Time

As of the Exodus, time is measured using the Universal Standard Calendar.

Periods
As of the Exodus, human history is divided into four distinct eras, each with their own individual sub-eras, called ages. Combined, these four eras cover all of human history from the arisal of anatomically modern humans to the present day.

Prehistoric Era
This era lasted almost 200,000 years, making it by far the longest era currently in existence. The Prehistoric Era lasted from the arisal of anatomically modern humans to the founding of Ancient Mesopotamia, roughly three thousand years before the beginning of the Common Era.

Ancient Era
The Ancient Era comprised roughly three thousand years, from Ancient Mesopotmia to the alleged birth of the religious figure of Jesus Christ in some mythologies. The Ancient Era is commonly considered to be when true human civilisation first arose, giving birth to societies such as ancient Egypt, the Greek city-states, and the Roman Empire, which continue to exert their influence on modern humanity even now, long after they're gone.

Common Era
Though lasting only two thousand years, give or take, Common Era is widely considered to be the most transformational era in human history thus far. Lasting from the alleged birth of Jesus Christ to the time of the Exodus, when humanity departed Old Earth for the stars, the Common Era is oft acknowledged to be when humanity truly began to flourish. In this era, powerful kingdoms and rulers arose, expanding their influence across the world with economic and military might. Over time, these kingdoms settled, crystallizing into the nation-states of the late-20th and early-21st centuries. Many modern nations and corporations in the Known Human Territories are direct successors or continuations of these governments.

Exodus Era
The Exodus Era is the shortest of the four eras so far, but it has not yet ended. Lasting from the eponymous Exodus event to the present day, the Exodus Era currently comprises roughly 1100 years, a time period during which humanity has reached its true potential, expanding the Known Human Territories across the Achelois Galaxy.

Universal Standard Calendar
Upon establishing interstellar communications with the remaining Saviour Ships, one of the first proposals brought before the newly-reformed International Forum for Cooperation was for a standardised timekeeping system. With human civilisation spread across a number of different planets, each with their own orbital period (though, oddly enough, similar rotational speeds), it was argued that the measuring time by Old Earth's standards was illogical and outdated. With a nearly unanimous vote, the General Assembly of the International Forum for Cooperation authorised the creation of the Universal Standard Calendar, administered by the TimeKeeper Virtual Intelligence system and overseen by the International System of Units Commission.

Galactic Mean Time is used as the base comparison, and is maintained as the official time when not on a planet, similar to the function of Greenwich Mean Time pre-Exodus. All voidcraft and space stations use Galactic Mean Time, and synchronise according to the International Forum for Cooperation's TimeKeeper Virtual Intelligence system, which collates data from over a hundred thousand atomic clocks spread out across the Known Human Territories.

Units
The standard unit of time under the Universal Standard Calculator is the second. A comparison of time values according to the Universal Standard Calendar is displayed below. As shown, one standard year is divided into 365 days, or 13 months of 28 days each plus one unattached day.