Q&A: What's the origin of 'blue moon'?

It's once in a blue moon

What is the origin of the term "blue moon"? It is used when more than one full moon occurs in a month, as in this month, when there was one full moon Dec. 2 and another is Dec. 31.

The moon typically takes 29 to 29 1/2 days to revolve around the Earth, said Angela Sarrazine, an astronomer at Fernbank Science Center in Atlanta. Since most months are 30 to 31 days long, about every 2 to 2 1/2 years, a month will have two full moons, she said.

The second full moon on Dec. 31 will be called a blue moon, the term used in modern folklore to describe two full moons within one month, she said. A NASA report links the term to the 1883 explosion of the Indonesian volcano Krakatau, when ash rose to the top of the Earth's atmosphere, making the moon appear blue.

Sky & Telescope magazine links the term to an article in a 1946 issue that erroneously used data from the Maine Farmers' Almanac that referred to a blue moon occurring a certain number of times per season, not a calendar year.

Back for more 'Treatment'

Please tell me when I can expect that wonderful, intelligent show In Treatment to return.

The HBO drama with Gabriel Byrne will begin production in early 2010 for telecast later in the year.

Off the World's Fair circuit

The United States has hosted a fair share of World's Fairs (Expos), but I don't think we've done so for many years. Do we have any plans to host any and, if not, why?

The United States has hosted 17 World's Fairs, with its last one in 1984 in New Orleans, according to the International Trade Administration. One issue is that the country is no longer a member of the Paris-based Bureau International des Expositions, according to the Wall Street Journal.

The paper says a country must belong to the 154-nation treaty organization to host an officially sanctioned fair. But private funds were raised for a $61 million U.S. pavilion at the Shanghai Expo 2010.

Fictional, but familiar names

I have been watching the series Mercy, about a hospital and its people, and the series Three Rivers, also about a hospital and its people. Are there really a Mercy Hospital and a Three Rivers Hospital?

There are hospitals with those names, including a Three Rivers Hospital in Tennessee, a Three Rivers Medical Center in Kentucky and Mercy hospitals in Miami and Maine. But the institutions on the TV shows are fictional, with NBC's Mercy hospital in Jersey City, N.J., and CBS's Three Rivers in Pittsburgh.

Q&A: What's the origin of 'blue moon'? 12/28/09 [Last modified: Monday, December 28, 2009 4:01pm]

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