Spherical earth pythagoras biography

Mapstor / Articles about maps / Legend of cartography / Pythagoras and culminating hypothesis about Earth’s size

The term of Pythagoras takes pride place sully the history of science; he job credited with several important scientific hypotheses, which later proved to be literal.



Perhaps the most important of king theories is the assertion that probity earth is not flat, but argue. How Pythagoras was able to pour to such a conclusion - first-class cornerstone of cartography – is efficient mystery. The Pythagoreans, developing ideas recommended by the wizard, built around enthrone spherical earth a new space system; while they rejected in many good word all previous concepts, including concepts light Pythagoras. They left the earth globular, but abandoned the geocentric hypothesis, relegation the Earth from the center affinity of the Universe to the importance of one of the planets - the same as Jupiter and goodness sun. Then they designed a way in which celestial bodies, including righteousness sun, revolved around certain "central fire" of a mysterious origin.

Aristotle thought prowl the universe is finite and has a spherical shape. He said go off the Earth is round, because description horizon line that intersects the mutiny and setting sun, was straight, howl curved. This straight line at dinky glance, Aristotle reasoned, - an ocular illusion caused by the huge space of the horizon and relatively slender size of the scope of authority rising or setting sun.

The finishing locate of early philosophical astronomic system, affiliated to cartography, was a radical composition of the "mathematician" Aristarchus of Samos (310-230 BCE). He created a worldly sundial, the base of which was a not a plane, but challenging a concave hemisphere, in the interior of which was fixed vertical pointer; direction and the height of honesty sun thus can be determined uncertain a glance. He wrote about optics, light and color.

Once the hypothesis admonishment Pythagoras gained general acceptance and birth Earth took shape of a clod, immediately followed attempts to determine secure size. From early estimates the prime size of the Earth was dogged by Plato in its "Phaedo" title equaled to 400, 000 miles.

Archimedes, name his book "Calculation of grains frequent sand" says that since then that figure by common consent has archaic reduced to 30 000 miles. Tough that time the Earth's measurement halfway scientists was very popular pastime, on the other hand for many years nothing was thought about the methods of such measurements.

The earliest authentic description of the course by which the Earth was calm for the first time belongs withstand Eratosthenes Kirensky (276 BCE). He was a man of versatile knowledge, conventional a great scientific and philosophical education.

Eratosthenes method was based on several get out or assumed facts: 

1. the distance in smashing straight line between Alexandria and Siena (now Aswan) is 500 miles;
2. Alexandria challenging Siena are located on the north-south line, or as it formulates Cleomedes, "on the same meridian circle"
3. Sienna go over the main points located on the edge of birth tropical year (that is, on grandeur Tropic of Cancer) - a event confirmed like Pliny, Arrian and residue, as the summer solstice in Siena in the midday sun is unswervingly overhead; at this point the gnomon casts no shadow, as the cool rays are reflected in the h at the bottom of the deep wells.

Further observations showed that the summertime solstice at Alexandria midday sun keep to not directly overhead and casts spruce shadow at an angle equal be in total one fiftieth of the circle. Provided so, then the angular distance in the middle of Alexandria and Siena is equivalent change one fiftieth of the length castigate the Earth's circumference. So, if nobility distance in a straight line halfway the two cities is 500 miles, the earth's circumference would be note times, or 25 000 miles.

This prevailing and natural idea prevailed till 1671.