As the schoolboy version of history has it, in 1492 people thought the Earth was flat. When Christopher Columbus set sail for India they thought he would fall off the edge of the Earth.

I think most OLO posters know better. The rotundity of the Earth was well established by 1492. A man called Eratosthenes had published a remarkably precise estimate of the circumference of the Earth 1,700 years previously. You can read about it here:

http://www.gap-system.org/~history/Biographies/Eratosthenes.html

However in 1492 some people thought Eratosthenes estimate way to large. Among them was Toscanelli, an Italian mathematician. He convinced Columbus that the Earth was small enough to make the journey to India feasible

And that’s what the argument was about. If Toscanelli was right Columbus’ expedition could make it to India before they ran out of food and water.

On the other hand, if Eratosthenes’ 1,700 year old estimate was correct, Columbus and his crew would run out of food and water and perish at sea before they could reach India.

Well Toscanelli was wrong. Eratosthenes was right. But luckily for Columbus there was America.

So Columbus and his crew were able to replenish their stocks of food and water, infect a few “Indians” with syphilis and return to Europe.

I think that makes Columbus the luckiest man in history.

Columbus died believing he had reached India.

Or can anyone think of a luckier man? Other than Columbus' crew of course. They were equally fortunate that America existed.

nice try steven
but im more concerned about ending rather more recxent colonisations

like that of israel
who still thinks they rule the world
[talk about the flat earthing 'gods chosen'..lol]

anyhow thanks for raising the colonisation issue
will get some links for the latest
libia
http://www.youtube.com/watch?v=qogT-DDKHgQ&feature=related
http://www.pambazuka.org/en/category/features/72575
ot syria
or palestein
or maybe the civil war in bahrein
http://news.yahoo.com/s/ap/20110428/ap_on_re_mi_ea/ml_bahrain

there dont seem to be an end to those thinking
their flat earth vieuw is the only relivant vieuw

oh well off to read
the news i missed through
the other media destraction's
http://whatreallyhappened.com/

so many other more recent destractions need attention
http://theintelhub.com/2011/04/28/billboard-company-cancels-equal-rights-for-palestinians/
http://mycatbirdseat.com/2011/04/shadow-of-syrian-conflict-stretching-into-lebanon/
http://weeklyintercept.blogspot.com/2011/04/student-loan-debt-hell-21-statistics.html
http://weeklyintercept.blogspot.com/2011/04/petraeus-to-cia-completes-cheneys-dream.html

http://revolutionarypolitics.com/?p=5459
http://snardfarker.ning.com/group/gold_silver_precious_metals/forum/topics/us-gets-c-credit-rating-lower
fake el cia-rda
http://www.youtube.com/watch?v=GsUtvOW6SR0&feature=player_embedded
http://whatreallyhappened.com/WRHARTICLES/fakealqaeda.html
then of course the gaza flotilla
[cant find a link]
oh well visit the main link

other palistein stuff
http://www.reuters.com/article/2011/04/27/us-palestinians-reconciliation-idUSTRE73Q50820110427
http://desertpeace.wordpress.com/2011/04/28/israel-can-have-a-peace-partner-with-a-unified-palestine-but-will-palestine-have-one/
http://www.bbc.co.uk/news/world-middle-east-13221843
http://www.intifada-palestine.com/2011/04/no-fly-zone-over-gaza-%E2%80%94-petition-video/
http://www.rys2sense.com/anti-neocons/viewtopic.php?f=11&t=24551&p=156151#p156151

why do i think stuxnet[israels hand
in 'the cloud' info going south]
http://www.businessinsider.com/amazon-lost-data-2011-4

OUG

LOL

I know you will find this hard to grasp but I’ll try anyway.

Even if I don’t convince you maybe I’ll be able to stop this thread being HIJACKED with IRRELEVANCIES.

Though I am Jewish and though I freely confess to being an Israel supporter I am not nearly as obsessed with Israel as you appear to be.

Sometimes interesting historical trivia is just interesting historical trivia.

Sometimes I post things because I find them interesting and want to share.

And that’s all my original post is.

Nothing more.

Yes Eratosthenes is most gob-smacking for sheer cleverness. The fact that anyone thought he was only in the second rank of thinkers is also pretty gob-smacking, and testimony to the astounding debt we owe the ancient Greeks.

