Eratosthenes of Cyrene

Just wanted to put this out there since i found it totally awesome.

Eratosthenes of Cyrene was a Greek mathematician, elegiac poet, athlete, geographer, astronomer, and music theorist. He was the first person to use the word "geography" and invented the discipline of geography as we understand it. He invented a system of latitude and longitude. Most importantly E was the first person to calculate the circumference of the earth by using a measuring system using stades, or the length of stadiums during that time period. If you remember from basic math what circumference implies, this means he thought the earth was round... and measured it during his lifetime (276 BC – 195 BC).

How he did it

After reading a book in the Library of Alexandria he noted that in the town of Syene at noon on the summer solstice, sun would light up the bottom of a well. Being it close to the summer solstice in Alexandria he attempted to create the same event, so instead of digging a well, he placed a stick in the ground, all things being equal a stick should cast no shadow,but to his surprise a shadow indeed was created. E was no fool, he measured both the height of the stick and the shadow it created. off he went.





from the image you can see how fairly simple the math really is, angles A and B must be the same (parallel lines created by the sun). the length of the shadow gives you angle A.

At this point E needed to calculate the distance between Alexandria and Syene... So he hired a guy to pace it out. The man paced to Syene, turned around and paced back. they averaged the two distances. Once E had the distance, he could calculate the circumference of the world... he thought 25,000 miles.

Eratosthenes was off by 1%. not bad for a man who used nothing but sticks, feet and a little brain power.

Eratosthenes - proving the world round since ~ 250 BC

More on E



[edit on 26-7-2010 by monguzi]

[edit on 26-7-2010 by monguzi]



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[edit on 1/8/10 by masqua]

Nicknamed "beta" by fellow Greeks, they said he was the "second" best in history in every field he studied.

Harte

you are absolutely right Harte!

and maybe it is just me, but i always found how smart these guys were shocking... If only they hadn't burned the library.

SandF
In school they ridiculed the Greeks
because they thought the universe was composed of:
earth, air, fire, and water,...silly greeks.

mass, thought, energy, vibration.
which is how other ancient diciplines translate those symbols.
just like modern physics.

They knew a lot more then we are taught they did I think.

Originally posted by monguzi
you are absolutely right Harte!

and maybe it is just me, but i always found how smart these guys were shocking... If only they hadn't burned the library.

Seems there wasn't a lot in that library that would be "shocking," IMO.

I mean, there's plenty of other ancient libraries that survived.

Alexandria was Greek anyway, and certainly had nothing in it much older than the Greeks.

Not that the Greeks weren't impressive, mind you.

Harte

[edit on 7/26/2010 by Harte]

This is a great post

the story makes me imagine a guy who observes carefully and wants to know
that 's what motivated him ..he needed to know for his own satisfaction

that's pretty cool living in this age where everyone has an angle and something to sell

reply to post by Danbones


yeah, and to think how much knowledge we lost, and how far behind we are, than we should be. the Greeks started it all, and the closest we come to thanking them is Plato this and Aristotle that... Pythagorean Theorem. But who can tell me who invented the scientific method? I know, but i feel saddened that when my daughter came home from school, saying that she had learned the scientific method, and i asked her what she thought of Thales of Miletus. she responded "who's that?"

this is what made me think to post this... after our long lesson on who/what the Greeks were, and how little her teacher really knew. jk about her teacher. i would never tell my daughter that even though i think it.

reply to post by Harte


The way they ran the library was very different then what we think of today. whenever a ship pulled into port it was inspected for books, the books were then transcribed, and copies given back to the owners... that's right they kept the originals. at its hight the Library of Alexandria had at best guess close to a million books. Alexander the Great set it up this way, to acquire knowledge from whoever traded with his empire and store it all in Alexandria.

now, we have all heard "dont put all your eggs in one basket". so, here is their fault.

[edit on 26-7-2010 by monguzi]

Ah, Monguzi -- what a fun read! You DO know your history! I hated it when it was dates, but loved it when it started to get into personalities. The Roman Emperors were endlessly fascinating, as were the Greek scientists.

They no longer study the classics in school, and I think it's a bit of a loss. I remember reading Edith Hamilton's book on the Romans and bugging the librarians till they came up with a copy of her book on the Greeks. Amazing woman: en.wikipedia.org...

Your post inspired me to go look up a bit more on Eratosthenes. What an amazing man he was. I'd have loved to go hang out with him for a year or two.

One of the great myths of the alternative world is that great masses of 'secret' or 'hidden' knowledge was lost with the series of destructive incidents that effected the libraries now collectively known as the 'Library of Alexandria'.

Now secret in library

The libraries (there were actually three which became known as the Great Library) suffered numerous fires etc but in general was open for 3-4 centuries. With what we can determine was 'open' access to Greek and later Roman scholars. Comments by these authors were known and commented on by other authors.

Strangely nothing too weird or strange was noted and the Roman's in particular were into oddities as noted in many Roman books about monsters and the like.

