Through a haze of dust is the same moon we see every night, but in this case, it is blue. The last Blue Moon we saw was in August of 2021, and based on recent research, the moon turns blue every two or three years.

A Blue Moon happens roughly every 33 months and is caused by dust particles entering our atmosphere, creating a color filter that changes the moon’s appearance. Most of the time, these moons are caused by volcanic eruptions.

According to yogajournal.com, in the 16th century, many people believed that when the moon turned blue, it represented luck and magic. In other words, they thought the moon would turn blue because of extraterrestrial life.

We now know, though, that this phenomenon is caused by the moon turning full twice in the same month. 

According to Atmospheric Optics expert Les Cowley, a person’s eyes have automatic ‘white balances’ like digital cameras. So, when a person goes outdoors from a cabin, for example, lit by an oil lamp (yellow light), the moon will appear blue until one’s eyes adjust.

This is essentially the reason why we perceive the moon as blue. However, the blue moon is not the only color change we see. The other color changes we rarely see are the orange (“Blood Moon”) and the Pink moon. Although these moons are rare, the beloved blue moon is the rarest.

There is a reason why people reference the old saying “once in a blue moon.”