A green flash is sometimes seen just as the sun sets or rises. This occurs because green light is bent most strongly by the atmosphere. So the green is seen before other colours at sunrise, and after the other colours have vanished at sunset.

Most planets rotate counter-clockwise, but a few - Venus, Uranus and Pluto - rotate clockwise.

In 1784, John Michell presented an argument in favour of the proposition that the stars were light years distant from the Earth. It would be another 54 years before the German astronomer Friedrich Wilhelm Bessel would prove the truth of Michell's assertion by making the first-ever measurement of the distance to a star.