Question

    When does a "blue moon" occur in the lunar calendar?

    A When the moon appears blue in color Correct Answer Incorrect Answer
    B When there are two full moons in a single month Correct Answer Incorrect Answer
    C When the moon is at its closest distance to Earth Correct Answer Incorrect Answer
    D When the moon is in a partial eclipse Correct Answer Incorrect Answer

    Solution

    Most of us know Blue Moons as the second full moon of a single calendar month. These happen a lot, too. The "blue moon" reference is applied to the third full moon in a season with four full moons, thus correcting the timing of the last month of a season that would have otherwise been expected too early. This happens every two to three years (seven times in the Metonic cycle of 19 years).

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