How a cosmic coincidence gives Earth its ‘perfect’ solar eclipses

A solar eclipse is a rare, visually striking phenomenon. The Moon passes between Earth and the Sun, temporarily hiding our star – a geometrical alignment spanning millions of miles. A partial solar eclipse occurs when the Moon doesn’t fully block the Sun, resulting in a gentle dimming of the sky. A total solar eclipse, however, dramatically plunges a daytime sky into blackness. Everything has to be perfect for this to happen. An astonishing cosmic coincidence means that solar eclipses as…