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That's a pretty cool trick. [May. 28th, 2006|01:45 pm]
randomposting
[mood |headachey]
[music |Bonnie Bear?]

Erathosthenes estimated the circumference of the earth within one percent -- about 200 years B.C.
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Comments:
From: duke_otterland
2006-05-28 06:46 pm (UTC)
I wonder how so.
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[User Picture]From: randomposting
2006-05-28 06:51 pm (UTC)
Here's some info from Wikipedia. Eratosthenes knew that on the summer solstice at local noon in the town of Syene on the Tropic of Cancer, the Sun would appear at the zenith, directly overhead.

He also knew, from measurement, that in his hometown of Alexandria, the angle of elevation of the Sun would be 7° south of the zenith at the same time. Assuming that Alexandria was due north of Syene he concluded that the distance from Alexandria to Syene must be 7/360 of the total circumference of the Earth. The distance between the cities was known from caravan travellings to be about 5000 stadia: approximately 800 km. He established a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. The exact size of the stadion he used is no longer known (the common Attic stadion was about 185 m), but it is generally believed that Eratosthenes' value corresponds to 39,690 km.

Although his method was correct, some of his assumptions and measurements were not. Syene is not exactly on the Tropic of Cancer but rather slightly north of it, and is not directly south of Alexandria; nor is the Sun at infinite distance. (Eratosthenes knew the latter, but we are not told he corrected for it.) More seriously, angles in antiquity could be measured only to degrees or quarter-degrees, and measurement of overland distances was worse. The circumference of the Earth around the poles is now measured at around 40,008 km.

Eratosthenes' method was used by Posidonius about 150 years later.

About 200 BC Eratosthenes is thought to have coined or to have adopted the word geography, the descriptive study of the Earth.


http://en.wikipedia.org/wiki/Eratosthenes
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[User Picture]From: sapphirezelda
2006-05-28 06:50 pm (UTC)
SO CLOSE!
lol
Smart kids
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[User Picture]From: randomposting
2006-05-28 06:53 pm (UTC)
Indeed. ;)
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From: truelovechild
2006-05-28 06:52 pm (UTC)
The greeks were damn smart. That's all there is to it.
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[User Picture]From: randomposting
2006-05-28 07:03 pm (UTC)
Absolutely agreed!
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[User Picture]From: nebris
2006-05-28 07:02 pm (UTC)
One of the greatest crimes in history was the burning of the library of Alexandria.

~M~
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[User Picture]From: randomposting
2006-05-28 07:11 pm (UTC)
Absolutely agreeed. It brings me to tears just thinking about it. Can you imagine the wealth contained therein. Such a crime.
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[User Picture]From: randomposting
2006-05-28 07:13 pm (UTC)
And nuh uhh... his son even reads my LJ. Look at my icon. ;)
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[User Picture]From: nebris
2006-05-28 07:42 pm (UTC)
Hey, I know that guy! lol

~M~
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[User Picture]From: randomposting
2006-05-28 08:03 pm (UTC)
Brothers!

(We're close!)
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[User Picture]From: nebris
2006-05-28 09:11 pm (UTC)
We should start a vaudeville act. lol

~M~
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[User Picture]From: randomposting
2006-05-28 09:12 pm (UTC)
We'd rock!
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[User Picture]From: nebris
2006-05-28 09:19 pm (UTC)
Totally! ;D

~M~
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From: goodtouch
2006-05-28 08:12 pm (UTC)
Ah, someone's been watching the Science Challen, eh? :)
It's so interesting how he noticed shadow lengths being different at the same time. That's one of those things that is so seemingly obvious you'd never notice. I wish I was that smart! lol
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[User Picture]From: randomposting
2006-05-28 08:20 pm (UTC)
Oooh! Good call!

And yeah. I've been watching lots of "educational" and "historical" tv lately. ;) I gotta do something while waiting for my HBO series.
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From: lostways
2006-05-28 09:41 pm (UTC)
Seee... TIMe Travel does work, as they said you can always go back in time but never forward with a name like that you have to wonder if it really is a past name or some crazy future time traveling name

THink about it!

or not poor headache randomd *give brain massage*
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[User Picture]From: randomposting
2006-05-28 10:33 pm (UTC)
Aww, thanks babe. Anti migraine medicine helped.
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From: i_love_soup
2006-05-29 01:52 am (UTC)
first off it definitely sounds like a future time traveling name second sorry i'm about to be really nerdy here, and i know this isn't what you were talking about, but in theory time travel actually is possible...according to einstein's whole special relativity thing it's possible to travel into the future but not back in time.
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From: lostways
2006-05-29 01:55 am (UTC)
EH? well its kind of realtivity supposely traveling at the speed of light it seem time just kind of stops and ya either age faster or slower i can't remember i won't know if that's really time travel more like the effects of light speed would have a on living creature .. then again we dotn have that power to do it yet, so yes your quite correct
but i have always thought because the future is never set you coudln't go forward... but back ward ya can and only if you must because it already happen
but that's what i think
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From: i_love_soup
2006-05-29 03:47 am (UTC)
yay you speak physics...and yeah it's not quite like back to the future time travel, and has nothing to do with the philosophical idea of time travel...i just think it's kind of a cool science thing, it's fun to think about anyway! =>
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From: lostways
2006-05-29 03:58 am (UTC)
yeah, i like to think about such things have you seen donnie darko?
if not ya may like it, I like to ix a little phsyic philosopcaial idea
i mean if ya dont mix them both then where is the fun?
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From: i_love_soup
2006-05-29 05:50 am (UTC)
uh oh confession time, i haven't seen donnie darko. the one time i was going to watch it we watched edward scissor hands first and then i fell asleep and woke up in the middle and there was this scary looking bunny on the screen, and i decided that if i watched it from the middle it would just ruin the movie, so i went back to sleep. but i hear it's good and have every inention of seeing it someday. haha and now when i finally do i'll think of livejournal.
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From: lostways
2006-05-29 05:51 am (UTC)
it's always has to be the guy with the cute stuff pengun to remind the people of great movies =p
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[User Picture]From: faerie_mistress
2006-05-28 11:52 pm (UTC)
Shiny. Shame he never had any way of actally knowing if he was right.
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[User Picture]From: randomposting
2006-05-28 11:58 pm (UTC)
Maybe he found out. *shrug* I don't know what happens to us after we die.
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[User Picture]From: xenaamazon
2006-05-30 06:11 pm (UTC)

Wow.

Yup :)
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[User Picture]From: duckfast
2006-06-02 08:38 pm (UTC)
he had some brains. and why did people still think the earth was flat?
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[User Picture]From: randomposting
2006-06-03 01:26 am (UTC)
Because people ain't smart. ;)
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