Author Topic: Flat Earth  (Read 2017 times)

Offline nweber

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Re: Flat Earth
« Reply #15 on: August 02, 2018, 11:43:36 AM »
The reason for this is that map distortions caused by the requirements of FE stories (sorry, they don't rate the term "theories") are much smaller in the northern hemisphere and much larger in the southern hemisphere.

For those who haven't been keeping up to date on this particular scientific "innovation", why is that?  Is the idea that the earth is a disc, with the north pole at the centre, and the southern hemisphere spread around the outside edge?

Offline Grashtel

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Re: Flat Earth
« Reply #16 on: August 02, 2018, 04:50:03 PM »
The reason for this is that map distortions caused by the requirements of FE stories (sorry, they don't rate the term "theories") are much smaller in the northern hemisphere and much larger in the southern hemisphere.

For those who haven't been keeping up to date on this particular scientific "innovation", why is that?  Is the idea that the earth is a disc, with the north pole at the centre, and the southern hemisphere spread around the outside edge?

That is the usual version of it anyway, there are sometimes others but the disk centered on the north pole with a wall of ice around the edge is the most common
"Any technology, no matter how primitive, is magic to those who don't understand it." -Florence Ambrose

Offline ka9q

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Re: Flat Earth
« Reply #17 on: August 02, 2018, 08:53:04 PM »
My major retirement project has been education -- mentoring students at a local high school and more recently at UCSD. I think a lot about simple experiments to demonstrate basic principles of physics. For example, you can connect a resistor to a sensitive radio receiver, dunk the resistor into liquid nitrogen and have the students hear for themselves the sudden drop in noise level. It's hard to think of a more vivid demonstration of thermally vibrating molecules.

We fly high altitude balloons with cameras, and I'm always having to caution the students that they are not seeing the curvature of the earth. This usually becomes obvious enough when the camera swings back and forth and the horizon goes from being convex to concave. It's just an artifact of the camera lens.

But there is a way we might actually do it and even come up with a reasonable estimate of the earth's size. I read an airline pilot saying that he often sees other planes above the apparent horizon even when he knows them to be at lower altitudes than his own. The reason, of course, is that his sight line to the horizon is not perpendicular to his local vertical; it's lowered because of the earth's finite size.

This suggests a way to demonstrate and even measure the curvature of the earth from a high altitude balloon: mount two cameras looking horizontally exactly 180 degrees apart, then show that the actual angle between the horizon lines in opposite directions isn't 180 degrees. If you can calibrate the cameras and lenses, it should be possible (by counting pixels in the images) to measure the actual angle, and from that and your known altitude, estimate the diameter of the earth. I'll have to work on this one...

I've also been thinking of demonstrating that gravity decreases with altitude according to Newton's inverse square gravity formula. The problem is that the decrease at altitude is only about 1%, roughly the limit of what you can measure with those cheap and ubiquitous MEMS accelerometers, and they are probably also affected by temperature variations. But if I can figure out how to do it accurately, we could again estimate the diameter of the earth from the measured gravity reduction and the known altitude of the measurement.


Offline Peter B

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Re: Flat Earth
« Reply #18 on: August 03, 2018, 01:48:30 AM »
thanks a lot guys for all of that. he has actually blocked me on FB now lol

Ah well, you can't beat that sort of evidence for a flat earth, no sir.  ::)

Offline Peter B

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Re: Flat Earth
« Reply #19 on: August 03, 2018, 02:03:35 AM »
The reason for this is that map distortions caused by the requirements of FE stories (sorry, they don't rate the term "theories") are much smaller in the northern hemisphere and much larger in the southern hemisphere.

For those who haven't been keeping up to date on this particular scientific "innovation", why is that?  Is the idea that the earth is a disc, with the north pole at the centre, and the southern hemisphere spread around the outside edge?

Haven't been keeping up? Oh, you don't know what you've been missing out on!

But yes, you've described it accurately. Think of the appearance of the Earth on the UN flag, or google images of "flat earth map".