Pliny's natural history had 327 Greek authors as sources he also sited the Bibliotheca historica by Diodorus Siculus a 40 volume work of the worlds history which is thought to have had up to 4,000 cites from various Greek and other works.

No great secrets were displayed and interestingly enough he had no knowledge of Sumer.

Would the Greeks and Roman's have noted aliens, lost continents or even the then existing 'new world'? Pliny did mention the Seres...whom we now call the Chinese and had a great deal to say about the Indians. He of course mentioned Thule and Hyperborea too.

So....unless the Greek and Roman writers of the day were a tad dense they didn't seem to to be able to get to the 'really good' stuff! LOL

However they did do a fair job of describing the world as they saw it.

reply to post by Hanslune


yeah and thats true, the Greeks quest for knowledge and reason is unlike how we think of it today. they might have been dull... but they sure as hell had some great ideas.

others of interest.

Aristarchus of Samos - first to posit heliocentric view of the solar system ( 310 BC – 230 BC) Aristarchus

Thales of Miletus - first "philosopher" and inventor of the scientific method
Thales

my personal fav. Parmenides of Elea - no intro. dont want to spoil it
Parmenides

Originally posted by Byrd
They no longer study the classics in school, and I think it's a bit of a loss. I remember reading Edith Hamilton's book on the Romans and bugging the librarians till they came up with a copy of her book on the Greeks. Amazing woman: en.wikipedia.org...

Two books that greatly influenced my interest in Middle Eastern archaeology!

Well, it's surely very nice to see a post about antiquity not claiming some alien intervention, a super advanced civilization or billions of years old achievements (sure, everything MUST be much older than we are lead to believe, no? ).

Seriously now, Eratosthenes was just one of many ancient Greeks that relied on their logic and intellect to answer things. Aristarchos was another, as mentioned above, Thales, Democritos (Leucippos' pupil, if I recall correctly), Archimedes and a host of others. I focused mainly on the more "scientific" ones, Aristoteles, Plato, Socrates, Parmenides and the rest of the "pure" philosophers I left out, not because they aren't "worth" mentioning, on the contrary. I focus on the scientists because their work is more easy to prove right or wrong.

To address a few remarks.

MrsBlonde,

Eratosthenes was a caretaker to the Library and the Library was built to gather all the knowledge in the world. Not for exploitation or financial gain (as it is the trend today) but for the sake of knowledge itself. For the first time in History, a research institute was established for pure research, or knowledge for the sake of knowledge. I think he was the right man for the job!

monguzi,

You should watch Carl Sagan's Cosmos documentary series. there he speculates about the level of progress we'd enjoy today had the Alexandria Library not burnt down. We'd probably be traveling to the moon 5-6 centuries before we did.

Hans,

The Sumerians were about 2500 years older than the age you describe, without archaeological digs, direct written references and trade records at their disposal it is only natural that Roman historians didn't know about them.
As for aliens or monsters, well, how do you reference to something that does not exist?

Great post

S/F!!

Just to add something..

They say if you multiply the length and width of the Parthenon Temple you get the exact distance of the earth to the moon.. Sacred geometry

Ποιος το λεει αυτο? Σε τι μοναδες μετραμε το μηκος και το πλατος του Παρθενωνα?

Says who? What measuring units does one use in the multiplication?

Originally posted by Maegnas
Ποιος το λεει αυτο? Σε τι μοναδες μετραμε το μηκος και το πλατος του Παρθενωνα?

Says who? What measuring units does one use in the multiplication?

Που να ξέρω εγώ ρε φίλε...

dunno

Αμα δεν ξερεις, μην το αναφερεις!

If not sure, don't spread it around.

Nice to meet a fellow Greek around here!

The Sumerians were about 2500 years older than the age you describe, without archaeological digs, direct written references and trade records at their disposal it is only natural that Roman historians didn't know about them.

Howdy M

That comment was in regards to those who think the LoA had 'secret' information that was lost. As the Roman's had access to the Library or more importantly to the Greek materials producted by research in the Library if records of the Sumerians had existed would probably have shown up. However they didn't

So we agree

There was a history of historical repression, the pharoes for instance, or how could the greek gods be supreme if there were previous gods?..how could certain leaders be the representitive of the gods who invented everything if there was a culture that came before?

We see that as a religious trend continuing into europe with christianity and the current ridiculing of the greek scientists, and their knowledge.

Like the earth is flat business when the greeks and egyptions knew it wasn't

Ancient ME religion tended to see parallels in foreign religions to their own. Most religions had x god in charge of y and so did the other therefore the god were the 'same'.

Repression by all cultures of the same culture in the same way. That would require a remarkable degree of cooperation amongst warring states which had troubles enough controlling their own empires. Considering the language barriers it seem unlikely.

If the Egyptians were trying to repress the concept of Sumer why did the Romans find out and report on the Indian and Chinese cultures? Why was Sumer or Dilmun dangerous to know about but not the really odd religions and cultures of India and China?

The Greeks figured out the world was round when are you saying the AE knew it?