top of page

Walk Softly – Once in a Blue Moon

by Geoffrey Carpentier

Generally, nobody is surprised to look up at the night sky and see the moon, but sometimes, it seems to change dramatically in size and colour. Why is that? More on that in a moment.

Firstly, the Moon was simply named the 'moon' because, early scientists and astronomers didn't even know if other similar objects existed in the universe. Its name is based on the Latin 'luna' meaning 'moon'. I must admit I was hoping it might have had a more profound genesis! It was when Galileo came on the scene, people realized we weren't alone in the universe, so subsequently, moons from other planets were given specific names.

The most common theory on why we even have a moon stems from the belief, some Mars-sized body collided with Earth, it is thought to have occurred about 4.5 billion ago. The debris from the collision accumulated in space, within Earth's gravitational field, and formed a molten body which eventually cooled, crystallized and hardened to form our present-day Moon. Now, this theory doesn't explain why the Earth even survived the impact. Considering the devastation a much smaller asteroid (about 10 km in diameter) caused, when it collided with us. This is believed to have happened approximately 66 million years ago and is presented as what presumably killed the dinosaurs.

Now, back to our story. Meteorologists seem bent on having names for every weather-related phenomenon, no matter how trivial, but naming the different ways our Moon appears has merit and is, of course, very interesting.

'Once in a Blue Moon' is a phrase we all know, but really few have any idea if they've ever seen one. The name would seem to indicate they must be rare, yet apparently, a Blue Moon is fairly common. It refers to situations where two full moons occur within a calendar month; but is the moon really blue? Well, not really, although under some atmospheric conditions, it may have a blue hue, due to light moving through airborne dust particles. On average, we can expect to see a Blue Moon about every 2.5 years.

A Super Moon, correctly called a Perigean Full Moon, is a state when the Moon looks abnormally large (i.e. up to 30% brighter and 15% larger). It occurs when the Moon is most closely situated compared to Earth.

A Blood Moon is evident when the Moon dips low in the sky during a total lunar eclipse, whereby a reddish glow is cast across the moon's surface. Occasionally, more than one of these lunar spectacles occurs simultaneously. This most recently occurred in 1982 and 2018, and the next event will occur in 2027, when all three lunar events coincide. This phenomenon is called a Super Blue Blood Moon – wow, really?! Interestingly, if a second new moon occurs in a month (e.g. that can only occur about every 32 months on average), a Black Moon is said to have occurred. Really, the Moon is still there, of course, but the darkness is so intense only the faintest sliver of light along part of its circumference may be visible.

On the flip side, sometimes the Moon looks tiny since it is at its farthest point from Earth, as it travels along its elliptical path, and is called a Micromoon.

Finally, a Harvest Moon refers to the full, bright moon which occurs closest to the September equinox. The name dates from days before electricity when farmers depended on the Moon's light to harvest their crops into the night.

Now, I found this next piece particularly interesting, but admittedly couldn't find definitive references to support it. It is claimed, both North American and European indigenous cultures named each moon after an event which was important to their culture. Consequently, we have moons called Wolf (January), Snow (February), Worm (March), Pink (April), Flower (May), Strawberry (June), Buck (July), Sturgeon (August), Corn (September), Hunter's (October), Beaver (November) and Cold (December). I would like to learn more about these if anyone has information they'd like to share.

The Moon is a fascinating object which grabs and holds our attention. Maybe you can understand it a bit better now.

Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff on-line on LinkedIn, Facebook and Instagram.

18 views0 comments

Recent Posts

See All


bottom of page