| json_metadata | "{"app":"Musing","appTags":["earth","imagination","fun","thinking",""],"appCategory":"earth","appTitle":"Why Earth shape is in circle ? Have you Imagine if it was square?","appBody":"<p>I am going to take your question seriously and assume that your doubt is true. I give you a solid, experimental argument that you can prove yourself by knowing a bit of basic trigonometry. You must have the availability of traveling by road in a well-connected area (I do not know what country you are in) and be able to measure the exact distance on which you are going to travel in a straight line. You must also get two stakes or sticks 1 m high. Look at the following figure that represents two different places called P and Q distant a distance d, each located in a zone as flat as possible; there you will place the sticks vertically, one at each point:</p>\n<p><br></p>\n<p><img src=\"https://qph.fs.quoracdn.net/main-qimg-39bcdc8ba0516fef7a27c56db75e47fa\" /></p>\n<p><br></p>\n<p><br></p>\n<p>Situate yourself first at point P, during the day, when there is sun and at a time when you can observe that the sun is exactly at the zenith, that is, when the vertical stick does not project any shadow, let's assume that this happens at 12:05 noon. You will travel the distance d; the next day you place yourself at point Q, during the day and at exactly the same time 12:05 as the day before. Now, if the Earth were flat, due to the enormous distance between this planet and the Sun (1.482 * 10 ^ 8 km) at point Q, the stake would not project shade either because the sun's rays arrive parallel to the Earth flat to the Earth. same time, as illustrated in the figure above, okay?</p>\n<p><br></p>\n<p>No, what you will observe is that the stake at point Q, SI projects a shadow at the same time, which is represented by the dotted line on its left (Fig. Below), whose length is proportional to the distance traveled d The greater this distance, the greater the projected shadow. This can only occur in a round Earth or what is the same, not flat, but have some curvature as shown in the following figure.</p>\n<p><br></p>\n<p><br></p>\n<p><img src=\"https://qph.fs.quoracdn.net/main-qimg-41927451ddcaab6d88a333c8a5da788b\" /></p>\n<p><br></p>\n<p>Obviously the figure has nothing to scale, because the dimensions are exaggerated to understand the practical scheme. Point C is the center of the Earth, Z is a vertical axis that passes through points Q and C, S1 and S2 represent parallel solar rays that affect the area. This simple figure also allows us to deduce approximately the radius of the Earth:</p>\n<p><br></p>\n<p>By trigonometry, the angles defined by the segments [ZQ-QS1] = (ZQS1) and [QC-CP] = (QCP) are equal, in addition QC = CP = R, the radius of the Earth. Since the arc of the sector of the circle defined by QCP is precisely d, the distance which is assumed to be measured, then using the following elementary formula we can clear R:</p>\n<p>The QCP angle can not be measured, but the angle ZQS1, if. The more accurate these measurements are, the better the approximation for R; the same will happen the greater the distance traveled d. The interesting thing is that this simple reasoning was also made by the Greek geographer Eratosthenes (276-194 BC), with the following data: he knew the distance between Alexandria and Siena (794 km), he estimated the angle ZQS1 = 7.2 degrees = 0.1256 radians, from which he deduced that the radius of the spherical Earth must be approximately 6321 kilometers. The average radius measured today is 6371 km !!, that is, the calculation of the great Eratosthenes only had an error of 50 km, less than 0.8%!</p>\n<p><br></p>\n<p>If your interest and doubt about the roundness of the Earth is sincere, I invite you to do this experiment and convince yourself that the Earth is not flat, as some unconditional traders affirm. Another variant is the following: if you have friends in another country or in another state far from yours, ask them to measure the shadow at point Q and inform you by telephone about the angle at which the shadow is projected when its point P is at the zenith. By knowing the distance d that separates them, you will get an excellent approximation of the radius of the Earth R. Its average curvature is simply 1 / R.</p>\n<p><br></p>\n<p><img src=\"https://qph.fs.quoracdn.net/main-qimg-41927451ddcaab6d88a333c8a5da788b\" /></p>\n<p><br></p>\n<p>If you do not want to measure the roundness of the earth but only know if the earth is round, you can call a friend who is in another country, in another time zone, and ask what time it is. Do it several hours a day. If it is day and night, or if it is getting dark and he is still in the light of day, if he is at dawn and it is already in the day, what other explanation seems reasonable?</p>\n<p><br></p>\n<p>In conclusion neither is flat nor is it round: it is a spheroid.</p>\n<p><br></p>\n<p><img src=\"http://www.abroadintheyard.com/wp-content/uploads/Oblate-Spheroid.png\" /></p>\n<p><br></p>\n<p>I know this because for thousands of years it is a known fact based on trigonometry, magnetism, geometry, optics, physics, geodesy, topography, photography, cartography, astronomy ... All this leads us to think that it is a ball without any doubt.</p>\n<p><br></p>\n<p>And against it there are only conspiracy theories that are based on the hypothetical complicity of governments, scientists, military and technicians around the world for centuries to maintain a supposed lie to deceive us all with no one knows what objective.</p>\n<p><br></p>\n<p>Between what anyone can prove and a historical world conspiracy, I'm left with the first. Although the second is more exciting.</p>\n<p><br></p>\n<p>If you do not believe in any of the tests, you could make a call to a shipping company that has routes South Africa-Australia and Japan-USA. to ask them how much fuel they spend, or even to enlist in one of the boats and check it in person. Both routes cover approximately six meridians, but if the Earth were like that, the trips on the southern parallels would be twice or three times longer than the parallels of the North:</p>\n<p><br></p>\n<p><br></p>\n<p>Or even easier: take one of the commercial flights between South America and Australia that fly over the Antarctic zone:</p>","appDepth":2,"appParentPermlink":"p3x995y9x","appParentAuthor":"jaineel","musingAppId":"aU2p3C3a8N","musingAppVersion":"1.1","musingPostType":"answer"}" |
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