Time

Temporal measurement is a primordial and essential matter for sentient living beings, as it marks an anchorage among the infinity of a continued and unreachable progress of events - and thus existence - and, following, the inclusion of the proper beings among this impregnable stream. Time and civilizations always dwell together as societies only rise when proper methods of temporal measurements are put in place ; cyclic events (celebrations, religious days...) are the fundations required to erect a community of people while the awareness of a limited time in each day and in life span forces people to overcome their basic instincts and accept to live together...

Generaly speaking, temporal mesurement appears in 2 distinct but linked forms :
 * Universal form : Here, the course of time is based on a fixed point, independant from someone interaction, and used to locate the position in the global time scale ; calendars are typically this kind of tool.
 * Contigent form : This form is used when it is required to count the passage of a certain amount of time with a starting point chosen by the individual ; hourglass or time candle enters in this category.

PARAGRAPH I : DEFINITIONS
The Day is the most basic unit of time of any temporal measurement tool and is about approximately the period of time durng which Terra completes one full rotation around its star Sol. While the duration of a day varies according the stellar position of the planet, it is set out of reach of sentient beings and thus the duration is the same for everyone ; where nations and civlizations differs lays in the subdivision of this basic unit and its employement along their calendar. Days are divided in unequal periods of light and night, save for the 2 days of the year when day and night have the same lenght (equinoxes), and this variation is often used to put in place the calendar ; many nations chose the shortest day or the shortest night as starting point of the year, religious celebration days, etc...

A Year is a period representing the whole course of Terra around Sol ; b Seasons are specific division of a solar year, marked by distinct changes in weather, ecology, biology and duration of daylight/nyghttime cycle ; nature and duration of seaons changes according the position on the planet, as polars regions have 2 main seasons when temperate ones can meet up to 4 of them. Many animal and vegetal species regulate their live and behaviour according the course of seasons ; they reach the most intensity when days are longers while remains quiet and often hibernate when days are shorter.