of that passage and then test whether all its points lie on a plane that also contains the center of Earth, which is a ton of work that I'm not going to do. :)
      That said, I'd be happy to address your other questions.
      "why a non-great-circle path isn't a straight path"
      When you follow a non-great-circle path, you have to turn left and/or right to stay on the path. To follow a great-circle path, you do not have to turn ever.
      "any path which is made by an intersection of a sphere and a plane (in my limited understanding of the geometry) would be a 'straight path'"
      No, that is not the case. Imagine standing on a sphere (not a big ask, given that you are standing on one right now), and intersect the sphere on which you are standing with a plane that is orthogonal to your local "up" direction, and just a very short distance underneath your feet. The intersection of that plane with the sphere will be a circle with a radius of a few meters or so, and in order to walk along that circle, you will have to continuously turn either left or right, because it is literally a circle on the ground. So it is not a straight path. The only intersections of a plane and a sphere that are straight paths are those where the plane contains the sphere's center point. And those are exactly the great circles.

  • @lavarburton1849
    @lavarburton1849 Рік тому

    You forgot to mention that for any given route, the "miles" that are compensated for being "radial", when extrapolated to the whole supposed circumference of the "globe" is 2.3 times the distance. Why? Because it's not a globe.
    It's so funny that now that people have proved the earth is flat using lasers, the globe-earthers now say lasers bend the OPPOSITE way of the curvature of the earth. What a joke. Aristotle thought eels were created by mud.

    • @rawhide_kobayashi
      @rawhide_kobayashi Рік тому

      what is that even supposed to mean? from a globalist point of view, the laser does not bend... the laser goes straight, while the curved earth falls away from the laser.
      now, technically, from that point of view, the earth slightly pulls the light towards it, because gravity affects photons, which would be measurable with extremely precise instrumentation, but that's beyond the scope of the basic point of such an experiment.

  • @shabana1728
    @shabana1728 2 роки тому +1

    100 th like!!

  • @WildPhotoShooter
    @WildPhotoShooter 4 роки тому +3

    Flat Earthers refuse to see just how simple this is.

    • @okreylos
      @okreylos  4 роки тому +5

      Interestingly, the disagreement that led me to create this video was with a globe Earther.

    • @WildPhotoShooter
      @WildPhotoShooter 4 роки тому

      @@okreylos Astounding ! What was wrong with him ?

    • @okreylos
      @okreylos  4 роки тому +1

      Nothing wrong per se, but he (assuming it's a guy) doesn't see how your compass heading could change without you turning left/right. I think he's forgetting that a compass needle points towards the poles, two actual points in space a finite distance away. Even when not on a globe, when traveling in a straight line, the direction to any fixed point that is not infinitely far away will change, and thus would your compass heading on a globe.
      From his most recent comment: "It absolutely requires control input to prevent flying in a circle around the pole." Now I don't have a pilot's license, but ... what?

    • @flatearthbanjo
      @flatearthbanjo 4 роки тому +1

      @@okreylos This is because we fly over a flat, non-rotating Earth. Large bodies of water always remain level. The spin of the Earth has never been recorded or proven. Actually all the experiments showed that the Earth doesn't move. Gravity in definition really means Weight/Heaviness. It's the weight of an item that will keep it down, not an external force.

    • @okreylos
      @okreylos  4 роки тому +2

      @@flatearthbanjo Oh hi, I just saw a video you made about long-distance flight emergency landings and how those somehow disprove the globe. In that video, you attempt to draw a great circle route on a physical globe, but you completely fail at doing so. The route you drew is not even close to the real great circle route.
      The important thing to distinguish a great circle is this: when you look at it from straight above, the circle looks like a straight line. As it does in this video, once I rotate the globe so that the route is directly underneath the camera. Any curve on a globe that, when viewed from straight above, does not look like a straight line is not a great circle.
      More specifically, by "view from straight above," I mean that your eye, some point on the curve, and the center of the globe all need to be in a line.