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July Is A “Blue Moon” Month!
by Joe Rao | Monday, July 6th, 2015 | From: Astronomy, Featured
The month of July brings us not one, but two full Moons. The first kicked off last week with the full Buck Moon on July 1st, and will be followed by a second on Friday, July 31.
Some almanacs and calendars assert that when two full Moons occur within a calendar month, the second full Moon is called a “Blue Moon.” The full (blue) Moon on that last Friday night in July will likely look no different than any other full Moon, and most likely will not look blue in color. However, the Moon can change color in certain conditions.
After forest fires or volcanic eruptions, the Moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth’s atmosphere, can sometimes make it appear bluish. Smoke from widespread forest fire activity in western Canada created a true Blue Moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991, there were reports of Blue Moons (and even blue suns) worldwide.
Origin of the Term
The phrase “once in a blue moon” was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full Moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 2.66 years. And in the year 1999, it occurred twice in a span of just three months.
For the longest time no one seemed to have a clue as to where the “Blue Moon Rule” originated. Many years ago in the pages of Natural History magazine, I speculated that the rule might have evolved out of the fact that the word belewe came from the Old English, meaning, “to betray.” “Perhaps,” I suggested, “the second full Moon is belewe because it betrays the usual perception of one full Moon per month.” But as innovative as my explanation was, it turned out to be completely wrong.
More Mistakes
It was not until that “double Blue Moon year” of 1999 that the origin of the calendrical term “Blue Moon” was at long last discovered. It was during the time frame from 1932 through 1957 that the Maine Farmers’ Almanac – not to be confused with our own Farmers’ Almanac which is published in Lewiston, Maine – suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a Blue Moon.
But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that’s now popularly accepted as the definition of a Blue Moon.
This time around, the Moon will turn full on July 31 at 6:43 a.m. Eastern Daylight Time (3:43 a.m. Pacific Standard Time), making it a Blue Moon.
Blue Moon/New Moon
While we’ve assigned the name Blue Moon to the second full Moon of the month, it seems that we have no such name for the second new Moon of the month. Nonetheless, these opposing phases seem to be connected with each other. For if two new Moons occur within a specific month, then in most cases, four years later, two full Moons will also occur in that very same month.
As an example, there were two new moons in July 2011. Now, four years later, July 2015 will be graced with two full moons.
The next time we will see two full Moons in a single month will come in 2018 – twice! In January and again in March! Another “double Blue Moon year” just like in 1999. The reason for this is a cycle discovered by the Greek astronomer Meton of Athens, who around 440 B.C., noticed that 235 lunar months made up almost exactly 19 solar years.
Or, in other words, if a particular phase of the Moon occurs on a certain date, then, more often than not, that same lunar phase will occur on the same date 19 years later. This has been referred to as the Metonic Cycle.
And if you still have a calendar leftover from last year, check the month of July. You’ll find that there were two new Moons in January and March!
http://farmersalmanac.com/astronomy/2015/07/06/july-is-a-blue-moon-month/
by Joe Rao | Monday, July 6th, 2015 | From: Astronomy, Featured
The month of July brings us not one, but two full Moons. The first kicked off last week with the full Buck Moon on July 1st, and will be followed by a second on Friday, July 31.
Some almanacs and calendars assert that when two full Moons occur within a calendar month, the second full Moon is called a “Blue Moon.” The full (blue) Moon on that last Friday night in July will likely look no different than any other full Moon, and most likely will not look blue in color. However, the Moon can change color in certain conditions.
After forest fires or volcanic eruptions, the Moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth’s atmosphere, can sometimes make it appear bluish. Smoke from widespread forest fire activity in western Canada created a true Blue Moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991, there were reports of Blue Moons (and even blue suns) worldwide.
Origin of the Term
The phrase “once in a blue moon” was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full Moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 2.66 years. And in the year 1999, it occurred twice in a span of just three months.
For the longest time no one seemed to have a clue as to where the “Blue Moon Rule” originated. Many years ago in the pages of Natural History magazine, I speculated that the rule might have evolved out of the fact that the word belewe came from the Old English, meaning, “to betray.” “Perhaps,” I suggested, “the second full Moon is belewe because it betrays the usual perception of one full Moon per month.” But as innovative as my explanation was, it turned out to be completely wrong.
More Mistakes
It was not until that “double Blue Moon year” of 1999 that the origin of the calendrical term “Blue Moon” was at long last discovered. It was during the time frame from 1932 through 1957 that the Maine Farmers’ Almanac – not to be confused with our own Farmers’ Almanac which is published in Lewiston, Maine – suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a Blue Moon.
But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that’s now popularly accepted as the definition of a Blue Moon.
This time around, the Moon will turn full on July 31 at 6:43 a.m. Eastern Daylight Time (3:43 a.m. Pacific Standard Time), making it a Blue Moon.
Blue Moon/New Moon
While we’ve assigned the name Blue Moon to the second full Moon of the month, it seems that we have no such name for the second new Moon of the month. Nonetheless, these opposing phases seem to be connected with each other. For if two new Moons occur within a specific month, then in most cases, four years later, two full Moons will also occur in that very same month.
As an example, there were two new moons in July 2011. Now, four years later, July 2015 will be graced with two full moons.
The next time we will see two full Moons in a single month will come in 2018 – twice! In January and again in March! Another “double Blue Moon year” just like in 1999. The reason for this is a cycle discovered by the Greek astronomer Meton of Athens, who around 440 B.C., noticed that 235 lunar months made up almost exactly 19 solar years.
Or, in other words, if a particular phase of the Moon occurs on a certain date, then, more often than not, that same lunar phase will occur on the same date 19 years later. This has been referred to as the Metonic Cycle.
And if you still have a calendar leftover from last year, check the month of July. You’ll find that there were two new Moons in January and March!
http://farmersalmanac.com/astronomy/2015/07/06/july-is-a-blue-moon-month/
