"Blue Moon" Appears in Sky Saturday Night 154
ArbiterOne writes "Tonight a rare spectacle can be seen: the second full moon in a month, which is sometimes called the "blue moon", according to CNN. Don't be disappointed if it isn't actually blue, though; the blueness is caused by increased density of smoke or ash in the air, such as after a volcanic eruption."
Not all that rare (Score:5, Interesting)
Re:Not all that rare (Score:3, Interesting)
There are approximately 13 lunar cycles in a year, and 12 months. Simple math should be able to tell you that there must be a blue moon on average at least once a year--rarely two, and rarely none. In fact, over the next 20 years, 17 will have blue moons [infoplease.com].
That's about every 1.2 years.
Re:Not all that rare (Score:4, Informative)
The 17 blue moons in 20 years is due to two different definitions of what constitutes a blue moon. So, blue moons are twice as common, because there are two different ways to define what a blue moon is!
Re:Not all that rare (Score:3, Informative)
I don't know how infoplease.com counted blue moons to get 17 in the next twenty years, unless it was counting both the 2nd-in-a-month and the 4th-in-a-season varieties. Ask this blue moon calculator [obliquity.com] to list the blue moons between 2004 and 2024, and it lists nine of them (of the 2nd-in-a-month kind).
That's about every 2.2 years.
Re:Not all that rare (Score:2)
yes, but only if you enter the correct numbers. Or even nearly correct numbers. 29.5 springs to mind.
Re:Not all that rare (Score:1)
There actually were 17 blue moons total with both definitions of a blue moon: about the same number of each kind [infoplease.com] (probably 8 of one and 9 of another).
The "13 lunar cycles in a year" was just a common (and, in my defense, approximately correct) approximation. But that
Still, I wouldn't call it rare.
Re:Not all that rare (Score:4, Funny)
Re:Not all that rare (Score:2)
Re:Not all that rare (Score:1, Funny)
1 * once in a blue moon = 1.16699016 × 10-08 hertz [google.com]
1 / frequency = time.
Re:Not all that rare (Score:2, Informative)
ARgh! (Score:5, Funny)
Rare? (Score:5, Interesting)
The phrase "Once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, perhaps even rare. Yet, to have two full Moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 32 months. And in the year 1999 it actually occurred twice in three months.
Re:Rare? (Score:5, Informative)
I heard that the adoption of the term blue moon in modern usage actually stems from a misappropriation of the term from some Native American tribe (around the time frame you mention, early 19th C). The term, as far as my uninformed and caffeine-addled mind can conjure at the moment, originally referred to an occurrence of a particular full moon that occurred during the three-month harvest season; specifically, when four moons occurred during this three month season, the third of the sequence was called a "blue moon". (The Wikipedia entry [wikipedia.org] seems to make reference to this--see the second entry--but I can't find anything specific on it. Also, it doesn't seem to mention the "harvest" season, just any season, which is not what I heard from my unreliable source.)
This is why our concept of blue moon as the second in a month doesn't seem to make sense in terms of rarity...it's not that rare. It makes a bit more sense if we consider how often four moons occur during the three month harvest season. That was probably quite a bit more rare.
Re:Rare? (Score:5, Informative)
Re:Rare? (Score:5, Informative)
Re:Rare? (Score:1)
It was particularly interesting to me since I just saw Tom Skilling (a Chicago television meteorologist) describe how two blue moons in a month was the wrong definition and four in a season is correct. He even mentioned the 1946 Sky and Telescope article as the reason for the confusion.
I suspect he read this later Sky and Telescope article, but reading it I realize that even his "correction" is bit of an over-simplification.
Re:Rare? (Score:2)
I l;earned that in the early 70s.
Doesn't mean it's correct, just what I had learned.
I stopped playing trivial persuit what that said that 'Reno' is the capital of Nevada.
Re:Rare? (Score:2, Interesting)
Re:Rare? (Score:1)
Re:Rare? (Score:2)
Re:Rare? (Score:1)
Re:Rare? (Score:1)
Re:Rare? (Score:1, Interesting)
Re:Rare? (Score:1)
Various definitions (Score:2)
The definition of two full moons in a month is now "correct" due to common usage. The urban legend has now become fact.
Apparently the earlier definition has to due with the oocurance of two full moons in a season. This ties in with the supposed American indian names from the colonial era [farmersalmanac.com]. (note that the several thousand indian tribes would likely have a variety of names, IF they bothered to name them) This is actually more closely related to the Eur
How it spread ..... (Score:2)
Re:Rare? (Score:1)
Blue, where is that coming from? (Score:1)
This occured just 90 days after... (Score:1, Funny)
Once in a Blue Moon (Score:5, Funny)
Neat! Maybe that means my askslashdot submission will be accepted!
two full moons not originally "blue moon" (Score:1, Informative)
This is caused by ash or other particles in the air and the light reflecting from the moon is filtered through said air and is 'tinted'.
