All posts by David Carlstrom

What Is a Blue Moon?

Is there really such a thing? Well, yes, but it’s probably not what you may think, and it’s definitely not what it used to be. Calling the moon blue was an obvious absurdity, like saying it was made of green cheese. The phrase, “until a blue moon” developed in the 19th century, meaning never, or at least extremely unlikely. After all, they do occur.

In 1883, an Indonesian volcano named Krakatoa exploded. Scientists liken the blast to a 100-megaton nuclear bomb. Fully 600 km away, people heard the noise as loud as a cannon shot. Plumes of ash rose to the very top of Earth’s atmosphere. And the moon turned blue. Krakatoa’s ash was the reason. Some of the ash-clouds were filled with particles about 1 micron (one millionth of a meter) wide–the right size to strongly scatter red light, while allowing other colors to pass. White moonbeams shining through the clouds emerged blue, and sometimes green. Blue moons persisted for years after the eruption. People also saw lavender suns and, for the first time, noctilucent clouds. The ash caused “such vivid red sunsets that fire engines were called out in New York, Poughkeepsie, and New Haven to quench the apparent conflagration,” according to volcanologist Scott Rowland at the University of Hawaii.

Other less potent volcanos have turned the moon blue, too. People saw blue moons in 1983, for instance, after the eruption of the El Chichon volcano in Mexico. And there are reports of some caused by Mt. St. Helens in 1980 and Mount Pinatubo in 1991. The key to a blue moon is having in the air lots of particles slightly wider than the wavelength of red light (0.7 micron)–and no other sizes present. This is rare, but volcanoes sometimes spit out such clouds, as do forest fires.

The use of the phrase blue moon to indicate an actual astronomical phenomenon first started in 1932 with the Maine Farmer’s Almanac. It’s definition was a season with four full moons rather than the usual three, where the third of four full moons would be called a “blue moon.” That definition mutated into the one most quoted today when in 1946, an article in an astronomy magazine by amateur astronomer James Hugh Pruett misinterpreted the Maine rule to mean two full moons in one month.

Whether you use the newer definition or the one from the Maine Farmer’s Almanac, a blue moon, while not common, happens on a regular basis. Either way, they occur approximately 7 times in a 19 year period.

So, will you ever see a blue moon? In astronomical terms, it is very likely. During this month of December, you may have seen the full moon on December 2nd. If you missed that, the second full moon will be New Year’s Eve, December 31st, when you may be able to see a blue moon, if the weather cooperates.

Blaze Cunningham, Lt Col CAP

Director, Aerospace Education

HQ, Minnesota Wing


BlackCAP Thank You

Thank you Civil Air Patrol and Red Wing Squadron for the BlackCAP experience. I can’t compare it to anything I’ve ever done and I can’t get the faces, conversations, and activities out of my mind. I want to go to encampment now. I had to adjust when I went home on Sunday
from 100+ cadets saying, “Yes, Sir.” and complying to my two-year-old ignoring me while walking up the driveway and out of safety bounds.The experience also became humbling Monday when I was able to cross-reference names with positions, accomplishments, and time in service. Many of the people with whom I was jabbering, with whom I stood in flight, and with whom I worked to solve problems, were very accomplished in their fields and in CAP. However, they never really spent any time talking about those accomplishments. They were humble servant-leaders interested in doing their jobs and sharing the experience.These traits are probably obvious to those of you who have been in CAP for sometime, but I found them refreshingly remarkable, just like seeing the cadets break out into competitions to see how far they could push themselves in push-up contests when they had spare time. (Ok, yes I realize that doesn’t always happen and therefore we need mass teacup songs in formation to make sure they don’t get carried away with other independent activities.)

Also, when I was asked to gather cadets during cleanup and task them with moving gear and sweeping the hangar, I spent too much time wondering how to do that tasking. I didn’t jump into it. However, once I enlisted one cadet it started a chain reaction and soon everyone was helping. That was a simple little lesson in leadership … the worst-case scenario doesn’t always occur.

I was also impressed with Flight Staff. I don’t know whether they were happy or disappointed to have a flight of Senior Members, though the Flight Commander did say at the end that we were the easiest and most fun flights he’d ever had. Anyway, they were very professional and it was obvious that they didn’t like screwing around (as opposed to decent fun). They were also always very friendly and our Flight Sergeant was always trying to anticipate the needs of the next activity by researching, asking questions, and gathering equipment and information.

This was my first experience with the Cadets of Minnesota Wing and it was a wonderful experience.

– Michael Delk, 1st Lt, MN104