What is a total solar eclipse?

Melanie photographing the partial phase of the total solar eclipse in Eola Hills vineyard, Oregon, USA, on 21st August 2017.

A total solar eclipse is a fascinating and beautiful phenomenon and creates unique conditions for scientific measurement. But what exactly is it?

What is a total solar eclipse?

A solar eclipse occurs when the Moon passes between the Sun and the Earth, blocking the light of the Sun. How, precisely, they line up determines the type of eclipse we see – a partial, total or...