Total area of Earth

Quote from: origamiscienceguy on September 11, 2016, 09:06:04 PM

I'm saying that cartographers have measured the area of the earth.

Who?  When? How?

  You know that there is quite large world out there, outside your close surroundings. Because you haven't measured anything or calculated anything doesn't mean that people before you, some even 300 years back haven't done so. And its documented. For example:
https://www.geospatialworld.net/article/the-great-trigonometrical-survey-of-india/
https://www.fig.net/resources/proceedings/fig_proceedings/cairo/papers/wshs_03/wshs03_02_zakiewich.pdf
http://www.icahistcarto.org/PDF/Smith_JR_-_The_Backbone_of_Colonial_Mapping_in_Eastern_Africa.pdf
https://books.google.com/books?id=LF_FBgAAQBAJ - Mapping an Empire: The Geographical Construction of British India, 1765-1843
http://www.eurogeographics.org/content/about-sga - About Struve geodetic arc

 I remember that there was map about how world was covered at the end of 19th century with geodetic arc. I try to find it later. You can deny all this worldwide measurements all you want but its documented, its measured/calculated and its real.

So you can't cite a single example of someone actually measuring the radius of the earth or their method, but believe it anyway. Interesting.

So you can't cite a single example of someone actually measuring the radius of the earth or their method, but believe it anyway. Interesting.

Whats wrong with that? Can you point out errors in Al Birunis method? There is quite good explanation and formulas for Al Biruni at http://www.jscimath.org/uploads/J2011172AG.pdf . If you can cast sufficient doubt in his method and point out mistakes then there is reason not to believe it. If not then I don't see a reason not to believe it. You believe flat earth without any measurements or facts. No one has seen flat earth entirely or measured anything about it but you still believe. Isn't that kind of hypocritical.

I'm not the one presenting blind assertions as irrefutable fact, so no, I don't find that hypocritical. I don't know the area of the earth. Neither do you. You have a belief derived from belief in authority. 

And Al-Biruni assumes a globe and calculates a radius. If I start with a bunch of assumptions,  I could calculate the area of the earth in a plane or a doughnut, too. Hypothetical maths lead us no closer to actual knowledge.

Well, we know the earth is a globe, so that's not an assumption.

I'm not the one presenting blind assertions as irrefutable fact, so no, I don't find that hypocritical. I don't know the area of the earth. Neither do you. You have a belief derived from belief in authority. 

And Al-Biruni assumes a globe and calculates a radius. If I start with a bunch of assumptions,  I could calculate the area of the earth in a plane or a doughnut, too. Hypothetical maths lead us no closer to actual knowledge.

  Al Biruni did not assume a globe. He had previous evidence that the earth is globe and calculated raidus. You really should not assert your ignorance to the others. And you clearly present blind assertions as irrefutable fact. That is - earth is flat. No one has show it yet. You neither.
 But anyway, as I can't cite a single example of someone actually measuring the radius of the earth you also can't cite a single example where anyone has done such experiment and got totally different results or proven it wrong. And you still believe that its false/fake/wrong/whatever. Intresting.

Quote from: Ski on September 13, 2016, 12:15:08 PM

I'm not the one presenting blind assertions as irrefutable fact, so no, I don't find that hypocritical. I don't know the area of the earth. Neither do you. You have a belief derived from belief in authority. 

And Al-Biruni assumes a globe and calculates a radius. If I start with a bunch of assumptions,  I could calculate the area of the earth in a plane or a doughnut, too. Hypothetical maths lead us no closer to actual knowledge.

  Al Biruni did not assume a globe. He had previous evidence that the earth is globe and calculated raidus. You really should not assert your ignorance to the others. And you clearly present blind assertions as irrefutable fact. That is - earth is flat. No one has show it yet. You neither.
 But anyway, as I can't cite a single example of someone actually measuring the radius of the earth you also can't cite a single example where anyone has done such experiment and got totally different results or proven it wrong. And you still believe that its false/fake/wrong/whatever. Intresting.

I do apologise for the length, but Ski seeme to demand chapter and verse, but don't worry there is a lot more available.

Al Biruni measured the size of the earth by a number of means, one the earliest was similar to Erostosthanes' method but he also measured the radius by measuring the dip angle to the horizon as in Al-Biruni's Classic Experiment: How to Calculate the Radius of the Earth? The following is from this reference.

