How to Measure the Earth's Radius

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  • Опубліковано 18 гру 2024

КОМЕНТАРІ • 138

  • @eonasjohn
    @eonasjohn 4 місяці тому +2

    Thank you for the video.

  • @1616katerst
    @1616katerst Рік тому +1

    Hi. Very nice fast demo of trig and this is actually how celestial navigation works. Cool man!

    • @logansrun6478
      @logansrun6478 11 місяців тому

      Not that simple pal.
      The horizon isn't a fixed location, it an apparent location due to refraction which unfortunately debunks Al-bri
      Never stop thinking when you think you know

    • @marcg1686
      @marcg1686 7 місяців тому +2

      ​@@logansrun6478The geometry Al Biruni employed was sound.
      Refraction does not debunk his method, it does degrade the quality of the result.

    • @AutodidacticRED
      @AutodidacticRED 19 днів тому

      Begging the question!

  • @phredro1731
    @phredro1731 Рік тому +7

    I once read the definition of 'level' from a surveying textbook to a flatearther. His response? "Well, they're wrong!" LOL.

    • @physicsalmanac
      @physicsalmanac  Рік тому +7

      I believe that is the standard flatearther response to everything.

    • @timetraveler7
      @timetraveler7 Рік тому +5

      Yeah that sound about right.

    • @marcg1686
      @marcg1686 7 місяців тому +1

      ​@harrywilfong2008Level means perpendicular to a vertical.

  • @MattWillEast
    @MattWillEast Рік тому +2

    @NathanOakley1980 Hope to see you on the show! Wishing you and yours well.

    • @physicsalmanac
      @physicsalmanac  Рік тому +2

      is there gonna be another one? I'll join if I can.

    • @MattWillEast
      @MattWillEast Рік тому

      @@physicsalmanac yes tomorrow morning 8am central standard time

    • @jetpond7904
      @jetpond7904 Рік тому +2

      @@physicsalmanac don’t join
      He’s going to scream at you and mute you constantly

    • @physicsalmanac
      @physicsalmanac  Рік тому +2

      Yeah I commented answering some of his (insincere) questions, and he deleted it pretty much immediately.

    • @jetpond7904
      @jetpond7904 Рік тому +3

      @@physicsalmanac I got banned from his channel because in the live chat on his livestream of an aftershow, I pretty much destroyed flat earth directly, to him live, with lunar eclipse predictions
      And then he banned me

  • @ronstiles2681
    @ronstiles2681 Рік тому +4

    Nice video sir:)

  • @mohammedal-haddad2652
    @mohammedal-haddad2652 Рік тому +1

    That was very interesting.

  • @carultch
    @carultch Рік тому +2

    How does light "know" its destination, to take the path of minimized time, per Fermat's principle?

    • @physicsalmanac
      @physicsalmanac  Рік тому +4

      Great question! It turns out that this is answered with quantum mechanics. It’s not that light actually takes the path of least time, it actually has some probability of taking any path. But it turns out that, loosely speaking, around this path the probabilities of photons arriving all line up and add together. So the intensity is greatly boosted near that trajectory. So this path dominates over all other paths.

    • @rockapedra1130
      @rockapedra1130 Рік тому +1

      I don't think you need quantum mechanics for this. You can probably show that constructive/destructive interference of classical waves gets the same result?

    • @physicsalmanac
      @physicsalmanac  Рік тому +1

      That’s true. It’s equivalent. The wave theory of light is ultimately a coarse grained model of the quantum theory of light. The math is identical but the interpretation is different.

    • @JasonCoffman-xu5ks
      @JasonCoffman-xu5ks 3 місяці тому

      Answer is that light doesn't know where it is going. Why would you even suggest that? From the source, it goes in every direction equally

  • @skivvy3565
    @skivvy3565 5 місяців тому +4

    all these people mentioning nathan oakley are making me extremely disheartened, i didn't know people actually truly believed in the flat earth thing still

    • @physicsalmanac
      @physicsalmanac  5 місяців тому +2

      You and me both man.🤦🏽‍♂️

  • @Melanatedone
    @Melanatedone Рік тому +1

    Question... If we use a super digital zoom, we could see much further than using our eyes. The zoom on the tech has a limit as well because the atmosphere well eventually show nothing but haze in the display. So how can any of this every be accurate if the horizon is limited to how far we can view?

