Thursday, May 31, 2007

TT #42: once in a blue moon

Thirteen things about the blue moon

A blue moon is a second full moon to occur in a single calendar month.
"Once in a blue moon" means not very often.

  • Some sources say that in 2007, there is a blue moon in June. Others say that the blue moon actually occurs in May. Who is right? Well, you could see a blue moon in May, June or even July, but it depends where in the world you live. Look here to find out.

  • There are historical examples of the moon actually turning blue. When the Indonesian volcano Krakatoa exploded in 1883, its dust turned sunsets green and the moon blue all around the world for the best part of two years. In 1927, the Indian monsoons were late arriving and the extra-long dry season blew up enough dust for a blue moon. And moons in northeastern North America turned blue in 1951 when huge forest fires in western Canada threw smoke particles up into the sky.

  • The next month with two full moons (for both North America and Europe) is December 2009, and the next after that is August 2012.
  • Originally, the definition was different. Seasonal moon names are assigned near the spring equinox in accordance with the Christian ecclesiastical (church-) rules for determining the dates of Easter and Lent. The beginnings of summer, fall and winter are determined by the dynamical mean Sun. When a season contains four full moons, the third is called a blue moon. That's because only then will the names of the other full moons, such as the Moon Before Yule and the Moon After Yule, fall at the proper times relative to the solstices and equinoxes.

  • A blue moon happens about seven times every 19 years, roughly once every three years. The rare phenomenon of two blue moons occurring in the same year happens approximately once every 19 years (four or five times in a hundred years). It last happened in 1999, the next year of double blue moons is coming up in 2018.

  • Two full moons in one month may occur in any month out of the year except for February, which is shorter than the lunar cycle. Therefore, it is the only month in which it is possible for there to be no full moon, a phenomenon which goes hand-in-hand with the "double blue moon" (usually one in January and one in March).

  • "Blue moon" appears to have been a colloquial expression long before it developed its calendrical senses. According to the Oxford English Dictionary, the first reference to a blue moon comes from a proverb recorded in 1528: "If they say the moon is blue, We must believe that it is true." Saying the moon was blue was equivalent to saying the moon was made of green (or cream) cheese; it indicated an obvious absurdity. In the 19th century, the phrase "until a blue moon" developed, meaning "never." The phrase "once in a blue moon" today has come to mean "every now and then" or "rarely"—whether it gained that meaning through association with the lunar event remains uncertain.

  • A full moon on Halloween is always a blue moon, it happens three or four times per century. The 21st century has an unusually large number of Halloween blue moons, five or six to be exact (depending on where you live).

  • Double new moons also occur every two or three years, just like double full moons, but fewer people notice them. The second new moon is called the Black Moon, and any magic worked during that period is deemed to be especially powerful.

  • According to certain folklore, it is said that when there is a blue moon, the moon has a face and talks to the items in its moonlight.

  • Everybody knows the song "Blue Moon", recorded by many artists around the world. For example this video shows Dean Martin singing the song in his show.

  • A blue moon is a special time of magic. Wishes made during a blue moon are said to last until the next blue moon. It has an awesome power which can lend energy to any working done during this powerful phase.

  • If you want to know when there is (or was) a blue or black moon, use the Moon Calculator.

Sky & Telescope
Inconstant Moon
Earth & Sky

Am I the only one that can't visit the TT-site? Ever since last week Wednesday midnight I'm getting an error page. I can see part of the posts in my Google Reader though. It's quite annoying!


Links to other Thursday Thirteens!

Get the Thursday Thirteen code here!
The purpose of the meme is to get to know everyone who participates a little bit better every Thursday. Visiting fellow Thirteeners is encouraged! If you participate, leave the link to your Thirteen in others comments. It’s easy, and fun! Be sure to update your Thirteen with links that are left for you, as well! I will link to everyone who participates and leaves a link to their 13 things. Trackbacks, pings, comment links accepted!


  1. Hey pallie, thanks for the education on Blue Moons and like thanks so much for the great Dinoclip of Dino singin' "Blue Moon" where our Dino makes a blooper on the word whisper. Never was, never will be anyone as cool as the King of Cool. Oh, to return to the days when Dino walked the earth!

  2. This is great, Tink. Someone else did a TT 13 on the Blue Moon this week. What's fascinating is that you both covered the same subject yet introduced different points and information. I enjoyed both Blue Moon posts and need to check when it's going to happen in Japan!

    Happy TT!

  3. Very intersting Tink! I read there was a blue moon coming, but didn't know it had that much symbolism to it!

  4. A Blue Moon is a very cool phenomena. I just hope that the clouds clear away tonight so I can see it. Very interesting post!

  5. Oh, this is great info! Especially when we'll be having a blue moon now in June. Heh!

  6. Great list! Interesting, about the black moon; I had no idea!! (yeah..and Dino rocks!!!)

  7. This is going to sound silly, but the one thing I always remembered aboutt blue moon had to do with the Smurfs! It was something about Smurfette being born on a blue moon.

    I'm not going to figure out where she came from...

  8. This is the third blue moon TT I've seen this week; are you guys in synch, or what??? Best of all, I keep learning new things with each one (I did not know about Black Moons, for example. And it makes sense that magic would be more powerful during one).

    So cool to be learning so much about our sky...

    Happy TT, Tink!!!

