My wife and I will celebrate our tenth anniversary (my god she must be a patient woman!) on the 27th of August 2009, the day Mars will be largest to our eyes. Hotcha! (I’ll write a post about this astronomical phenomenon soon.) (No- wait! I’d better write about it now. See the mea culpa at the bottom of the post )
We seem to be a astronomically significant couple. I proposed to her on a Double Blue Moon (the second blue moon in one calendar year). Those happen about 4 times a century. I just googled them, and there doesn’t seem to be a name for that astronomical phenomenon (I mean, “Double Blue Moon” doesn’t seem as romantic as “Harvest Moon”, “Full Wolf Moon”, or “Full Beaver Moon? (hmmmm…)) I thought I’d christen it myself.
From now on the “Double Blue Moon” shall be known as the “Foley Moon“ (why not?)
Hotcha!
What is a Blue Moon?
There are several definitions for a blue moon.
In general, a full moon that does not occur at an expected interval (say, more than twelve per year, or three per season) was considered a “blue moon.”
Another definition is for when the moon (even if it isn’t necessarily a full moon) actually appears to be blue. This can happen because of smoke particles in the air. Apparently this was the case after the eruption of the volcano at Krakatoa in the 1800s, and reportedly at least one time since, in 1950 in Sweden and Canada.
If two full moons occur in any calendar month, the second is called a blue moon.
The above definition is the most frequently used, contemporary one. The two contemporary definitions of blue moon, the second full moon in a calendar month (the astronomical definition) and something that rarely happens, are not equivalent. Astronomical blue moons happen fairly often, once every 2.5 years on average.
There are 29.53 days between any two Full Moons (Moon’s synodic period) . There are 365.25636 days in the year. That equals 12.37 Lunar Months. The extra 10 or so days allows for an occasional extra Full Moon, because after about 2.7 years that builds up to over one extra period of more than 29.53 days. Here is a list of Blue Moons for the first half of the 21st century.
- November 30 2001
- July 31 2004
- June 30 2007
- December 31 2009
- August 31 2012
- July 31 2015
- January 31 2018
- March 31 2018
- October 31 2020
- August 31 2022
- May 31 2026
- December 31 2028
- September 30 2031
- July 31 2034
- January 31 2037
- October 31 2039
- August 31 2042
- May 30 2045
- January 31 2048
- September 30 2050
The phrase, “Once in a Blue Moon”
According to Erich Weissman’s World of Astronomy:
The earliest use of “blue moon” meant an obvious absurdity which everyone knew never happened. However, the moon does occasionally turn blue as a result of smoke from forest fires or particles from a volcanic eruption. Since these blue-looking moons were rare but did happen from time to time, the phrase “once in a blue moon” was coined, meaning that an event is unusual, but can happen occasionally (Kibbey).
According to this article about blue moons:
The recent use of the word Blue Moon to describe the second full moon of a month can be traced to J. Hugh Pruett’s April, 1946, article in Sky and Telescope magazine entitled Once in A Blue Moon.
In his article, Hugh mentioned an old Maine Farmers’ Almanac for the year 1937. He wrote, “In effect . . . at one time the various full moons of the year were given names according to the order in which they occurred — provided there was only one per month. These names were as follows: Moon after Yule, Wolf Moon, Lenten Moon, Egg Moon, Milk Moon, Flower Moon, Hay Moon, Grain Moon, Fruit Moon, Harvest Moon, Hunters’ Moon and Moon Before Yule. But seven times in 19 years there were — and still are — 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon, and was considered unlucky and a real nuisance as it occurred at various times of the year and upset scheduling of church festivals.”
You can read the full story of the origin of the phrase “Once in a Blue Moon” here.
What is a Double Blue Moon?
If two blue moons occur in the same calendar year, the second blue moon is a “double blue moon.”
There are approximately 4 Double Blue Moons in each century. Can you figure out why?
There were double full moons in 1961 and 1999, and the next ones will be in 2018 and 2037.
The song, “Blue Moon”
As you can imagine, “Blue Moon” is “our song.”
Blue Moon
Now Im no longer alone
Without a dream in my heart
Without a love of my own
- Rogers and Hart
This song was first recorded in 1934, but was unreleased. Since then it appeared in several movies, and was covered by many artists, the most famous of which were:
Ella Fitzgerald with Tony Bennet, Elvis Presley, Frank Sinatra, Bob Dylan, The Marcels, Sam Cooke, Frankie Laine, Louis Armstrong, Dean Martin, Django Reinhardt, The Supremes, Mel Torme, The Ventures, Sha Na Na, Dizzie Gillespie, and my personal favorite version by Cybill Shephard (although as a Doo-Wop fan, the Marcels come in a close second – the “double” blue moon!)
References:
http://www.farmersalmanac.com/full-moon-names
http://science.nasa.gov/current/event/ast30mar99_1.htm
http://scienceworld.wolfram.com/astronomy/BlueMoon.html
Do the math:
Is there a month in which a blue moon cannot occur?
Hint: The Moon’s synodic period is 29.531 days.