Every so often you see a "red moon" when the moon is close to the horizon. The refraction of the light traveling through the atmosphere makes it appear red.
At least the above was the original definition of "blue moon". Over the years the definition has change
Re:two full moons not originally "blue moon" (Score:2)
Rare? (Score:4, Interesting)
Re:Rare? (Score:4, Interesting)
(treating the months as independent of each other which obviously isn't the case but shouldn't affect the outcome)
It is not the case, it should affect the outcome, and it does. Using your figures and ignoring fractional days of a lunation, the day of the month on which a full moon occurs regresses 1-3 days each month, so if a "blue" moon occurs this month (in days 29-31) one can't occur next month (in days 26-28).
Less rare than you think... (Score:1)
There's no need to use probability here; enumeration will do quite nicely. It makes things a little easier if we approximate the lunar period as exactly 28 days and pretend that the year starts on March 1st (so that leap years are easier to deal with).
Starting at March 1st, there are 27 days on which the first full moon of the year can fall. It works out as: M
Re:Rare? (Score:2)
We see a full moon every 29.5 days on average. See this page [wolfram.com] for the computation and exact value of the synodic period.
The odds (Score:2)
Re:Rare? (Score:2)
Except that since we have a full moon at least once a month (ok, except February, maybe), we must accept a margin of error of 12 hours.
Except that if we have a margin of error of 12 hours, (sufficiently) full moons occur two nights running every other month.
Except that if full moons can occur two nights running and then another 29.5 days after the day between those two nights, three full months p
Dark Side (Score:2)
Re:Dark Side (Score:1)
Re:Dark Side (Score:2)
Far side. Far Side of the moon. There is no permenantly dark side. Daylight lasts 2 weeks.
Still, funny post.
The Marcels (Score:1, Informative)
Without a dream in my heart
Without a love of my own
Blue Moon, you knew just what I was there for
You heard me saying a prayer for
Someone I really could care for
And then there suddenly appeared before me
The only one my arms will ever hold
I heard somebody whisper, "Please adore me"
And when I looked, the moon had turned to gold
Blue Moon, now I'm no longer alone
Without a dream in my heart
Without a love of my own
Very very rare (Score:5, Funny)
Re:Very very rare (Score:1)
- This is my first post
Re:Very very rare (Score:1)
The article is about blue moons, not full moons.
How rare? (Score:5, Insightful)
Re:How rare? (Score:3, Funny)
Canceling out? (Score:1)
interesting article about it in sky & telescop (Score:5, Informative)
From the article:
Black Moon is even more rare (Score:5, Interesting)
Re:Black Moon is even more rare (Score:5, Informative)
That would make it 2018 then? b.t.w. I don't think it's "usually february", I think it is always february. Every month other than february is guaranteed to be longer than the synodic period (about 29.5 days), so is guaranteed to contain a full moon. (apart from the month in which you change from julian to gregorian calendars...)
Re:Black Moon is even more rare (Score:3, Informative)
Of course, as someone pointed out, a "back moon" would imply
two blue moons in that year [blibbleblobble.co.uk]
So are we supposed to give them different names, or is it not possible to uniquely identify each moon in 2018? January Blue Moon and March Blue Moon or something?
And can you change when blue moons occur by selecting an appropriate timezone, or by changing to daylight-savings-time just before a full moon?
Re:Black Moon is even more rare (Score:2, Funny)
Re:Black Moon is even more rare (Score:2)
Re:Black Moon is even more rare (Score:2, Informative)
The last time there was no full moon in a month was February, 1999. The event was related to there being a Blue Moon in both January and March of that year.
Black Moon can also refer to two new moons in one month. The last time it happened was May, 2003. The next time will be December, 2005.
And let us not forget the Cheshire Moon. This name refers to a new or crescent moon where the line of the crescent looks like a smile or bowl instead of the typical "C" shape.
The explanation given here: [usatoday.com]
Re:Black Moon is even more rare (Score:1, Informative)
Blue moon explained (Score:3, Informative)
Re:Blue moon explained (Score:2)
Not Blue and Not Really a Blue Moon (Score:1)
"Only once in a blue moon is there controversy over exactly what constitutes a blue moon. But it's not a blue moon in the strict definition of the 19th Century Farmer's Almanac. According to the almanac, a true blue moon is the third full moon in a season that has four full moons. This also happens about every three years, but on a different cycle from the blue moon that occurs tonigh
Blue mooning (Score:2)
I swear I'm not making this up (Score:5, Funny)
Re:I swear I'm not making this up (Score:1)
Re:I swear I'm not making this up (Score:3, Funny)
Re:I swear I'm not making this up (Score:4, Funny)
That reminds me, in a roundabout way, of one of my favorite jokes. A college psychology professor decides to quiz his students on their sexual habits. He asks the class how many have had sex more than once in the past week? Several raise their hands. How about once in the past week? More hands go up. Once in the past two weeks? And so on ... after he has gotten to once every two months, he notices that everyone in the classroom has raised his or her hand, except for one guy sitting in the back. So he goes on:
"Three months". Nothing.
