天文学家表示，12月31日晚上，北美、欧洲和非洲国家的人们将看到本月的第二轮满月，即人们所说的“蓝月”，而东半球的人们则有望观赏到本年度最后一次月偏食。据科学家介绍，在天文历法中，当一个月出现两次满月时，第二个满月就被赋予一个充满神秘浪漫色彩的名字——“蓝月”（Blue Moon）。由于月运周期（月亮绕地球一周）是29.5天，因此，大约每30个月就会出现一轮“蓝月”。据悉，上一次出现“蓝月”是在2007年的5月，而此次新年“蓝月”则更为罕见，科学家称每19年我们才有机会在“蓝月”的映照下迎来新的一年，下一次可就要等到2028年了。

Once in a blue moon there is one on New Year's Eve. Revelers ringing in 2010 will be treated to a so-called blue moon.

Once in a blue moon千载难逢，极为罕见 there is one on New Year's Eve. Revelers ringing in 2010 will be treated to a so-called blue moon. According to popular definition, a blue moon is the second full moon in a month. But don't expect it to be blue - the name has nothing to do with the color of our closest celestial天上的，天空的 neighbor.

A full moon occurred on December 2. It will appear again on Thursday in time for the New Year's countdown.

"If you're in Times Square, you'll see the full moon right above you. It's going to be that brilliant," said Jack² Horkheimer, director emeritus名誉退休的 of the Miami Space Transit⁴ Planetarium⁵ and host of a weekly astronomy TV show.

The New Year's Eve blue moon will be visible in the United States, Canada, Europe, South America and Africa. For partygoers社交聚会常客 in Australia and Asia, the full moon does not show up until New Year's Day, making January a blue moon month for them.

However, the Eastern Hemisphere can celebrate with a partial lunar eclipse月偏食 on New Year's Eve when part of the moon enters the Earth's shadow. The eclipse will not be visible in the Americas.

A full moon occurs every 29.5 days, and most years have 12. On average, an extra full moon in a month - a blue moon - occurs every 2.5 years. The last time there was a lunar double take was in May 2007. New Year's Eve blue moons are rarer, occurring every 19 years. The last time was in 1990; the next one won't come again until 2028.

Blue moons have no astronomical天文的 significance, said Greg Laughlin, an astronomer⁷ at the University of California, Santa Cruz.

"`Blue moon' is just a name in the same sense as a `hunter's moon' or a `harvest moon秋分前后的满月,'" Laughlin said in an e-mail.

The popular definition of blue moon came about after a writer for Sky & Telescope magazine in 1946 misinterpreted the Maine Farmer's Almanac and labeled a blue moon as the second full moon in a month. In fact, the almanac年鉴，年历 defined a blue moon as the third full moon in a season with four full moons, not the usual three.

Though Sky & Telescope corrected the error decades later, the definition caught on. For purists纯化论者, however, this New Year's Eve full moon doesn't even qualify as a blue moon. It's just the first full moon of the winter season.

In a tongue-in-cheek essay posted on the magazine's Web site this week, senior contributing editor Kelly Beatty wrote: "If skies are clear when I'm out celebrating, I'll take a peek⁸ at偷看一下 that brilliant orb天体，球 as it rises over the Boston skyline地平线 to see if it's an icy shade of blue. Or maybe I'll just howl."