Monday, June 24, 2024

Wednesday’s super blue moon – less blue than one might expect. (Photo: Ed Uthman via Flickr)

I hope you caught a glimpse of the moon Wednesday night, because it won’t be back until 2037.

Let me rephrase: The moon will be back, but the so-called “super blue moon,” a rare type of full moon that graced the heavens Wednesday, won’t return for more than a decade.

The last super blue moon occurred in December 2009, meaning these shy moons might wait nearly 20 years before returning. What makes this event so rare? Well, a super blue moon requires two uncommon events to coincide.

The first requirement is a supermoon. Because the moon orbits Earth – or, for the physics buffs, the earth-moon system’s center of mass – on an elliptical orbit, there is a point at which the moon is closest to Earth, named the perigee. When the moon happens to be full at the perigee, a supermoon results.

Despite their regal names, supermoons aren’t that super. They appear about 14 percent larger than the average full moon. That difference, according to NASA, is about the same between a quarter and a nickel. Supermoons aren’t all that rare either, as they account for almost a quarter of full moons.

The second requirement is a blue moon, which you probably already gathered. Contrary to popular belief, a blue moon does not emit a sapphire aura. Besides a refreshing ale, it is actually the second full moon in a calendar month. It takes the moon 29.5 days to fully orbit the earth, a few hours shorter than the average month of our solar calendar. So, once in a blue moon, we can get a month such as this August, when we had a full moon on the first and another on the last night.

Speaking of the phrase “once in a blue moon,” we can actually calculate this ambiguous unit. Blue moons, according to NASA, account for about 3 percent of all full moons. That equates to about once every 33 months or 2.75 years.

For those who missed the super blue moon, which was neither super nor blue, don’t fret: When the super blue moon returns in January 2037, it will bring a buddy, which will follow in March 2037.