Who among the old greek philosophers was the first to propose perfect circular motion for celestial objects?

Answer 1

Answer

I'm pretty sure it was not Russians. In fact it was lately Magellan, before him there were Alexandrian astronomer Ptolemy (2nd cent. AD), Gaius or Caius Plinius Secundus (23 AD), Strabo (borderline BC to AD) and Greek scholar Eratosthenes of Cyrene (267 BC), Homer in his Odyssey has known the fact of the Round World (8th century BC). So, I'd say Greek maritime knew it around 8-9 centuries before Christ (in Europe) since they had nice fleet and could travel around the Earth. In Northern Europe Vikings knew long before but were not documenting it properly, so it only formed in a way of the tales.
If you look at the Chinese, these folks knew the concept around 5th century BC, Zeng Shen (505 BC- 436 BC).
Arabs calculated the circumference of the Planet around 8th cent. AD.
India: Aryabhata (4-5c AD)

Answer

I'm not really sure, but I do think that the first time the whole world really became aware of the earth's spherical nature was when the Russians put the first artificial satellite into orbit in 1957, it was called Sputnik.


Answer(3)
The world was first 'proven' to be spherical by Ferdinand Magellan - he was the first man to sail around the world (actually he was killed en route but his crew continued the voyage and he was rightly credited). A lot of people answer Columbus to this type of question but by his time it was well known the world wasn't flat!

Answer 2

The ancient Greeks already knew that the Earth was spherical, and had figured out its size pretty closely before Rome.

In fact, Aristarchus not only knew that the Earth was round, but that the Earth orbited the Sun, 1800 years before Copernicus came up with the same theory.

Answer 3

Pythagoras in the sixth Century BC. Although it cannot conclusively be proved it was him, by the 5th century BC in the Pythagorean schools of teaching no greek writer or teacher thought the earth was anything but round.

Answer 4

Aristarchus of Samos is the earliest person known to have written that the Earth goes around the Sun. Unfortunately, Aristotle argued that based on the clear and obvious evidence of our own eyes that the Earth was still and the Sun moved.

Aristotle was wrong in this, as in so many things. In fact, Aristotle may be the wrong-est man to ever disgrace a history book.

Answer 5

The Greeks knew it, and even measured the size. It may have been known even before then.

Answer 6

Pythagoras is the first to officially propose that the earth was round, however the idea of a round earth was ambiguously referred to even before Pythagoras' time

Answer 7

Aristotle around 330 BC

Answer 8

Plato

Answer 9

Ptolmey

Answer 10

Pythagoras