    • @physicsalmanac
      @physicsalmanac  Рік тому +5

      The horizon is not limited by how far we can see. There is no limit to how far we can see, instead the limit is the angular size of something. We an see things much farther than the horizon, as long as they are big enough, like stars or the moon for example, which is about 240,000 miles away. The horizon is only a few miles away. The horizon is just the farthest point on earth we can see. Not because our eyes can't see farther, but because the earth is round, and curves below our feet after the horizon. Check out my video " How far is the horizon" to understand this better: ua-cam.com/video/8N8mxnjnIHI/v-deo.html
      Hope this clears things up.

    • @Melanatedone
      @Melanatedone Рік тому +1

      ​@@physicsalmanac ...Thanks for the reply and clarification. I appreciate your time.
      You stated that "The horizon is just the farthest point on earth we can see."
      If we measured it using our eyes and the description which you have given, would it not have vastly different measurements from measuring it using a digital eye, lets say a telephoto with a 1000x zoom.
      So where is the true horizon?

    • @physicsalmanac
      @physicsalmanac  Рік тому +3

      @@Melanatedone whether you use a zoom or your eye, doesn't change the horizon point. A zoom just makes objects on the horizon appear larger. The horizon is the geometric location where your line of sight just skims the earth's surface. The reason there is a horizon, is because the earth is round, and after that point the earth's surface is below our feet in a sense. The horizon is the farthest we can see on earth, not due to any limitations of the eye, but because you would have to look through the ground to see any farther along the earth's surface. That is, your line of sight would have to travel through the earth to see the other side. If the earth were flat, there would be no horizon, other than the edge of the earth.

    • @Melanatedone
      @Melanatedone Рік тому +1

      @@physicsalmanac Thank you.
      Very interesting.
      How far up given established diameter of the earth would you say we'd have to be in order to notice a dip and curving of the horizon.
      My line of question started because I recently saw conflicting views from authorities on the matter.

    • @physicsalmanac
      @physicsalmanac  Рік тому +2

      @@Melanatedone I'm not sure. I suppose it would be determined by how sensitive your eye is at interpreting straight lines.

  • @CCP-Lies
    @CCP-Lies 9 місяців тому +2

    Nowadays you can send a flat earther to the ISS, he won't be convinced earth is round

    • @JasonCoffman-xu5ks
      @JasonCoffman-xu5ks 3 місяці тому

      He will say he was tricked into believing he went there. They are all crrraasszzzzyyyy

  • @wiggles7976
    @wiggles7976 Рік тому +1

    I have done this and I have a video about it on my channel. I repeated the measurement many more times and got an average error of about 23%.

    • @physicsalmanac
      @physicsalmanac  Рік тому +1

      Nice! Shows how sensitive this experiment is. You need very precise measurements to pull it off. Especially for the dip angle to the horizon.

    • @wiggles7976
      @wiggles7976 Рік тому +2

      @@physicsalmanac Precision is definitely important. Refraction is a big thing to worry about too as it is a huge source of error. I've seen surveyor measurements with worse single measurements than 23%, or at least some huge error. I've had a single measurement being 100% off or more. Refraction basically makes the Al-Biruni measurement useless for modern Earth radius measurement. However, it's still fun as something to do that's close enough.

  • @mohdmehraj6734
    @mohdmehraj6734 Рік тому +2

    And, people miss guided others on that the Quran says about flat earth. But if it is true. So why this muslim guy calculated the radius of earth in the early islamic period. It proofs that The early muslims believed on spherical (approx) earth, not flat. And in the Quran, flat word use is based on our observation as we say sun set and sun rise. But in actually there is no sun set and rise, it is based on our observations.

    • @yesihavereadit
      @yesihavereadit 8 місяців тому +1

      By ignoring the quran

    • @mahfuzurrahmanhowlader3240
      @mahfuzurrahmanhowlader3240 17 днів тому

      ​@@yesihavereadit did he?

    • @yesihavereadit
      @yesihavereadit 17 днів тому

      @mahfuzurrahmanhowlader3240 if he said it was round, he ignored the Qu'ran. Where does the quran say its round.