Mea culpa:
Ever wonder what happens when a know-it-all amateur recreational-mathematician dives in out of his league? Well, you don’t have to wonder anymore. I goofed up, big. Normally I am a big skeptic, but I guess I didn’t have my skeptic’s hat on when my science-teacher friend sent me the viral e-mail that’s been going around about Mars and the Moon.
It turns out that it’s a hoax. A very astute reader (see the comment below) sent me the heads-up on it. Sorry about that, dear readers. Please pardon me while I wipe the egg off my face. For the skinny on the scam, see http://www.universetoday.com/2006/07/27/no-mars-wont-look-as-big-as-the-moon-in-august/
The lesson? Don’t assume a damned thing until you’ve checked it with snopes.com (or your friendly, neighborhood astronomy teacher.) Thanks, Mike!
Oops. Mars will not be close on 27 August this year (as it was in 2003) because Mars actually follows a 26-month synodic cycle; the next close-approach of Mars will be in late January 2010.
But don’t take my word for it: http://www.snopes.com/science/.....htmars.asp
What is the exact time that the moon will be full on December 31, 2009?
Mary,
That’s an interesting question.
The short answer is of course, “all night.”
In general, we break up the phases of the moon into discrete parts. When we speak of a quarter moon, half Moon, or a full moon, we generally mean that night, or nights on which the moon appears to be at those fractions.
The long answer is, “I don’t know.” That’s just part of the long answer really. The reason for that is, that the very instant the moon is precisely full from our vantage point here on earth, is beyond my ability to reckon. I imagine there are some astronomy sites that will be able to give you a more precise answer than simply,” all night of the 31st.”
The reason for this discrepancy between the short and the long answer, is that the human eye normally cannot detect, nor does the human mind discriminate, very accurately on the fly.
It’s sort of like saying that someone is 25 years old. Of course he’s not exactly 25 years old, unless you’re saying that exactly 25 years to the month, week, day, hour, minute, second, and instant the person was born, 25, years later.
So if somebody were to ask you when you are going to be 25, and you are only 18 years, three months and two days old now, you could say “in seven years,” and you would be right, but not quite as accurate as you could be. It’s just, as they say, “close enough for government work.”
I’m not exactly sure if you are aware that we commonly consider the full moon to be occurring the entire night, or not. If you weren’t, then the short answer is the answer you want. If you are, then you’ll need somebody who is much more informed about such things than me to give you that information. I googled it, but could not find it. Although I must admit, I didn’t spend much time googling it.
To be perfectly accurate, you’d also have to know exactly where on the earth you would be viewing the moon from in order to be able to compute the precise time. I don’t know if this is feasible for anyone other than a researcher to be doing, although it is an interesting question. It’s sort of like asking what precise time will sun-up occur. You’d have to know where you were standing on the earth in order to reckon that.
I hope I have been able to help you. If another reader knows more about this than I do (which is quite likely) I’d appreciate his or her comments.
All the best,
Brian (a.k.a. Professor Homunculus)
One could contact the local TV news station and ask when is the exact time for the “moonrise” & “Moonset”…armed with this information – one could calculate the exact middle “phase” of the process….thus you would have the exact time (in your locale) for the moon’s “fullest” position!!!
What exactly does the term Wolf Moon mean?? It seemed as if there were two full moons this month (January 2010) and the second one was bright and irritating. Irritating in the sense that I couldn’t decide if the light through my window was the moon or the sun. My husband searched the web and uncovered the term wolf moon. Geoff’s research indicated that the moon was closer to the earth than any other time during the coming year. Do you think the term has derived its meaning from the very fact that the moon’s nearness draws us to it, causing the general populace and the tides to surge in response to its effects? Practically baying at the moon, like a wolf??
According to The Farmers Almanac:
“Full Wolf Moon – January Amid the cold and deep snows of midwinter, the wolf packs howled hungrily outside Indian villages. Thus, the name for January’s full Moon.”
As far as why the moon appeared bigger the Jan 29, 2010, the basic answer is that Geoff is right. The moon was at it’s perigee. You can read about it at this excellent article.
Now to what may be the most important issue: I haven’t noticed any humans other than adolescents just being silly (I remember being one of them, vaguely) baying at the moon. Not that my noticing or not makes any difference. And that is my point – what we think we notice, and what has any truth to each it, are not necessarily equivalent subsets of each other.
In other words, anecdotal evidence is seldom true evidence. The idea that the “pull of the moon” makes us crazy is just a myth. Study after study has debunked it, but somehow it still comes up, like astrology or even phrenology.
Actually, even wolves don’t howl because of the full moon. Check it out at the end of this fascinating article.
It’s a nice myth, though. Kind of romantic, but just untrue. My friend told me, and he ought to know, he’s a werewolf.
By the way, there was only one full moon this Jan. There was one on Dec. 31, 2009, though. The reason they don’t occur every 28 days is posted in the link above in the section Do the Math.
Thanks for your interesting question. I’ll bet a lot of people were wondering the same things.
I’m going to bookmark this blogg on Digg to get more traffic for you.