Super Blue Moon
Earlier this year, we investigated the many flavors of the moon.
Despite the fact that we only see one face of our satellite, we are treated to a plethora of different visuals. We have all the phases, with their crescents, humps (“gibbous moon”), fulls, and quarters. Every once in a while, we’re treated to eclipses. The moon inhabited so much of our ancestors’ lives that they gave each month’s full moon a unique name (wolf, pink, flower, sturgeon, beaver, etc.).
Most times, a calendar month features just one full moon. That’s not a coincidence, as the words “month” and “moon” are closely related. Sometimes, though, a second full moon occurs during one month. When this transpires, we call the second full moon a blue moon. This event is rather uncommon; a blue moon tends to happen once in a…blue moon (in reality, it’s every two or three years). Unfortunately, a blue moon isn’t colored blue, though that would be fantastic.
We also learned about the so-called supermoon. The moon travels around Earth in an elliptic orbit. This non-circular orbit means the moon sports an apogee and a perigee, fancy terms for the point farthest away from Earth during its orbit and closest. When a moon happens to be full in proximity to the perigee, we have dubbed this occurrence a supermoon. Since Luna is slightly closer than normal, she appears a bit bigger and brighter than usual.
A supermoon sounds pretty stupendous. Will you be able to notice a marked difference from a non-supermoon? The answer is less super than one might guess.
A supermoon is, undoubtedly, larger in the sky, as it is closer. However, the supermoon is only about 7% larger than the average full moon. To many people, this disparity will be hard to spot.
Compared to the opposite of a supermoon, sometimes dubbed the micromoon (a full moon at its apogee), the supermoon is 14% bigger. According to NASA, that’s like looking at the size difference between a quarter and a nickel. The agency does note, however, that the supermoon will be 30% brighter than the micromoon. That figure verges into the noticeable.
Check out the difference between a supermoon and a micromoon from 2020 in the NASA images below. Click on the image to open up an article that includes a wonderful before-and-after slider for the graphic, so you can compare their sizes on top of each other.
Though a supermoon does indeed contain superlative properties, perhaps not as many as the nomenclature might imply. Does part of the super-ness arrive via rarity, then? Nope! Supermoons occur three or four times a year. Roughly one-quarter of all full moons are supermoons. According to Hayden Planetarium’s Joe Rao, astronomers used to coin these fulls as “perigean full moons” and the public did not give a hoot. Now, however, the supermoon often receives plenty of attention in the news and online. That’s the astronomical power of words at work.
In August 2023, the starry media machine is in full gear, in reference to the Super Blue Moon.
On Wednesday and Thursday, 30-31 August 2023, one can watch a full moon that is both super and blue. This overlap is actually quite rare. NASA pegs the average between super blue moons to be 10 years, though the number can go as high as 20. If you miss the August 2023 super blue moon, your next chance to catch one will not be until January 2037!
The previous super blue moon transpired on 31 January 2018. This instance added an extra layer of cool factor, as it was what scientists call the “Trifecta.” This full moon wasn’t just a super blue moon, it was a super blue blood moon! The “blood” portion comes from the fact that it coincided with a lunar eclipse, which often turns the moon a pale red color during the event. As wonderful as a super blue moon is, the Trifecta easily topples it.
Did you miss the super blue blood moon in 2018?
Fret not, the 2037 super blue moon will also be a super blue blood moon!
Supposing 13.5 years is a rather long time to wait, go outside this week to behold the super blue moon. If this full moon isn’t enough to get you into the dark, you’ll also have a shot to see Saturn near the super blue moon. Just five-and-a-half degrees to the upper right, the system’s second-biggest planet will appear to be a bright star to the naked eye. Break out your binoculars and you just might get a glimpse of the famous rings!
If you can’t view the moon outdoors or happen to have foul weather, check out a live stream instead:
Further Reading and Exploration
Super Blue Moons: Your Questions Answered – NASA
August’s rare Super Blue Moon, the biggest full moon of 2023, rises this week – Space
How Rare Is the ‘Super Blue Moon’ Appearing in Skies Later This Week? – Smithsonian Magazine