    • @mahfuzurrahmanhowlader3240
      @mahfuzurrahmanhowlader3240 17 днів тому +1

      @@yesihavereadit the quran doesn't say anything about planet earth's shape

    • @yesihavereadit
      @yesihavereadit 17 днів тому

      @@mahfuzurrahmanhowlader3240 spread out, stretched, is how the earth is described

  • @oxbowspirit4378
    @oxbowspirit4378 Рік тому +3

    Nathan Oakley 1980 adressed your video. Take a look.👍

    • @physicsalmanac
      @physicsalmanac  Рік тому +1

      Thanks for heads up. I've never heard of him. Do you have a link? I went to his channel, but couldn't find which video.

    • @physicsalmanac
      @physicsalmanac  Рік тому +2

      Never mind I found it. Thanks

    • @dazstudio68
      @dazstudio68 Рік тому

      ua-cam.com/video/SmZaATTmVFc/v-deo.html
      @NathanOakley1980 made a response
      Much algorithmic love ❤

    • @marcg1686
      @marcg1686 7 місяців тому +1

      @oxbowspirit4378
      The current YT flat earth hoax is about nine years old now, yet you feckless clowns still can't calculate the distance to the flat earth horizon based on the height of the observer.
      Mere miles away and you can't do it.

  • @jamesbreeden9016
    @jamesbreeden9016 Рік тому +1

    Gatekeeping made easy by mathematics

    • @physicsalmanac
      @physicsalmanac  Рік тому +3

      Is the knowledge of mathematics forbidden to some?

    • @jamesbreeden9016
      @jamesbreeden9016 Рік тому

      @physicsalmanac When you make up or support lies with mathematics. That would be a problem, don't you think

    • @physicsalmanac
      @physicsalmanac  Рік тому +3

      Even if this were true, how is it related to gatekeeping?

    • @jamesbreeden9016
      @jamesbreeden9016 Рік тому +1

      @physicsalmanac "Even if that were true." At least you're halfway honest.

    • @betaorionis2164
      @betaorionis2164 11 місяців тому +5

      @@jamesbreeden9016I guess you were not good at maths at school and now try to cheat yourself pretending it’s the rest of the world who is wrong? How delusional.

  • @logansrun6478
    @logansrun6478 11 місяців тому

    However the horizon isn't a fixed location, it an apparent location due to refraction which unfortunately debunks Al-bri

    • @physicsalmanac
      @physicsalmanac  11 місяців тому +4

      That's true there is a small correction due to atmospheric refraction. I wouldn't say this debunks Al-Biruni... rather that it means that you can see a little bit farther than he thought. I calculated this correction in the follow up video if you're interested.

  • @ronstiles2681
    @ronstiles2681 Рік тому +8

    Sorry but how can someone get flat earth out of this, must be the magic mushrooms , wow

    • @physicsalmanac
      @physicsalmanac  Рік тому +9

      Magic mushrooms + ideology = I am the special bearer of the secret truth.

  • @kaeez
    @kaeez 8 місяців тому

    I don't know, I still feel like Eratosthenes' method is superior.

    • @marcg1686
      @marcg1686 7 місяців тому

      I agree. He had almost no refraction to contend with.

  • @rockapedra1130
    @rockapedra1130 Рік тому +1

    I knew it! The Earth *is* flat!!! (Your video was too mathy, so I didn't pay attention ...)

  • @barryon8706
    @barryon8706 Рік тому +1

    Thanks fo rproving the flat earth (...to everyone who already assumed everything proves the flat earth). And enjoy this sacrifice to the algorithm spirits. 😀

  • @RB-sz9gv
    @RB-sz9gv Рік тому

    TOTAL PSEUDOSCIENCE. Thank you for pointing this out

  • @TrippCanada
    @TrippCanada Рік тому +2

    Lol, at 1:56 you say you need a flat surface to make this calculation. 🤡

    • @physicsalmanac
      @physicsalmanac  Рік тому +7

      Flat = level in this context.

    • @TrippCanada
      @TrippCanada Рік тому +2

      @Physics Almanac bud, ur lost. Flat is is a description of level in any context 🤡. The earth is over 70% water that sits at its level hence sea level. Earth is a flat stationary horizontal plain, does not matter how many calculations you think prove otherwise.

