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Tellin' The Time

To measure lengths of time, people refer to regular, repetitive cycles, counting their iterations or fractions thereof.

ASTRONOMY

Days and nights, weeks and months, seasons and years are all defined based on constant and consistent rotations or revolutions (orbits) of the Earth, Moon, and Sun.

The omnipresent force of Gravity works to pull things in our Universe closer together, its apparent strength depending on relative masses and the distances between them. Our planet, its satellite, and its star are three roughly spherical balls of diverse matter, soaring and swirling through space for ages, settled into regular (almost) and repetitive cycles of motion with their neighbours.

A simple model of these three astronomical bodies balances them on one plane, with the Sun in the middle (the biggest and heaviest). The Earth (GAIA) travels in a circle (or ellipse) around the Sun (HELIOS), constantly re-tracing (relatively) the same path, completing sequential 'revolutions'. Meanwhile, Earth is spinning on its own axis (a diameter line through two fixed points on its surface known as the North pole and South pole), like a figure skater or ballerina, making 'rotations'. Revolutions happen slower than rotations: during each revolution, about 365(+0.25~) rotations occur. The Moon (SELENE) spins on her own axis too, and circles Earth like Earth circles the Sun — here, however, rotations and revolutions share the same speed, so that only one special half of the Moon's surface ever & always faces Earth. This effect is due to a phenomenon called tidal locking; there are similar cases elsewhere in our Solar System.

Humans witness rotations of Earth on its axis as oscillating periods of daylight and darkness. Observers almost everywhere on the planet experience the Sun repeatedly rising and falling through opposite horizons each morning and night: the physical direction toward which we look to see it climb above distant land or sea is named East, and the way it vanishes below is called West.

At mostly any place on Earth, since its rotational axis is tilted, the amount of daily sunlight exposure tends to shrink and swell over the course of a revolution, bouncing between minimal and maximal values at evenly spaced half-year intervals. More or less heat from the Sun contributes to temperature trends and ultimately the 'four seasons', whose schedules are inverted between the Northern and Southern hemispheres: people North of the Tropic of Cancer celebrate their annual 'Summer Solstice' in June and their 'Winter Solstice' in December, while others South of the Tropic of Capricorn begin Summer in December and Winter in June.

That portion of the Moon's surface which is simultaneously visible from Earth and illuminated by Sun-rays steadily waxes and wanes, with the visible portion of the Moon being totally dark when the Moon is between the Sun and the Earth, and fully lit when the Earth is between the Sun and the Moon. Dividing the cycle into four 'lunar phases', each lasts a little over 7 days.

MEASUREMENT

Naturally and unsurprisingly, our ancestors counted passing days and years. To allow precise discussion of fractional days, somewhere along the line, twenty-four equal 'hours' were invented which count from 0 to 23 once per day or, alternatively, from 1 to 12 twice per day. Moreover, each hour is divided into sixty equal 'minutes' and each minute split likewise into sixty 'seconds', both ranging from 00 to 59. Contemporary societies all over the globe employ this same system, although different locations use shifted labels relative to distant others such that the arrivals of sun-up and sun-down are comparable: when it's 7 AM in Toronto, it's 8 AM in Charlottetown and 7 PM (or 19:00) in Shanghai. Complexity arises as communities non-unanimously decide to adjust times further slightly forward & backward in Spring & Fall, attempting to maximize sunlight over typical waking hours or work-schedules.

A 'calendar' (lately the 'Gregorian') of 'weeks' and 'months' provides modern vocabulary for time intervals longer than a day but shorter than a year. A week is 7 days. A month, casually speaking, has around 30 days: more formally, calendar months are specifically prescribed partitions of each year's days into 12 parts, the first January and the last December. On the calendar, every past, present, and future date also belongs to one of seven 'week-day' varieties, with consecutive dates iterating predictably through the same names, first Sunday and last Saturday, in a loop.