"Four months". Nope.
"Six months". Still nothing.
"One year?!".
Finally the guy in the back practically leaps out of his chair, raising his hand up high and bouncing up and down enthusiatically. The prof acknowledges him, and asks, "Well if you only get it once a year, why are you so happy?". The geeky guy smiles and says:
"'Cause tonight's the night!!"
P.S. If your wife wears glasses, may I recommend blue filters? :)
Re:I swear I'm not making this up (Score:2)
Ding ga dong ding... (Score:2)
Tim
P.S. The lyrics to that song (http://www.lyricsfind.com/m/marcels/best-of/blue
Ske & Telescope had an article about this... (Score:2, Interesting)
Science? (Score:4, Insightful)
Re:Science? (Score:1)
The moon is full every 28 days...
The number 28 appears to be a common confusion between the length of time between the same phase of the moon and the length of time it takes the moon to revolve once around the earth. . According to this [rhbnc.ac.uk] site:
It appears the moon is full about every 29 and half days, but your po
Re:Science? (Score:1)
Yes, it's called "astronomy."
"This is solely an artifact of our time measuring system."
A time measurement system based on the frequency vernal equinox, solar days and an attempted reconcilliation of the moon's orbit around the earth with the tropical year. Tidal forces between the earth, moon and sun keep everything related and fairly close to integer numbers.
"The moon is full every 28 days, but months are slightly longer than that."
Give it a few more million years. Fu
A new Smurf will be born tonight! (Score:2)
Mead moon and Nanci Griffith (Score:3, Informative)
The first moon in July is known as the "Mead Moon" [waningmoon.com].
A real nice song about the rarity of a Blue Moon is by Nanci Griffith [amazon.com].
I wonder how it affects global tides? (Score:1)
Re:I wonder how it affects global tides? (Score:1)
Re:I wonder how it affects global tides? (Score:5, Informative)
Re:I wonder how it affects global tides? (Score:1)
Re:I wonder how it affects global tides? (Score:3, Informative)
So what? (Score:5, Insightful)
Weird ring around the moon (Score:1)
Re:Weird ring around the moon (Score:2)
Have a beer for me:)
picture of actual BLUE moon (Score:1, Interesting)
Re:picture of actual BLUE moon (Score:1)
Beautiful! (Score:2)
/goes off to gloat over newest photo acquisition...
Once in a blue moon (Score:4, Funny)
"Sara, please cancel all my appointments; I'll be spending the day compiling E17 final and playing Duke Nukem Forever....."
-Chris
Still a chance for a `true' blue moon ... (Score:3, Informative)
Fortunately, there is a chance of a real blue moon [reuters.com] if you live near Anchorage, Alaska. Actually, it's not really a fortunate thing, because if this volcano does erupt and spew ash everywhere, it's a big mess. It mucks up your car, you don't want to breath it, it's almost caused airplanes to crash, etc. But it does have the possibility of causing the moon to appear truely blue.
Woohoo (Score:5, Funny)
Shameless plug (Score:1)
If you like classic 70's Stingrays or other classic chopper bicycles, check it out!
Do it today and feel extra special!
Great (Score:1)
What's that? Oh, I thought you said cows will be jumping over the moon. Wrong moon reference, sorry..
No, no; wrong reference entirely. (Score:2)
Admire it while it lasts.... (Score:2, Funny)
Blue photo at Astronomy Picture of the Day (Score:2, Informative)
Moon Phase indicator for KDE is pretty cool... (Score:1)
Written by Stephan Kulow.
Blue Moon (Score:2, Funny)
Don't need dupes anymore... (Score:1, Offtopic)
In this new category: IE exploits, IE patches, Firefox point-point releases, and PHP flamewars. I'm sure there's plenty of other things that can belong in this category...
This is wrong on so many levels (Score:1)
Let's not forget... (Score:2)
Boy am I sleepy.
Not for everyone tonight (Score:1)
Moo (Score:2)
The Gregorian and Julian calenders are solar based, however, being they have 31 days in some months, it is possible to have to full moon on both the first and 31st day of the month. That this is a rare occurence, is
Re:Global Warming... (Score:1, Funny)
It will cause the moon to obit the earth faster and produce more full moons.
Congrats, you may be the dumbest person ever on slashdot. And believe me, that's saying something.
Re:Global Warming... (Score:1)
BBC: Sunspots reaching 1,000-year high
A new analysis shows that the Sun is more active now than it has been at anytime in the previous 1,000 years.
Scientists based at the Institute for Astronomy in Zurich used ice cores from Greenland to construct a picture of our star's activity in the past.
They say that over the last century the number of sunspots rose at the same time that the Earth's climate became steadily warmer.