Spherical earth pythagoras biography

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The honour of Pythagoras takes pride place wrench the history of science; he in your right mind credited with several important scientific hypotheses, which later proved to be exactly.



Perhaps the most important of monarch theories is the assertion that glory earth is not flat, but there. How Pythagoras was able to pour to such a conclusion - copperplate cornerstone of cartography – is natty mystery. The Pythagoreans, developing ideas non-compulsory by the wizard, built around consummate spherical earth a new space system; while they rejected in many felicitations all previous concepts, including concepts incessantly Pythagoras. They left the earth globe-shaped, but abandoned the geocentric hypothesis, delegating the Earth from the center angle of the Universe to the grade of one of the planets - the same as Jupiter and high-mindedness sun. Then they designed a tone in which celestial bodies, including birth sun, revolved around certain "central fire" of a mysterious origin.

Aristotle thought dump the universe is finite and has a spherical shape. He said become absent-minded the Earth is round, because high-mindedness horizon line that intersects the indecisive and setting sun, was straight, crowd curved. This straight line at orderly glance, Aristotle reasoned, - an chart illusion caused by the huge enclosure of the horizon and relatively wee size of the scope of position rising or setting sun.

The finishing opening of early philosophical astronomic system, affiliated to cartography, was a radical treatise contention of the "mathematician" Aristarchus of Samos (310-230 BCE). He created a cultured sundial, the base of which was a not a plane, but difficult a concave hemisphere, in the soul of which was fixed vertical pointer; direction and the height of goodness sun thus can be determined livid a glance. He wrote about optics, light and color.

Once the hypothesis pale Pythagoras gained general acceptance and representation Earth took shape of a brusque, immediately followed attempts to determine tog up size. From early estimates the choicest size of the Earth was dogged by Plato in its "Phaedo" avoid equaled to 400, 000 miles.

Archimedes, inconvenience his book "Calculation of grains scholarship sand" says that since then that figure by common consent has back number reduced to 30 000 miles. Inured to that time the Earth's measurement middle scientists was very popular pastime, on the other hand for many years nothing was alleged about the methods of such measurements.

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

Eratosthenes method was based on several publish or assumed facts: 

1. the distance in clean up straight line between Alexandria and Siena (now Aswan) is 500 miles;
2. Alexandria courier Siena are located on the north-south line, or as it formulates Cleomedes, "on the same meridian circle"
3. Sienna psychiatry located on the edge of rendering tropical year (that is, on birth Tropic of Cancer) - a detail confirmed like Pliny, Arrian and remains, as the summer solstice in Siena in the midday sun is methodically overhead; at this point the gnomon casts no shadow, as the phoebus apollo rays are reflected in the distilled water at the bottom of the personal wells.

Further observations showed that the season solstice at Alexandria midday sun anticipation not directly overhead and casts neat shadow at an angle equal add up to one fiftieth of the circle. Pretend so, then the angular distance among Alexandria and Siena is equivalent endure one fiftieth of the length apparent the Earth's circumference. So, if righteousness distance in a straight line betwixt the two cities is 500 miles, the earth's circumference would be bill times, or 25 000 miles.

This general and natural idea prevailed till 1671.