Total solar eclipses: magic, science and wonder

Abstract

Imagine that we are in the middle of a field, thousands of years ago. It is a beautiful summer's day: blue sky, no clouds, no wind. At noon, it feels quite hot. Then we sense the temperature falling, and the light fading, but it is still a beautiful day – blue sky, no clouds, no wind. Soon the air turns much cooler and the sky much darker. There are still no clouds, but a gentle, cool breeze has picked up. The Sun is still too bright to look at, but it is fading away, and near to it we can see bright planets, as we would at night. The western horizon turns a dark shade of blue-grey, and then, in just a few short seconds, darkness invades the landscape. We look up in terror and see that the Sun has been replaced by a black disc, surrounded by what seems like a ghostly veil of white smoke or steam. The Sun – the most important thing in the sky, our source of light and heat, our clock and calendar – is no longer there.