Essays: James Joyce

Showing posts with label James Joyce. Show all posts

Saturday, August 1, 2015

Lunation Calendar

There's usually one fully sunlit moon per month. Yesterday a second full moon appeared before July ceded our days to August.

Full Moons of July 2015

An occasional extra full moon is a function of the astronomical regularity of lunation and the papally decreed Gregorian Calendar introduced by Pope Gregory XIII in 1582.

Lunation - One lunar cycle with average duration of 29.53 days.

Our word moon comes from the Old English word mona.

"Even the word month is likely derived from the word moon and an Indo-European word, mê, which means to measure."
— Howard Markel

By measuring diurnality from the dark new moon to the sunlit full moon, our ancestors developed monthly calendars. Religious rituals like the Christian Easter were dutifully computed and observed around predictable lunar cycles. The Islamic calendar is purely lunar. The Christian Gregorian calendar is quasi-lunar.

Widely adopted, the Gregorian calendar has 12 months in a year. By comparison there are 12.37 lunations per year.

365.24 days/year ÷ 29.53 days/lunation = 12.37 lunations/year

The Gregorian calendar has exactly 12 months in a year, so an accumulation of .37 lunations occurs each Gregorian year. The accumulations of fractional lunations beyond the counting number 12, accounts for the occasional extra moon in a year.

An extra moon, whether considered over the time frame of a year, or over a season, or over a month, is colloquially called a blue moon to signify its rarity.

The blue moon isn't really an extra moon or blue in color, rather it follows as a side effect from a human construct of time - the Gregorian calendar.

Moon and Antelao

Image: Marcella Giulia

“Her antiquity in preceding and surviving succeeding tellurian generations: her nocturnal predominance: her satellitic dependence: her luminary reflection: her constancy under all her phases, rising and setting by her appointed times, waxing and waning: the forced invariability of her aspect: her indeterminate response to inaffirmative interrogation: her potency over effluent and refluent waters: her power to enamour, to mortify, to invest with beauty, to render insane, to incite to and aid delinquency: the tranquil inscrutability of her visage: the terribility of her isolated dominant resplendent propinquity: her omens of tempest and of calm: the stimulation of her light, her motion and her presence: the admonition of her craters, her arid seas, her silence: her splendour, when visible: her attraction, when invisible.”
― James Joyce, Ulysses

REFERENCES

Astronomy Photo of the Day: 7/31/15 — Antelao Moon, Posted By Jaime Trosperon 31 July 2015.
Blue Moon, Wikipedia.
Science Diction: The Origin Of The Word ‘Moon’, Science Friday, 20 January 2012.

Saturday, March 29, 2014

Earth's Satellite

Image by John Fowler

The Moon is Earth's only natural satellite.

The Moon is a prominent and receding presence in our lives. Silent and invariable, its waxing and waning phases, its visual presence and absence, imprints us with the cyclical patterns of nature.

The Moon's prominence in the evening sky, and its predictable phases, have influenced art and created mythologies since antiquity.

A full luminous Moon reveals the same face because, like the tuned gears of a watch, it is in synchronous rotation with Earth.

“Her antiquity in preceding and surviving succeeding tellurian generations: her nocturnal predominance: her satellitic dependence: her luminary reflection: her constancy under all her phases, rising and setting by her appointed times, waxing and waning: the forced invariability of her aspect: her indeterminate response to inaffirmative interrogation: her potency over effluent and refluent waters: her power to enamour, to mortify, to invest with beauty, to render insane, to incite to and aid delinquency: the tranquil inscrutability of her visage: the terribility of her isolated dominant resplendent propinquity: her omens of tempest and of calm: the stimulation of her light, her motion and her presence: the admonition of her craters, her arid seas, her silence: her splendour, when visible: her attraction, when invisible.”
― James Joyce, Ulysses

The Word

The word Moon is derived from the Old English mona, the Germanic mene, the Middle Dutch mane, the Old Saxon mano, as well as from Old Icelandic and Danish influence. Luna is the Latin word for Moon. The late Middle English word Lunar meaning ― of or related to the Moon ― is derived from the Latin luna.

Genesis

Depiction of Theia
crashing into Earth

The Moon wasn't always a satellite. The Giant Impact Hypothesis is the favored narrative for the genesis of the Moon.

Planetary scientists believe the Moon settled into its current configuration about 4,500,000,000 yeas ago. Anatomically modern humans appeared on Earth about 200,000 years ago which means the Moon is more than 20,000 times older than us.

The Giant Impact Hypothesis posits that the Moon was formed from debris caused by a glancing collision between the a protoplanet Earth and a planetoid about the size of Mars called Theia ― named after the mythical Greek Titan and mother of Selene, the goddess of the Moon.

Evidence supporting the Giant Impact Hypothesis is:

Earth's spin and the Moon's orbit having similar orientations, and
Stable isotope ratios of Earth and Moon rock are identical which infers a common origin.

The Moon has been Earth's tethered companion for billions of years. For thousands of years the Moon has awed and inspired artists, writers, philosophers, and natural scientists.