Abbasid Caliph Al-Mamun thus employed a team of renowned scholars of that time and assigned them the task of calculating the size of the earth. They started by finding the distance over which the sun's angle at noon changed by 1 degree, multiply it by 360 and you arrive at the circumference from which size can be deduced. They arrived at a value which was within 4% of the actual value. The problem with this method was that it was cumbersome to measure large straight line distances between two points in the heat of the desert and perhaps they only had to count paces to measure it. Al-Biruni devised a more sophisticated and reliable method to achieve this objective. To carry out his method Biruni only needed three things. An astrolabe. A suitable mountain with a flat horizon in front of it so that angle of depression of horizon could be accurately measured. Knowledge of trigonometry. The first step: Calculation of the height of a mountain requires three measurements. Angle of elevation of the mountain top at two different points lying on a straight line were measured using an astrolabe. Biruni probably had a much larger astrolabe then that illustrated on the right to ensure maximum accuracy close to two decimal places of a degree. The third being the distance between these two points was perhaps found using paces. These values were then computed with simple trigonometric techniques to find the height as shown in the figure above. This is a relatively simple and easy to understand problem, I even used to solve these types of problem back in school! Biruni used the following formula. For the purpose of simplicity lengthy derivation is omitted.

The Astrolabe

Method of determining height

The second step: was to find the angle of dip or angle of depression of the flat horizon from the mountain top using the astrolabe in the same way, this being the fourth measurement. It can be further seen from the diagram that his line of sight from the mountain top to the horizon will make an angle of 90° with the radius.

And finally we come to the useful bit, the ingenuity of this method lies in how Biruni figured out that that the figure linking the earth’s center C, the mountaintop B, and the (sea or flat enough) horizon S was a huge right triangle on which the law of sines could be made to yield the earth’s radius!

Calculating radius of the Earth.

Now we can apply the law of sines to this triangle to find R.

So Exactly how accurate was Biruni ?

With his formula Biruni arrived at the value of the circumference of the earth within 200 miles of the actual value of 24,902 miles, that is less then 1% of error. Biruni's stated radius of 6336 km is also very close to the original value.

There are available more detailed writings analysing the accuracy Al Biruni achieved, which I believe I have presented earlier.

But, I do think it fair to say that Al Biruni measured the radius of the earth and

So you can't cite a single example of someone actually measuring the radius of the earth or their method, but believe it anyway. Interesting.

Single Example.

And in there also says:
"And it went way beyond an academic debate when the French minister of the navy understood that it was
necessary to know the exact shape of Earth in order to accurately navigate the oceans.
A nation that can locate its ships at sea can control an empire."

That seems to calculating degrees of latitude assuming a globe.  I didn't see a single thing in there about measuring the radius of the earth. Odd.  It's like you continue answering questions I am not asking...

That seems to calculating degrees of latitude assuming a globe.  I didn't see a single thing in there about measuring the radius of the earth. Odd.  It's like you continue answering questions I am not asking...

But, Al Biruni did it a little differently. He measured the "dip angle to the horizon", so effectively measured the curvature.

So, I think it fair to say that Al Biruni measured the radius of the earth and

Of course any surveyor can do the same thing any time - any volunteers?

"The horizon always rises to eye-level".

Which is possible for concave or infinite plane with infinite viewing distance, but not for "small" disc with limited view.

If the view were perfect, that would allow measruing the actual size of the disc and thus total area.

Quote from: Ski on September 14, 2016, 08:44:51 PM

That seems to calculating degrees of latitude assuming a globe.  I didn't see a single thing in there about measuring the radius of the earth. Odd.  It's like you continue answering questions I am not asking...

But, Al Biruni did it a little differently. He measured the "dip angle to the horizon", so effectively measured the curvature.

I know thought you're smart enough to realize his "method" assumes the shape of the earth before "calculating" the radius.  But maybe you're not.   
Anyone else have a measurement of the earth's radius? Or are you going to post more of your faith based rationalizations for me?

I know thought you're smart enough to realize his "method" assumes the shape of the earth before "calculating" the radius.  But maybe you're not.

Anyone else have a measurement of the earth's radius? Or are you going to post more of your faith based rationalizations for me?

To find a radius of an object you first need to know what shape it is. You can't find a radius of a sphere without knowing it is a sphere.

Then how could such a calculation be an evidence of sphericity if it relies on an assumption of sphericity? 

Then how could such a calculation be an evidence of sphericity if it relies on an assumption of sphericity? 

It's not (circular argument). Who claimed that?

That seems to calculating degrees of latitude assuming a globe.  I didn't see a single thing in there about measuring the radius of the earth. Odd.  It's like you continue answering questions I am not asking...

Yes as far as I know, they measured the "length" of three degrees at the equator.
Undoubtedly they measured their degrees by taking either sun sightings, or more likely star sightings.

The length of a degree of latitude at the equator is 68.71 miless, so 3° would be 206.13 miles.

