Dating Systems and Distance Measurements

Dating Systems

  In the articles and timelines gathered here, I have used the Earth based dating system BCE (before the common era) and CE (common era) for the convenience of the reader who is most likely to be familiar with this standard. This should in no way be understood to suggest that it was in widespread use in the far places and futures where I have deployed it. Within specific stories, time keeping schemes more appropriate to the period will be found. From the start of the 4th dynasty of the Resource Management World Government, for example, it became commonplace to use the Islamic calendar on Earth which employs the suffix AH (After Hijri). Given that the Islamic New Year does not begin January 1 (since it is lunar based) and that a Hijri year is 11 days shorter than a Common Era year, there is no direct correspondence between years of the two eras. A given Hijri year will usually fall in two successive Western years. A Western year will always fall in two or occasionally three successive Hijri years. As a rough approximation:-   AH = (CE − 622) × 33 ÷ 32
  CE = AH + 622 − (AH ÷ 32)   After the foundation of the Republic in 2540 CE they established their own dating system, FR (from the Foundation of the Republic) with a year zero starting then and a count determined by the length of the year on Gall V, which is somewhat shorter than an Earthly year. Republican dates can be calculated from common era dates using the formula:-   FR = (CE - 2540) ÷ 0.65133   The Society Of Contemporary Races has a formal dating system based on the angular position within their galactic orbits and the current periodicity of five specific reference pulsars. This complex but precise astronomical calendar is used for the marking of great historical events, such as species emergence and extinctions but is almost never employed for everyday use. Instead, as you might expect, each species has at least one calendar based on events and timings derived from its home world, whilst colonies will very often use a more local scheme suited to their astronomical circumstances since some kind of alignment with day and night cycles and planetary seasons is a highly desirable feature for any timekeeping method.   In dealings between one another, the various races and planets have simply come to terms with the necessity for frequent date and time conversions and on common projects will agree to adopt the most convenient calendar on an ad hoc basis.  

Distance Measurements

  I have adoped the Earth based standard of the light year in places where interstellar distance measurements are quoted as this is likely to be more familar to the reader. A light year is the distance light travels in a year and is 9.46 trillion kilometres (9.46×10^12 km). Naturally, a light year only makes sense in the context of an Earthly year so it is a parochial unit. Within the Society Of Contemporary Races a number of alternative systems were in use, but the most widely used standard was the IRD, or interstellar reference distance. One IRD is 7.21 light years. A description of the origins and derivation of this unit is found in the article on Reference Point   The Earth based system of the AU is used to refer to intra-system distances.