The Dark Side of the Moon

What do people mean when they talk about ‘the dark side of the Moon’? Is there a dark side of the Moon at all? How did this strange phrase originate?

This popular phrase is usually misunderstood. Astronomers often object strongly, ‘The far side of the Moon gets the same amount of sunlight as the visible near side’. They are both correct and incorrect. In terms of solar illumination they’re correct, of course.

But good astronomers are not necessarily good linguists. The word ‘dark’ in this phrase does not mean absence of light, it means hidden from view or obscured. Dark meant ‘hidden’ or ‘secret’ long before it came to be used to mean an absence of light. See the Wiktionary definition.

Here’s a nice NASA video illustrating the dark (hidden) side of the Moon. You’ll notice it has night and day periods of course, just like the near side.