In medieval times people thought the world was flat, right? Wrong.
From the big names of ancient Greece and Muslim astronomers to the Christian era we've long known the world was round.
So who started the flat earth myth myth?
There are many illusions about bygone times. One of the most common ones is that the inhabitants of medieval Europe believed that the earth was flat.
But it's simply not true. In fact, we've known the earth to be a ball (or a sphere) for a long time.
About 2500 years ago, Pythagoras (582--507 BC) postulated that the earth was spherical, not just a flat circular disc.
Aristotle (384--322 BC) agreed.
First, what about lunar eclipses, he said, where the shadow of the earth falls on the moon? These can happen when the moon is close to the horizon, or high in the sky.
So, if the earth were a flat disc, every now and then, there would be a lunar eclipse in which the light of the sun would hit the supposed disc of the earth at an angle, not square on.
This would produce an ellipse on the surface of the moon. But instead, every lunar eclipse has the earth throwing a circular shadow onto the moon, so the earth has to be spherical.
Second, said Aristotle, sailors knew that when seeing a distant ship, they would first glimpse the top of the mast, before sighting the rest of the ship.
And third, some constellations only rise a little above the horizon in the northern hemisphere. But, said Aristotle, when travellers went further south, they saw these constellations rise higher in the sky. This was possible only with a spherical earth.
About a century later, Eratosthenes of Cyrene (276--195 BC), the second librarian of Alexandria, did some very simple geometry based on the length of shadows.
He estimated the circumference of the spherical earth, and got to within two per cent of the correct figure!
And well into the next millennium, around 830 AD, the Muslim astronomers of Calip al-Ma'mun did a series of measurements, and got to within 0.5 per cent of the correct figure.
So, for the last 2500 years, in Europe and in the Middle East, the flat-earthers were in a very small minority. At least, this is what the historian Jeffrey Burton Russell, of the University of California at Santa Barbara, reckons.
His book, In Inventing the Flat Earth, claims that since the third century BC, practically all educated people in the western world believed in a spherical earth.
Looking as a historian into the historical record, he found tens of thousands of Christian theologians, poets, artists and scientists who believed that the earth was a sphere.
On the other hand, he could find only five Christian authorities who believed in a flat earth.
Dr Russell wrote:
"In the first fifteen centuries of the Christian era, five writers seem to have denied the globe, and a few others were ambiguous or uninterested in the question. But nearly unanimous scholarly opinion pronounced the earth spherical, and by the fifteenth century all doubt had disappeared."
In fact, Burton found that the myth was started in the 1830s by a Frenchman and an American, acting independently.
The Frenchman was Antoine-Jean Letronne (1787--1848), an antireligious academic of great renown. He wrote On the Cosmographical Ideas of the Church Fathers in 1834.
He deliberately misrepresented medieval Christians as being scientifically ignorant, and his supposed proof for this incorrect claim was that they believed in a flat earth. But of course they did not believe in a flat earth.
The American identified by Burton was Washington Irving (1783--1859), who wrote his history of Christopher Columbus in 1828. Columbus wanted to sail west to China, Japan and India.
Irving painted a colourful and dramatic word picture of Columbus trying to convince a board of flat-earther inquisitors (the Council of Salamanca) that the earth was round, so that he could get funding.
Like all good myths, there is an element of truth here. Columbus did meet with a board of scientists. The scientists claimed that Columbus' distances for getting to the east by sailing west were wildly wrong -- actually 20,000 nautical miles, rather than the 5000 claimed by Columbus.
The scientists were correct, and Columbus would have perished. But luckily, he happened across some islands off the American coast that he called the Indies, believing that he had sailed to India.
"If God or good luck had not put America -- the West Indies -- in the way to catch him, Columbus and his crews might indeed have perished, not from falling off the Earth but from starvation and thirst."
Various educational authorities of the day put the Irving version of the Council of Salamanca in their school textbooks, and the myth spread through the USA, Europe and elsewhere.
It received an enormous boost after the publication of Darwin's The Origin of Species in 1859. The evolutionists unfairly claimed that the creationists believed in a flat earth, as an example of how unscientific they were.
But how times have changed. At least one thing that the evolutionists and creationists can agree on is the fact that the earth is not flat.
1.What is an illusion that we have about medieval times?
2. What did Pythagoras do 2500 years ago?
3. What kind of shadow does the earth cast on the moon?
4. How accurate were the calculations of Eratosthenes of Cyrene 2300 years ago?
5. Who were the people who started the flat earth myth?
6. How good was Christopher Columbus at maths? (Give evidence)
7. What happened after the publication of “The Origin of the Species”?
In 300 – 500 words write a summary of the passage