  9. Didn't have any trouble visiting the TT site.

    Thanks for all the info about a blue moon.

  10. Fascinating TT Tink...I love learning more about the moon

  11. This is awesome, TINK!!

    I'm always enthralled with the moon, the energy, the mystery. And a blue moon...well, I can't wait to see it!

  12. Hi Tink!!!

    Another awesome TT list. I hadn't realized that there really aren't that many blue moons. I had thought they happened a couple times a i see how special they are. I am definately going to make a wish a special wish on this coming blue moon. I am fascinated by the sources of the phrase...thanks for checking that out. It's interesting that it doesn't seem to be the same usage as we use now.

    What a good topic!


  13. Hey...side note...I'm looking at both my caleder on the wall and on my computer...and neither records a full moon or the moons progress. This seems so weird, as I remember always having such. Whats even weirder is my wall calendar is a DaVinci Code'd think someone would have put a moon chart on this thing!

  14. Very cool--I love the facts!

  15. AND blue moons are when I clean my closets. :-)

  16. I'd heard some of this, but a lot is new. I'm surprised that "blue moon" was a colloquial expression first--I'd have thought it would be the other way around.

    Fun & informative, as usual--thanks!

  17. I didn't know magic lasted from one blue moon to the next...hmm...That gives me some ideas! Thanks for all the blue moon info!

  18. WOW! I'm going to have my kids read this. (I home school, I'll make this lesson for the day lol)

    I'm fascinated by the moon and very excited about the blue moon as is my youngest!

    Great list. :)

  19. And all I can think of is the scene from Grease!

  20. Wow! What a great post! Thanks for visiting my Special K Family T13~

    Being An Air Force Wife

  21. Tink! Thanks for the great Blue Moon info - ours is May 31; I looked it up on the chart - AND for the fantastic Dean Martin video. As always, another fantastic list! Have a great weekend and Happy TTing...
    A Flyover Blog
    P.S. Thanks for dropping by!

  22. I stopped in my tracks last night at the beauty of that blue moon. There was a smattering of cloud to make it even more shivery.

    Thanks for a fascinating TT!

  23. Hi Tink - very timely TT! I love learning new things...

  24. Anonymous31/5/07 18:17

    Neat-o! Another blue moon post, and different points in each of your lists. I'm learning a lot about blue moons! Fascinating stuff.

    Happy TT, and thanks for visiting my blog! :)

  25. Hey Tink, I heard about this blog and this particular entry from dino martin peters. This was an interesting article about Blue Moons. I definitely learned some new stuff. Also it was awesome to see the clip of Dino crooning "Blue Moon." I love his whipser goof. Thanks for sharing that with us.

  26. Wow, interesting. Is this why I had my monthly twice in May? My TT is up! Happy TT!

  27. Great list. Another person did their TT on blue moons too, so that makes three of us! :-)

    Thanks for stopping by mine.

  28. Looks like you put a lot of work into this weeks TT. Thanks for a great read.

  29. Love the thought of #!0!

  30. Wow, thats a lot of information!
    Great TT!
    Thanks for visiting my blog.

  31. Ow. My head hurts now! I went to that site you linked and got completely confused. If you see a blue moon and it is really blue, take pictures for me.

    Thanks for visiting my T13 #43 13 Bumper Stickers edition.

  32. Great TT, I have enjoyed these Blue Moon themed ones a lot. And I love the song =)

  33. I had no idea there was this much information on blue moons. Thanks for stopping by my TT.

  34. Great TT, Tink! Very cool. I don't think I'll get to see it. We are finally getting some rain here in Florida.

  35. Very cool info...I should make the kid read's educational.

    Thanks for stopping by.

  36. Excellent post on the Blue Moon! Happy TT!

  37. Cool list. I didn't know about the black moons either, might be able to use that in my WIP. Happy TT.

  38. Tink, very interesting post. Thanks for stopping by!

  39. Way cool Tink. Thanks for the great info.

    & thanks for the read


  40. i love astronomical trivia. thanx for the links to your sources too. can't wait to check them out.

    i played that silly Google game for my TT: 13 Google thinks Joy needs.

  41. That's the seconf T13 post about blue moons I read today. I agree with Gabriella, you both did it differently. Great post.

  42. A very nice and informative list as always.
    I never knew that the moon could actually seem blue, I've only seen it glow red-ish, orange and yellow so far. But blue would be great. In a very strange way. ;o)

  43. Interesting facts about the moon. I often look at the moon but have to knowledge of it. Thanks.

  44. I knew this month had two full moons and the second was referred to as a blue moon but thanks to you I now know far more.
    Thank you so much for sharing.
    I may have to do something witchy this full moon eve.

    Be well and enjoy the day.

  45. that is so interesting! I love this information. :)

    Happy TT (a little bit late...yesterday kind of exploded around here!)

  46. Interesting post! Maybe your readers would enjoy this article by folklorist Philip Hiscock: Folklore of the Blue Moon


    Deborah Byrd
    Earth & Sky

  47. Thanks for the knowledge. Unfortunately I couldn't find my Country so I guess we won't have a blue moon.
    Thanks for the visit.

  48. I also read the other blue moon post, but agree that you covered it in a different way. Happy TT.


I'm really sorry I had to enable comment & word moderation. Loads of spam comments spoiled the free commenting, but please... don't let it stop you. I love every non-spam comment!
Thanks for visiting.
Love, Tink