So, if the earth is flat and  (to keep calculations simple) we can calculate the sun height as  206.13/tan(3°) = 3,933 miles.

There are two things to note:
Firstly, we are told that the sun is around 3,200 miles high, and repeating the above calculation for the range 0° - 45°, you do get 3,105 miles.
Secondly, 3,933 miles looks suspicially like the radius of the globe earth - a coincidence?

So how do Flat Earthers explain the sun height of 3,933 miles when measured over 3° at the equator, but 3,105 miles measured over 0° - 45°?
Yes I know, just ignore it and hope it goes away, but it won't. That's only half the story - you try the same calculation for the range 0° - 75°.

Then how could such a calculation be an evidence of sphericity if it relies on an assumption of sphericity? 

There is no assumption of spherity. There is knowledege of spherity. Its really interesting how you assume that if you don't know something or can't do something then anyone else can't also. Why is it so?

You said you have knowledge of the area of the earth. I asked how you measured and reached the knowledge. You then all back peddled and said someone else "measured" it, and you simply believed them. Then I said the "measurement" lies on a assumption and is simply empty math, and now you're back to "knowing" the earth is a sphere... It sounds like you simply "believe" the earth is round and "believe" the radius calculations based on that assumption       sounds like "scientism" to me

Or, you knowz, I did erestoththenes experiment .

You did? When?   Also that "experiment" preassumes the shape of the earth (which we already demonstrated)

You said you have knowledge of the area of the earth. I asked how you measured and reached the knowledge. You then all back peddled and said someone else "measured" it, and you simply believed them. Then I said the "measurement" lies on a assumption and is simply empty math, and now you're back to "knowing" the earth is a sphere... It sounds like you simply "believe" the earth is round and "believe" the radius calculations based on that assumption       sounds like "scientism" to me

So, everything you believe, you have determined yourself?

You claim that the earth is flat and accelerates "upward" at 9.8 m/s².
1. How did you prove yourself that the earth is flat, without getting any information from any person?
2. How did you determine that this so-called acceleration is exactly 9.8  m/s², expecially we observe that objects fall at different rates?
3. You claim Mach''s Principle explains various observations. Have you personally proved  Mach''s Principle?

Quote from: Brouwer on September 09, 2016, 12:01:10 AM

Quote from: -leigh- on September 08, 2016, 11:58:10 PM

there isnt a total area of the earth otherwise we be falling off the edge,it goes on and on forever

Infinite plane Earth cannot phisically exist.

neither can a big spinning ball keeping water stuck to it

Don't forget the air stuck to the ball , which air is also inserted into a vacuum.

It actually can, because of gravity.

We even made a formula for it.

What is the total area of the earth?

Infinite. Or possibly finite.

Then how could such a calculation be an evidence of sphericity if it relies on an assumption of sphericity? 

Peru mission MEASURED degrees, not calculated them out of thin air.

Ski, you'll never get them to realize that theirs is just another religion as one of the tenets of their religion is that it is not one. I find it especially funny that they use funny mathematics to validate their tenets - as mathematics is one of the only branches of knowledge that can prove it has truths that must be taken without evidence. Oh boy! Somebody tell these guys about Cantor's slash.

Ski, you'll never get them to realize that theirs is just another religion as one of the tenets of their religion is that it is not one. I find it especially funny that they use funny mathematics to validate their tenets - as mathematics is one of the only branches of knowledge that can prove it has truths that must be taken without evidence. Oh boy! Somebody tell these guys about Cantor's slash.

Where is the funny maths in determining the size and shape of the earth, how have you done it?

To do such a thing as "determine through maths" - a laughable endeavor for any task -  the size of the Earth I would have to assume the shape of the earth. I can't say I know it; however it is within my worldview. Haven't you been paying attention?

I will say it certainly is the stronger of the two views though.

Also, here is the funny math you requested: http://www.theflatearthsociety.org/home/index.php/blog/infinite-flat-earth-mathematics

Ski, you'll never get them to realize that theirs is just another religion as one of the tenets of their religion is that it is not one.

Flat earth is better than this? Open-minded brainwash-free people can't event provide a single evidence for their "beliefes".

I find it especially funny that they use funny mathematics to validate their tenets - as mathematics is one of the only branches of knowledge that can prove it has truths that must be taken without evidence.

You clearly don't know what the mathematics is.

Oh boy! Somebody tell these guys about Cantor's slash.

And? What's the point of it?

Also, here is the funny math you requested: http://www.theflatearthsociety.org/home/index.php/blog/infinite-flat-earth-mathematics

An infinite earth is physically impossible. And, as some wiser than me people commented, your blog post is full of errors.