Blue moon
31/07/15 05:25
OK, it actually isn’t that rare. We use the phrase, “once in a blue moon,” to describe a rare event - some use it to refer to once-in-a-lifetime events. But blue moons aren’t all that rare. Tonight offers a good chance for a great view of a full moon around here and we call it a blue moon. The common contemporary definition of a blue moon is the second full moon in the same calendar month. Since full moons occur every 29.5 days, the position of the full moon on the calendar makes it possible for a blue moon to occur only when the first full moon of the month occurs early. It is, of course, slightly more common in months with 31 days, but possible in every month except February, where it can occur only in leap year. Over the next 20 years there will be about 15 blue moons. There was one last year. There is one today. There will be one in 2016, but none in 2017. In 1999, there were two blue moons in the same year. That phenomenon occurs about every 19 years, usually when there is a blue moon in January. If the second blue moon falls late enough in January and it isn’t a leap year, February can skip a full moon entirely and March will end up with a blue moon as well.
All of that, confusing as it may seem, is only the tip of the iceberg, really, because two full moons in the same month is the modern definition of a blue moon. There is an older definition that is more complex. According to the Farmer’s Almanac, the older definition goes like this: a blue moon is the third full moon in a season that has four full moons. That would make the full moon in May of next year a blue moon by the old definition.
And why would we want to identify the third full moon in a season with four full moons? That’s where Christian theology enters into the definition. At least Christian tradition, to be more accurate.
Stick with me for a moment.
Some years have an extra full moon - 13 instead of 12. Our common calendar is based on the movement of the earth around the sun. That is one way to measure time. The ancients, however, frequently measured time by the movement of the moon around the earth, counting the full moons. This “lunar calendar” differs from the so-called solar calendar. In a lunar calendar each month is 29.5 days. Since 12 months of 29.5 day months results in 354 days and a solar year is 365 days, the lunar calendar gets “ahead” of the solar calendar. If you follow a strictly lunar calendar, then, the dates of holidays appear in different seasons in different years, as is the case with the Muslim calendar of holidays.
The Christian calendar, however, seeks to maintain the same seasons for its holidays while using the cycles of the moon to measure the exact days. Easter always occurs in the spring, for example, but not on a fixed day. Easter can occur in March or April. The Paschal Moon - critical for determining the date of Easter - is one of 12 named moons in the Jewish calendar. In years when there are 13 full moons, there is no name for the 13th moon. The 13th moon gained the name “blue moon.” However, the holidays won’t line up with the seasons if the blue moon is always the last full moon of the year. Thus the practice of naming the third moon “blue” when the season has four full moons evolved.
If you are fully confused by now, no worries! So am I. I pretty much use the modern definition of the second full moon in a month for blue moon and I use the Internet or the calendar printed by the church to discern the date of Easter each year.
As a preacher, I’ve grown to appreciate the quirky calendar that give us liturgical seasons that vary in length. Some years Epiphany is short, other years it is long. The length of Pentecost is changed to offset that difference. That means that while the order of the seasons of our faith remains constant, the emphasis shifts from year to year. The number of sermons preached in a given season affects how much we think about specific topics or themes of Christianity. Since our faith is filled with surprises and fresh insights, the variability helps us to be open to newness within the structure of the year.
And, of course, the color of the moon tonight won’t be blue. Well, it is possible for it to appear a bit blue for us if there is enough smoke from the fires out west and up north to make the sky hazy. If so, it won’t appear blue at moonrise. When the moon is close to the horizon, it appears in the red-orange end of the color spectrum, for the same reason that sunrises and sunsets tend toward those colors.
Ash from volcanoes can also make the moon appear to be blue in color.
The Oxford English Dictionary says that the term blue moon is actually more ancient than the modern alignment of the various calendars. The OED cites a 1528 proverb as a possible origin of the phrase: “If they say the moon is blue, we must believe that it is true.”
