Does the Moon Really Have 8 Phases? Who Says?

Quick! Before reading any further, try to name all the phases of the Moon.

Can you do it?

I’ll wait…

(Here’s the answer if you can’t)

1. New Moon
2. Waxing Crescent Moon
3. First Quarter Moon
4. Waxing Gibbous Moon
5. Full Moon
6. Waning Gibbous Moon
7. Last Quarter Moon
8. Waning Crescent Moon

After that, the cycle starts all over again with another darkened New Moon.

But who says the Moon has 8 phases?

But why eight phases? After all, who says there’s only one phase between a New Moon and a First Quarter Moon? Couldn’t we call that 2 phases? Or more?

The reality is that those 8 phases are really just arbitrary divisions. When the Sun’s light moves across the Moon’s surface over the course of the lunar cycle, the phase of the Moon grows or shrinks smoothly and slowly. It doesn’t skip abruptly from phase to phase. So the reality is, there could just as easily be 4 phases of the Moon. Or 16 phases. Or 1000 phases.

The reason we use the above list of 8 phases is really because they’re easy to identify. It turns out that we humans can easily distinguish between the narrow crescent moons and the plump gibbous moons. Likewise we can easily identify both of the half illuminated  quarter-moons. And of course, the New Moon is dark. And the Full Moon is fully illuminated.

So the answer is: We decided on 8 phases because they’re all relatively distinct shapes that we can distinguish between. [And of course the new moon has no shape at all -Ed]

While those 8 divisions may seem logical to us, not everyone has always felt that way. In fact, it wasn’t until the 20th century that the Moon’s 8 phases became universally accepted.

The Moon in Other Cultures

Native American Cultures

The Native American tribes of North America believed in just 2 phases: The New Moon and the Full Moon. They saw the moon as a constant cycle between light and dark. In their view: The full moon phase represented light, and the new moon phase represented dark. Everything in-between was simply a transitional state of flux between the Moon’s two phases.

Ancient Mayans

The Ancient Mayans actually believed in a lunar cycle that had 4 distinct phases. These phases are basically the same as our phases, minus the crescent and gibbous transitional phases.

1. New
2. First-quarter
3. Full
4. Last quarter

Hindu Calendar

Even more interesting, the Hindu lunar calendar has no phases at all. According to Hindu philosophy, the Moon is in a constant and never-ending state of flux.  Trying to force arbitrary “stopping points” along the lunar cycle made little sense to them. Instead, the ancient Hindu calendar placed sacred significance only on whether the Moon was undergoing a process of waxing or waning. In other words: Whether energy is rising or falling.

So the next time someone asks you what the current Moon Phase is, keep in mind that the answer is actually an arbitrary cultural distinction, and somewhere else in the world, they might have a very different answer.

Want to find the Moon Phase for any given date? Try our popular Moon Phase Calendar