Interestingly, there are two versions of FE maps. One is the map described above, which causes the distance measuring problems I described in one of my early replies. But there's another, less common, version in which the shapes of the continents roughly match what you seen in Mercator projection maps, but which requires some subtle (and not-so-subtle) adjustments where continents meet - so the Red Sea changes from a long thin sea to a triangular shape, and Indonesia spreads out absurdly to provide a connection between Asia and Australia. (http://podcastinghandbook.co/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world-valid-flat-world-map-copy-amazon-flat-earth-map-gleason-s-new-2/)

Offline Al Johnston

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Re: Flat Earth
« Reply #20 on: August 03, 2018, 04:02:04 AM »
Actual quote from one Facebook flat-earther:

"What makes you think there is an edge?"
"Cheer up!" they said. "It could be worse!" they said.
So I did.
And it was.

Offline nweber

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Re: Flat Earth
« Reply #21 on: August 03, 2018, 09:35:35 AM »
Haven't been keeping up? Oh, you don't know what you've been missing out on!

But yes, you've described it accurately. Think of the appearance of the Earth on the UN flag, or google images of "flat earth map".

Interestingly, there are two versions of FE maps. One is the map described above, which causes the distance measuring problems I described in one of my early replies. But there's another, less common, version in which the shapes of the continents roughly match what you seen in Mercator projection maps, but which requires some subtle (and not-so-subtle) adjustments where continents meet - so the Red Sea changes from a long thin sea to a triangular shape, and Indonesia spreads out absurdly to provide a connection between Asia and Australia. (http://podcastinghandbook.co/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world-valid-flat-world-map-copy-amazon-flat-earth-map-gleason-s-new-2/)

It's not exactly my line of work, but I'm thinking I might start a theory that the earth has a spherical surface (let's not worry about pear-shaped, this is good enough for government), but the atmosphere, the sun, moon, planets, and stars (and us as well) are on the inside, and the dirt and rock and all that stuff are on the outside.

Seems to me that should be a lot more accurate.  As long as you stay near the surface, all the measurements should be accurate to a first order approximation, they'll just have the sign flipped (well, some of them) on the second order term.  If you move away from the surface, though, it will get gnarly.

Offline molesworth

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Re: Flat Earth
« Reply #22 on: August 03, 2018, 01:09:20 PM »
Interestingly, there are two versions of FE maps. One is the map described above, which causes the distance measuring problems I described in one of my early replies. But there's another, less common, version in which the shapes of the continents roughly match what you seen in Mercator projection maps, but which requires some subtle (and not-so-subtle) adjustments where continents meet - so the Red Sea changes from a long thin sea to a triangular shape, and Indonesia spreads out absurdly to provide a connection between Asia and Australia. (http://podcastinghandbook.co/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world/large-flat-world-map-new-flat-earth-map-gleason-s-new-standard-map-the-world-valid-flat-world-map-copy-amazon-flat-earth-map-gleason-s-new-2/)
It might give somewhat better measurements within continents, but it still gives wildly inaccurate distances between them.  For example, the Cook voyages mentioned previously by Peter B still need ridiculous speeds to cover the distances in the times logged.  (Or are all reports of southern hemisphere voyages faked?)

[ BTW, I can't remember if I mentioned it here, or on another forum, but I'm sailing Cape Horn to Cape Town next year and plan to take some early navigation instruments with me, to try them in the far south.  I'll also be keeping a log of progress as we go.  I'm pretty sure my measurements will be consistent with a round earth  ;)]
Days spent at sea are not deducted from one's allotted span - Phoenician proverb

Offline twik

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Re: Flat Earth
« Reply #23 on: August 03, 2018, 03:22:37 PM »
Actual quote from one Facebook flat-earther:

"What makes you think there is an edge?"

So do they think the earth goes on forever? Or do they hypothesize that maybe the "edges" meet up at some point?

Oh, wait. That would be a globe.