Today (July 4th, 2020) is a Holiday for citizens of the United States of America (every year's Fourth of July has been enjoyed as an 'Independence Day' there since 1776). Today happens to be a Saturday, too.

Living today we are largely bound to follow conventions forged by centuries of incremental thought and standardization campaigns. Accepted numeric divisions and names, being somewhat inescapably arbitrary, are at least not without careful consideration or tested tradition.

MECHANICS

Shadows are cast by still objects at varying angles during daylight, as the Sun crosses the sky. Hence, fractional days are easily estimated outdoors in sunshine. Accurate times can be read from a 'sun-dial' device calibrated to its locale. Other ancient time-keeping devices also work in darkness (inside or at night), including sand-filled hour-glasses and water clocks.

These days, there are two ubiquitous formats communicating current times of day: 'digital' clocks appear on TV and computer screens, phones, and kitchen appliances, showing times as numeric codes of 1 or 2 figures for hours and 2 for minutes ([hh:mm]), or up to 6 digits with seconds ([hh:mm:ss]), possibly paired with an 8 digit date ([YYYY-MM-DD]). Large and powerful organizations (like the U.S. Government), having sophisticated staff and technology, maintain extremely precise 'atomic clocks' as reliable references for others. 'Analog' clocks are cleverly designed mechanical machines, geared to keep time rhythmically: one display style dominates across all house-hold fixtures, wrist-watches, and decorative rail-way station exteriors: arm-like 'hands' of distinct sizes are driven around the circumference of a circle, anchored to its center by their tail-ends. At noon & midnight, all heads should point straight up. The minute hand (usually longer & narrower) compasses the clock once per hour while the hour hand (shorter & wider) takes twelve hours. Synchronized & operational, the positions of the hour & minute hands continuously report hour & minute times of day & night.

Hands of analog clocks all tick or glide in the same direction — starting from the top, next to the right, then bottom, left, and back to top. This circular direction of motion is colloquially called 'clockwise', its opposite being 'counter-clockwise' (or 'anti-clockwise').

Viewed from high above the Earth's North pole, the Earth revolves counter-clockwise around the Sun. The Moon also revolves counter-clockwise around the Earth, and the Earth and Moon both rotate counter-clockwise about their axes.

ANALYSIS

Essential to any conception of Time is some intuitive unit pulse or duration — a Beat — which either may be subdivided into faster notes or collected to form larger measures.

Musicians create or control their tempo: they can stretch, squeeze, skip, skew, or switch their Beat through a performance, for effect, unlike the immutable Beat of a corporation's work-days, or a geologist's millennia (kiloannums), or an honest contractor's billable hours.

Beyond rhythm, in discussion of music, pitch too relates to Time and needs a Time-based unit to be fully understood: high C is twice as "fast" as middle C, imagining speeds of notes as the frequencies or wavelengths of idealized 'sound waves'.

Popular Western Music generally adheres to a 12 tone octave between every pair of 'C's, (or any other note, named using the first 7 letters of the alphabet, A to G, with another 5 notes transcribed using 'sharp' or 'flat' symbols, between pairs of consecutive letters and between G & A, but not between B & C, nor between E & F. Labelled and spaced in this way, the ascending sequence of degrees C--D--E-F--G--A--B-C is called a Major Scale (meanwhile the sequence A--B-C--D--E-F--G--A is a (Natural) Minor Scale).

Three pitches played simultaneously are a 'triad', a type of 'chord'. C----E---G is a Major Triad, and A---C----E is a Minor Triad.

A chord, like a note, has a sound wave profile, as a changing signal over a fixed period of time, and can be charted like a mathematical function. The Fourier Transform operator, a useful theory for engineers, can be described intriguingly (if not completely rigorously) as a machine capable of breaking input "chords" into those pure, isolated component "frequencies" defining them, so they can be more deeply understood or more easily replicated, communicated, and studied.

Different chords produced in different progressions evoke emotional reactions in listeners.

Sometimes, experimentation is healthy and fun — lose track of time exploring hidden harmonies.