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Psychle: Planetary Day
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NIGHT PSYCHLE

What walks on four legs in the morning, two at noon and three in the evening? This is the riddle of the Sphinx from Oedipus Rex, the world’s most (in)famous play. If he fails to penetrate the mystery, his mortality will be proven.
Humans, he answers, who crawl on four legs as babies, who stand on two feet as adults, and who, with a cane, age. Aristotle articulates the same alignment of mortality with the solar cycle in Poetics, the first canonical text on storytelling. “Old age is to life as evening is to day; accordingly, the poet will speak of evening as ‘the old age of day’ and of old age as the ‘evening of life’ or (as Empedocles puts it) ‘the sunset of life” (Poetics, 25).
Before writing his treatise on storytelling, Aristotle would have seen Oedipus Rex, which transmutes the alignment of life and day into Oedipus’ story. As it goes, he is abandoned as an infant and grows into an adult, before, as prophesied by Tiresias, he “grop[es] the ground… with a stick” (Sophocles, 560).
The riddle—understood, at least, by such narrative greats as Sophocles and Aristotle—is quite astounding. Not only does it demonstrate an ancient religious alignment of life and day; but insofar as the riddle occurs within one of the greatest plays of all time, and insofar as the answer defines the structure of its protagonist’s arc, it also demonstrates the transmutation of solar-life cycles into character arcs and narrative structure. At the same time, its tripartite sequence can be seen as a forerunner to Aristotle’s emphasis on beginning, middle and end.
Earlier examples of this alignment can be found in the conflation of Osiris' life cycle with that of day and night. As the eye of Horus, his sun, is punctured at sunset, so, too, are the eyes of Orion, with whom Osiris shares a constellation. This is why the image of an aged Oedipus is incomplete before his eyeballs are popped. We age into blindness as sunset brings dark. But in the cases of Horus and Orion, who journey through night, their eyes come back with the sun.
To death or renewal, each example demonstrates how day and mortality can be fused into a dramatic arc and character journey.
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        What walks on four legs in the morning, two at noon and three in the evening?  This is the riddle of the Sphinx from Oedipus Rex, the world’s most (in)famous play. If he fails to penetrate the mystery, his mortality will be proven. 
	Humans, he answers, who crawl on four legs as babies, who stand on two feet as adults, and who, with a cane, age. Aristotle articulates the same alignment of mortality with the solar cycle in Poetics, the first canonical text on storytelling. “Old age is to life as evening is to day; accordingly, the poet will speak of evening as ‘the old age of day’ and of old age as the ‘evening of life’ or (as Empedocles puts it) ‘the sunset of life” (Poetics, 25).
     Before writing his treatise on storytelling, Aristotle would have seen Oedipus Rex, which transmutes the alignment of life and day into Oedipus’ story. As it goes, he is abandoned as an infant and grows into an adult, before, as prophesied by Tiresias, he “grop[es] the ground… with a stick” (Sophocles, 560).
     The riddle—understood, at least, by such narrative greats as Sophocles and Aristotle—is quite astounding. Not only does it demonstrate an ancient religious alignment of life and day; but insofar as the riddle occurs within one of the greatest plays of all time, and insofar as the answer defines the structure of its protagonist’s arc, it also demonstrates the transmutation of solar-life cycles into character arcs and narrative structure. At the same time, its tripartite sequence can be seen as a forerunner to Aristotle’s emphasis on beginning, middle and end.
	Earlier examples of this alignment can be found in the conflation of Osiris' life cycle with that of day and night. As the eye of Horus, his sun, is punctured at sunset, so, too, are the eyes of Orion, with whom Osiris shares a constellation. This is why the image of an aged Oedipus is incomplete before his eyeballs are popped. We age into blindness as sunset brings dark. But in the cases of Horus and Orion, who journey through night, their eyes come back with the sun. 
	To death or renewal, each example demonstrates how day and mortality can be fused into a dramatic arc and character journey.
For centuries, humans have attempted to explain the Sun in terms of their own worldviews. The Sun can be a god, a demon, a mischievous spirit, an omnipotent creator or a ruthless taker of life. Whatever role it plays, most cultures have recognized the significance of the Sun as prime controller of life on Earth. As far as we can surmise, all developing civilizations paid attention to the sky. The cyclic movement of the Sun, Moon, planets, and stars may have represented a kind of assurance and concept of order humans could strive after. What happens in the sky mirrors what happens in daily life. Did the regular occurrence of sunrise and moonset provide our ancestors with a concept of order, a stable pillar to which they could anchor their minds and souls?
Day, time required for a celestial body to turn once on its axis; especially the period of the Earth’s rotation. The sidereal day is the time required for the Earth to rotate once relative to the background of the stars—i.e., the time between two observed passages of a star over the same meridian of longitude. The apparent solar day is the time between two successive transits of the Sun over the same meridian. Because the orbital motion of the Earth makes the Sun seem to move slightly eastward each day relative to the stars, the solar day is about four minutes longer than the sidereal day; i.e., the mean solar day is 24 hours 3 minutes 56.555 seconds of mean sidereal time; more usually the sidereal day is expressed in terms of solar time, being 23 hours 56 minutes 4 seconds of mean solar time long. The mean solar day is the average value of the solar day, which changes slightly in length during the year as Earth’s speed in its orbit varies.
Circadian rhythms are 24-hour cycles that are part of the body’s internal clock, running in the background to carry out essential functions and processes. One of the most important and well-known circadian rhythms is the sleep-wake cycle.

Different systems of the body follow circadian rhythms that are synchronized with a master clock in the brain. This master clock is directly influenced by environmental cues, especially light, which is why circadian rhythms are tied to the cycle of day and night.
Diurnal cycles refer to processes or events that typically reoccur each day. Most daily cycles are caused by the rotation of Earth, which spins once around its axis about every 24 hours. The term diurnal comes from the Latin word diurnus, meaning daily. Diurnal temperature, diurnal cycles, diurnal tidal, and solar cycles affect global processes.

A diurnal temperature cycle consists of daily increases and decreases in temperature. The daily rotation of Earth causes the progression of daytime and nighttime, and the amount of sunlight falling on a given area (known as solar insolation). Insolation fluctuations give rise to both air and surface temperature changes. Except in unusual terrain, the daily maximum temperature generally occurs between the hours of 2 PM and 5 PM, and then decreases until sunrise the next day. The angle of the sun to the surface of Earth increases until around noon when the angle is the largest (i.e., the sunlight most direct).
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