The article you linked to on Eratosthenes didn't mention two facts that deserve mention.

The first reason why Eratosthenes thought the earth was a sphere in the first place, was that when he was at Aswan, he noticed that the midday sun shone right down to the bottom of a well at noon at the summer solstice; but when he was at Alexandria, he noticed that the sun did *not* shine to the bottom of a well at noon at the summer solstice, but aslant.

Now I ask you. Would *you* have noticed that? If you had, would you have concluded that it must show the earth's shape is spherical? Gob-smacking.

The next reason why he thought the earth was a sphere was from watching an eclipse of the moon. He saw that the shadow cast was curved, and deduced from his geometry that the only thing that would cause that is a sphere.

He then paid a guy to walk from Aswan to Alexandria (a long way) with a little measuring device. This gave him the arc which he had to multiply out to get the circumference. (The error comes from the error in the measurement of the arc.) God was that guy ever clever.

There was another clever Greek who figured out the height of the great pyramid. Not even the Egyptians knew what is was at the time. Know how he figured it out? He waited until his shadow was the same length as his height and then measured the shadow of the great pyramid.

However I must differ with you in nominating Columbus the luckiest man in history. This title must go to the Great Khan whom Marco Polo met. It's mainly the description of the clever administration of his bedchamber that must strip poor old Christopher of his claim.

Thank you for your fascinating link stevenlmeyer.

What a guy was Erastosthenes and a muso as well.

Peter Hume, Thinker 2

Thank you for your kind words:

You may enjoy this piece on Aristarchus.

http://www.astro.cornell.edu/academics/courses/astro2201/aristarchus.htm

Aristarchus was the first person we know of to:

--Deduce that the moon was smaller than the Earth while the sun was much bigger.

--Provide an estimate of the distances from the Earth to the moon and sun

--Hypothesise that, since the sun was so much bigger than the Earth, it was the Earth that orbited the sun rather than vice versa

And he did it all with naked eye astronomy 2300 years ago.

BTW by the time of Eratosthenes the Greeks had already guessed that the Earth was a sphere. There were three main give-aways:

--The masts of sailing ships seemed to sink as they got further from shore; AND

--Certain stars and constellations appeared lower in the sky as you went further South; AND

--As you went further South entirely new constellations appeared.

The Greeks and those, like Eratosthenes who were "Hellenised" were SMART!

In fact that whole Eastern Mediterranean area was a hot-bed of scientific enquiry.

Yes it's fascinating how they were so far ahead of everyone else.

Also bronze at that time was only about a thousand years old. So it makes you wonder how much of this great body of knowledge existed during neolithic times, ie, how advanced in knowledge stone age man was.

It is to the eternal disgrace of the Christian religion that they knowingly suppressed all that. Christianity was born into the Greek intellectual milieu of the eastern Roman empire. It was obvious to the early Christian fathers, that, if they followed the rational methods of the Greeks, they would find themselves logically disproved. So what did they do? They deliberately preferred blind faith, and illogic, and authority, over reason! Justinian closed the schools of philosophy at Athens. That's pretty gobsmacking too. Makes you wonder how advanced in the sciences we would have been but for that.

Peter,

So ...... because Eratosthenes and Aristarchus could come up with some brilliant insights, and ways to demonstrate them, on the back of some hundreds of years of scientific discoveries, commercial sopphistication and political development, therefore it just goes to show " ... how advanced in knowledge stone age man was ..." ?

Bit of a long bow, mate :)

No it doesn't go to show how advanced in knolwedge stone age man was, but it does raise the question how much of the ancients' body of knowledge, for example about astronomy and geometry, was accumulated before the advent of bronze, i.e. during the stone age.

Yes, you're right, Peter, especially since the beginning of the agricultural revolution, the neolithic proper: the ability to produce surpluses, to trade in different high-value products and therefore trade caravans and shipping, the need to store, to understand procreation and reproduction (i.e. of animals and plants), to aggregate communities into states and finance those states through taxation and tribute systems - and therefore the need to be able to measure distances, area and weights and to record transactions and stories, and therefore create the beginnings of basic education systems.

I agree that all of this formed the foundation for the development of Greek advances in so many intellectual fields. It's a fascinating and rich field of study.

Joe