Cosmic year

The Cosmic year also known as a Galactic year, is the duration of time required for Pluribus Unum to orbit once around the center of the Milky Way Galaxy . Estimates of the length of one orbit range from 225 to 250 million terrestrial years. The Union Core system (Pluribus IUnum) is traveling at an average speed of 828,000 km/h (230 km/s) or 514,000 mph (143 mi/s) within its trajectory around the galactic center, a speed at which an object could circumnavigate the Earth's equator in 2 minutes and 54 seconds; that speed corresponds to approximately one 1300th of the speed of light.

The galactic year provides a conveniently usable unit for depicting cosmic and geological time periods together. By contrast, a "billion-year" scale does not allow for useful discrimination between geologic events, and a "million-year" scale requires some rather large numbers

The Galactic year was proposed as a base for Union time keeping but it was rejected as it was M-0 Centric and did not reflect all Union members that are not in  the M-0 galaxy. See Time Keeping reforms .

Howeverthe Eduk , the Narth and the Coven use versions of the Galactic Year to express the passage of time.

The Exalted  the World of Old was expressing the time in Cosmic Years