We now know that if the Earth were a flat disc instead of a sphere, gravity would also tend to pull people at the edges inwards towards the centre, not just down towards the surface-with all sorts of strange effects that we do not observe. The Greek mathematician Eratosthenes and the Roman-Greek-Egyptian mathematician Ptolemy were able to estimate the circumference of the Earth quite accurately, by measuring the angle of the sun in different places at the same time. Indeed people were able to demonstrate this in several ways more than two thousand years ago.Īristotle, for instance, observed that the Earth’s shadow on the moon during a lunar eclipse is always circular.
There are many ways to prove that the Earth is spherical. You can help us take action – and get our regular free email
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