    • @physicsalmanac
      @physicsalmanac  Рік тому +5

      @@TrippCanada A flat surface can be on an incline. In which case it is not level, i.e. a ball would roll down it.
      Calculations never prove anything. Observation/experiment does.

    • @dazstudio68
      @dazstudio68 Рік тому +1

      ​@@TrippCanada
      He meant to say " flat = curved"😂

    • @TrippCanada
      @TrippCanada Рік тому

      @Physics Almanac incline or decline maybe, curve never. The flat surface remains flat even on an incline or decline.

  • @RB-sz9gv
    @RB-sz9gv Рік тому

    Error #2: Cubit - we don’t know the measurement

  • @RB-sz9gv
    @RB-sz9gv Рік тому

    Error #3: light curves - total pseudoscience

  • @RB-sz9gv
    @RB-sz9gv Рік тому

    Error #1: you cannot measure accurately the angle of level to the top of a mountain

  • @RB-sz9gv
    @RB-sz9gv Рік тому

    Error #3: requires a flat earth for data (which is reality), but negates this method

  • @LiesExposed1
    @LiesExposed1 Рік тому +1

    Earth is not a spinning globe but a stationary enclosed horizontal sea level everywhere plane with mountains and valleys

    • @physicsalmanac
      @physicsalmanac  Рік тому +7

      Definitely. 100%.

    • @timetraveler7
      @timetraveler7 Рік тому +6

      What is it with flat earthers under these videos, don't y'all have families to disappoint?

    • @LiesExposed1
      @LiesExposed1 Рік тому +1

      @@timetraveler7 1🤡🌏🔨

    • @timetraveler7
      @timetraveler7 Рік тому +4

      @@LiesExposed1 I see words ain't your strong suit, to be fair math and science aren't either.

    • @LiesExposed1
      @LiesExposed1 Рік тому +1

      @@timetraveler7 its ok fruitcake go back to sleep FLUFFY

  • @DivergentDroid
    @DivergentDroid Рік тому +2

    Thank you for proving the Flat Earth! You are Right, you Need a flat baseline or you Cannot take the elevation angle! Great stuff! @NathanOakley1980 sent me! He reviewed this video today!

    • @physicsalmanac
      @physicsalmanac  Рік тому +5

      Flat in this case means level (not on an incline).

    • @DivergentDroid
      @DivergentDroid Рік тому +1

      @@physicsalmanac YES! That's Exactly what Flat does mean. Flat is Not a shape. Flat is an aspect or description of a surface. You probably think we Flat Earthers think Flat is a shape as in flat as a pancake. No. That's not what we mean at all. When we say Earth is Flat we are talking about the measurement of the surface, Not an overall shape of Earth. We make No claims at all as to any overall size or shape of Earth. You globe Earthers think such things about us because you are being lied to by your globe believing fellows who would rather be dishonest then discuss the truth of what we actually believe.

    • @physicsalmanac
      @physicsalmanac  Рік тому +5

      Well many self designated flat earthers do mean the earth is shaped like a pancake. Maybe you don’t. But your claim seems even more bizarre. It sounds like you’re saying the surface of the earth has no inclined areas? Like mountains don’t exist?

    • @DivergentDroid
      @DivergentDroid Рік тому

      @@physicsalmanac They promote the azimuthal equidistant north pole projection as something that might be similar to what we live on but that is all. It was never meant to be a map or model written in stone. None of us believe Earth is a flat disk floating in your 2nd law of thermodynamics Nasa calls space.

    • @El__Forastero
      @El__Forastero Рік тому +1

      @@physicsalmanac Yes, flat does = level. How perceptive of you.

  • @dazstudio68
    @dazstudio68 Рік тому +3

    Hey great video
    @NathanOakley1980 sent me
    as he has made you a response to your video
    Much algorithmic love ❤

  • @Caynewest
    @Caynewest Рік тому +3

    @NathanOakley1980 sent me.

    • @physicsalmanac
      @physicsalmanac  Рік тому +3

      Well thanks for stopping by. 🙂

    • @dazstudio68
      @dazstudio68 Рік тому

      ua-cam.com/video/SmZaATTmVFc/v-deo.html
      @NathanOakley1980 made a response
      Much algorithmic love ❤