Round or flat?

We're told that the Earth on which we live is a spherical lump of rock suspended in Space, held in its orbit round the Sun by the force of gravity. But go outside and look at your surroundings and the Earth certainly doesn't look round - in fact it looks rather flat! So where did the idea of the spherical Earth come from?

Is it round or is it flat?
Ptolemy produced a map of a globular Earth as early as AD 140 The ancient Greeks didn't do anything energetic like sailing round the world, but they did sit and think a lot. They not only came up with a realistic theory for the shape of the Earth, they also managed an amazingly accurate calculation of its size using trigonometry.

Unfortunately the Mediaeval church rejected the Greek idea, calling it a heresy. Of course the earth was flat - everyone could see that! Above the Earth was Heaven and below the Earth was Hell, and in between lived Man and Woman.

A flat Earth is fine, unless you want to go to sea. The problem for sailors is that if the Earth is flat, then it must have edges. And if it has edges, then boats can fall off them. And if your boat falls off the edge of the world - well…!

So for many years sailors lived in fear of losing sight of land, and sea voyages hugged the coastlines. But through the 14th, 15th and 16th centuries exploration of the oceans of the world began in earnest and islands, countries and continents were discovered.

Who did the exploring?
The drive to discover new lands and different ocean routes was fuelled in two ways. The Christian church in Western Europe was split into Catholics and Protestants - and each side was anxious to convert as many people as possible. Kings sent out expeditions of discover new lands for conversion to their own preferred faith. But a more important factor was greed. The new lands which were found were a source of gold, spices and slaves - and everyone wanted as much as possible of the wealth that was available.

Many famous names completed voyages of discovery - Marco Polo, Christopher Columbus, Vasco Da Gama. The known world expanded with every voyage until it became obvious to all who wanted to see it that the Earth was in fact a sphere. Finally the Victoria, the only surviving ship of Ferdinand Magellan's fleet, circumnavigated (sailed right round) the world. From then on there was evidence that the Earth was NOT flat. The tiny wooden ships that sailed about the world centuries ago against all the odds gave us massive amounts of information about the world we live on, most of which has been confirmed by the methods of exploration available today.

So what does the Earth really look like?
The oceans of the world are no longer uncharted. Ships travel across them regularly and aeroplanes planes fly around the world daily - on journey that used to take years. But the most spectacular evidence for Ptolemy's ideas arrived almost 2000 years late! As the exploration of space began, so it became possible to take pictures of the whole Earth as it appears in space. To see the planet which supports us in the photographs taken from rockets and satellites is amazing thing to do - and dispels any notions of a flat Earth. We can see with our own eyes that the Earth is a sphere.

Find out more -

Go to the Fourmilab Earth Viewer for amazing views of the Earth from space. Choose a satellite and see the view of Earth available to it - then try another, and another. The Earth as a sphere is revealed to us all.

How stuff works explains about satellites and how they work, with lots of pictures of the satellites themselves and what they see in space.

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