Now that proverb doesn’t make any sense at all to me. People often say things that aren’t true. I remember hearing, as a child, someone say that the moon was made out of green cheese. Even as a child, I couldn’t believe that! It isn’t green at all. And why cheese? My father loved cheese with green in it and they called that cheese “blue.” It is an acquired taste. I love it as an adult, but didn’t care for it as a child. When it came to cheese, I didn’t trust people’s color descriptions.
Ever since the astronauts walked on the dusty moon surface and brought back moon rocks to the earth, I’ve been pretty much convinced that the cheese part was as bogus as the color.
I think I’ll just look at the moon tonight. Blue or not it is beautiful.
All of that, confusing as it may seem, is only the tip of the iceberg, really, because two full moons in the same month is the modern definition of a blue moon. There is an older definition that is more complex. According to the Farmer’s Almanac, the older definition goes like this: a blue moon is the third full moon in a season that has four full moons. That would make the full moon in May of next year a blue moon by the old definition.
And why would we want to identify the third full moon in a season with four full moons? That’s where Christian theology enters into the definition. At least Christian tradition, to be more accurate.
Stick with me for a moment.
Some years have an extra full moon - 13 instead of 12. Our common calendar is based on the movement of the earth around the sun. That is one way to measure time. The ancients, however, frequently measured time by the movement of the moon around the earth, counting the full moons. This “lunar calendar” differs from the so-called solar calendar. In a lunar calendar each month is 29.5 days. Since 12 months of 29.5 day months results in 354 days and a solar year is 365 days, the lunar calendar gets “ahead” of the solar calendar. If you follow a strictly lunar calendar, then, the dates of holidays appear in different seasons in different years, as is the case with the Muslim calendar of holidays.
The Christian calendar, however, seeks to maintain the same seasons for its holidays while using the cycles of the moon to measure the exact days. Easter always occurs in the spring, for example, but not on a fixed day. Easter can occur in March or April. The Paschal Moon - critical for determining the date of Easter - is one of 12 named moons in the Jewish calendar. In years when there are 13 full moons, there is no name for the 13th moon. The 13th moon gained the name “blue moon.” However, the holidays won’t line up with the seasons if the blue moon is always the last full moon of the year. Thus the practice of naming the third moon “blue” when the season has four full moons evolved.
If you are fully confused by now, no worries! So am I. I pretty much use the modern definition of the second full moon in a month for blue moon and I use the Internet or the calendar printed by the church to discern the date of Easter each year.
As a preacher, I’ve grown to appreciate the quirky calendar that give us liturgical seasons that vary in length. Some years Epiphany is short, other years it is long. The length of Pentecost is changed to offset that difference. That means that while the order of the seasons of our faith remains constant, the emphasis shifts from year to year. The number of sermons preached in a given season affects how much we think about specific topics or themes of Christianity. Since our faith is filled with surprises and fresh insights, the variability helps us to be open to newness within the structure of the year.
And, of course, the color of the moon tonight won’t be blue. Well, it is possible for it to appear a bit blue for us if there is enough smoke from the fires out west and up north to make the sky hazy. If so, it won’t appear blue at moonrise. When the moon is close to the horizon, it appears in the red-orange end of the color spectrum, for the same reason that sunrises and sunsets tend toward those colors.
Ash from volcanoes can also make the moon appear to be blue in color.
The Oxford English Dictionary says that the term blue moon is actually more ancient than the modern alignment of the various calendars. The OED cites a 1528 proverb as a possible origin of the phrase: “If they say the moon is blue, we must believe that it is true.”
Now that proverb doesn’t make any sense at all to me. People often say things that aren’t true. I remember hearing, as a child, someone say that the moon was made out of green cheese. Even as a child, I couldn’t believe that! It isn’t green at all. And why cheese? My father loved cheese with green in it and they called that cheese “blue.” It is an acquired taste. I love it as an adult, but didn’t care for it as a child. When it came to cheese, I didn’t trust people’s color descriptions.
Ever since the astronauts walked on the dusty moon surface and brought back moon rocks to the earth, I’ve been pretty much convinced that the cheese part was as bogus as the color.
I think I’ll just look at the moon tonight. Blue or not it is beautiful.