Offline twik

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Re: Flat Earth
« Reply #24 on: August 03, 2018, 03:25:38 PM »
As others have noted taking a picture from 6' above ground level, one would NEVER see any curvature of the Earth.  I'd have to do the math, but maybe 50 miles would give you enough coverage to discern curvature, perhaps lower.  One can't even see curvature from airplanes flying +/-40000 feet (~7 miles).  So all those negative responses won't prove the Earth isn't roughly a sphere.

I believe there are pictures taken on the beach on the US side of Lake Ontario towards Toronto that pick up the tops of buildings such as the CN Tower, but not lower building (such as the Rogers Centre beside it).

Offline bknight

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Re: Flat Earth
« Reply #25 on: August 03, 2018, 10:27:43 PM »
As others have noted taking a picture from 6' above ground level, one would NEVER see any curvature of the Earth.  I'd have to do the math, but maybe 50 miles would give you enough coverage to discern curvature, perhaps lower.  One can't even see curvature from airplanes flying +/-40000 feet (~7 miles).  So all those negative responses won't prove the Earth isn't roughly a sphere.

I believe there are pictures taken on the beach on the US side of Lake Ontario towards Toronto that pick up the tops of buildings such as the CN Tower, but not lower building (such as the Rogers Centre beside it).

Oh I truly believe that to be the case, but what I was referring is the curvature along the horizon won't show curvature
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Offline Peter B

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Re: Flat Earth
« Reply #26 on: August 03, 2018, 11:59:34 PM »
It's not exactly my line of work, but I'm thinking I might start a theory that the earth has a spherical surface (let's not worry about pear-shaped, this is good enough for government), but the atmosphere, the sun, moon, planets, and stars (and us as well) are on the inside, and the dirt and rock and all that stuff are on the outside.

Seems to me that should be a lot more accurate.  As long as you stay near the surface, all the measurements should be accurate to a first order approximation, they'll just have the sign flipped (well, some of them) on the second order term.  If you move away from the surface, though, it will get gnarly.

Well, you can present that idea if you like, and of course you can claim it as your own. But you might like to know it isn't original: I remember a conspiracy theory book from the 1970s claiming that Hitler believed that one. It is, after all, a variant of Hollow Earth.

Offline Peter B

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Re: Flat Earth
« Reply #27 on: August 04, 2018, 12:01:46 AM »
As others have noted taking a picture from 6' above ground level, one would NEVER see any curvature of the Earth.  I'd have to do the math, but maybe 50 miles would give you enough coverage to discern curvature, perhaps lower.  One can't even see curvature from airplanes flying +/-40000 feet (~7 miles).  So all those negative responses won't prove the Earth isn't roughly a sphere.

I believe there are pictures taken on the beach on the US side of Lake Ontario towards Toronto that pick up the tops of buildings such as the CN Tower, but not lower building (such as the Rogers Centre beside it).

Oh I truly believe that to be the case, but what I was referring is the curvature along the horizon won't show curvature

My concern with any plans to test FE stories at human heights is that atmospheric effects close to the ground can ruin what you're trying to achieve.

Offline nweber

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Re: Flat Earth
« Reply #28 on: August 04, 2018, 01:39:06 AM »
My concern with any plans to test FE stories at human heights is that atmospheric effects close to the ground can ruin what you're trying to achieve.

I've had the bizarre experience of looking at MalĂ© from a distance, which appeared to be a city floating on top of the ocean.  However, I'm not quite ready to claim this as evidence for the earth's curvature yet, for the reason you cite (and maybe other reasons, I haven't thought about it too hard).

Offline nweber

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Re: Flat Earth
« Reply #29 on: August 04, 2018, 02:54:49 AM »
Well, you can present that idea if you like, and of course you can claim it as your own. But you might like to know it isn't original: I remember a conspiracy theory book from the 1970s claiming that Hitler believed that one. It is, after all, a variant of Hollow Earth.

All the good ones are taken :(