The wise have known this world for a long time.

Certainly not prior to Columbus’s voyage around the world. The Greek mathematician Pythagoras was the first to suggest that the earth should be spherical. Later, the Greek philosopher Aristotle gave practical reasons why the earth should be spherical. Aristotle realized during the eclipse that the earth was situated between the moon and the sun and that the earth always casts a circular shadow on the moon during eclipses. According to Aristotle, if the earth were a large circle, as many claim, it would be straight only when the sun was directly overhead, and it would be elongated when it was tilted.

In any case, Aristotle contended that since each lunar overshadowing, the world’s shadow was dependably round, the circle was round, and that regardless of what point the sun radiated on it, the world’s shadow should be round. Additionally, Aristotle noticed that the orbits of stars varied across the globe. Aristotle came to the conclusion that the earth is not just a circle but also a sphere on the basis of these two factors. In fact, he was entirely correct in his ideas. We can see that the stars are moving in a straight line from east to west when we look at them near the equator, while in the polar regions, we can see that the stars are moving in a circle.

Eratosthenes, another Greek mathematician, demonstrated that the earth is spherical. He was an astronomer and was as versatile as Leonardo da Vinci. Math, philosophy, and geography are also among his specialties. He not only demonstrated that the earth was round, but he was also able to measure its circumference with sticks and the sun’s shadow. Arotos Thanes needed to know the size of the earth first because he was so eager to make a world map.

He lives near the Nile in Alexandria, Egypt now. He saw a well in Syene, and at noon, the sun’s shadow hit the well. Outside, there was no shadow. As a result, when he went back to Alexandria, his hometown, he carried out an experiment similar to the one at the well. He looked at the stick’s shadow after placing a stick on the ground. When the sun set on a Sydney well at noon, the stick’s shadow in Alexandria, his hometown, was slightly to the north.

At the point when the edge of the arising shadow and the finish of the stick were pulled by the rope, the highest point of the subsequent triangle was 7.2 degrees. The fact that Alexandria is north of the equator and north of the Earth is the cause of this shadow. The well no longer casts a shadow over Saigon, which is close to the equator. However, in retrospect, this is not the case. This is due to the fact that merely thinking people will quickly conclude that the shadow is emanating from the side of the sun rather than the center. However, the issue is more complex than that.

due to the fact that the sun is numerous times larger than the earth. Regardless of whether the sun were believed to be more modest than the earth around then because of an absence of information, its size would in any case be very enormous, and its light would clearly fall straightforwardly on the earth. The tilt of the light source’s path is necessary for a shadow to form. The light-receiving card must be tilted otherwise. As a result, the only thing remaining is the tilt that accepts the light now that the light source is not tilted.

The tilt of the earth’s surface at this point resembles that of a plate that receives light. Due to the fact that the shadow does not emerge on either side of the well in Saigon, it is essential to note that the world is not tilted at this point. However, the earth is tilted to the north and the shadow is moving north in Alexandria, which is further from the equator than Ceylon. So, what is taking place as the world shifts? Therefore, the earth’s surface is unquestionably curved. One possibility is that both the ground and the stick were slanted. Be that as it may, mathematicians are not genuinely awful. He believed that the scales and water scales were accurate because they had been around since ancient times.

Permit me to explain how he came up with the concept. The distance between the cities of Saigon, which has no shadow well, and Alexandria, which has a shady cane, is currently 5,000 stadia. 5000stadia is 800 kilometers, or 497 miles, away. Stadia is a ancient Greek measurement. The triangle now extends from the shadow to the rod at an upper right angle of 7.2 degrees. 7.2 degrees is one-fifth of a circle because you need to be 360 degrees to be a circle.

As a result, the 800 kilometers that separate the two cities would automatically be equal to one fifth of the total circumference. We now need 50 800-kilometer circles to complete the circle. To be precise. 50 times 7.2 degrees equals 360 degrees, which is the circumference of a circle. Therefore, you now need to combine 50 of the 7.2-degree circles to create a 360-degree circle. Add 50 of these 7.2-degree circles together and we have a full circle with an 800-kilometer circumference. Since 50 times 80 kilometers equals 40,000 kilometers, his total circumference is 40,000 kilometers (the first image below will help you understand this better).

This straightforward calculation yielded an extremely close result. Today, the circuit of the Earth is estimated around the equator at 4,075 km, and the periphery of the Earth is estimated at 4,008 km at the two posts. As a result, Arthur Tennys’ theory of measurement was extremely technologically advanced and absolutely accurate, as he was able to calculate the most precise results at the time.

As a result, when it comes to measuring the triangle’s vertex, I believe he is slightly off. When measuring angles, degrees are known to be the unit of measurement. At a single degree, this degree equals 60 minutes, and each minute equals 60 seconds. Therefore, if he had missed one second when measuring the angle at 3,600 degrees one degree, he would have missed more than 11 kilometers around the globe, and he has missed more than 70 kilometers at a rate of 6 seconds.

Even though six seconds is only one-sixth of 600 degrees, it can cause miles of misalignment when measuring the circumference of an enormous object like the Earth. However, careful measurements of “7 degrees, 12 minutes” (7.2 °) were obtained even in his day, when measurements were accurate to the minute and degree. Its triangular measurements would be off by about half to one tenth of a degree if they were off by six seconds. Even a two-second mishap can travel thousands of miles across the globe. In this manner, with the exception of only six seconds, which is 100th 100th of a 600th of a degree estimation, the exactness of the World’s perimeter was just 74 kilometers (45 miles), which is staggeringly precise in his day. It’s incredible.