A yahren is a Colonial measurement of time, analogous to an Earth year. The plural form is usually the same as the singular, "yahren", although "yahrens" is also used for the Colonial equivalent of "years" in some episodes.
- Within some fan circles, a yahren is considered to be around two-thirds (2/3) the length of an Earth year, thus helping to explain the relative longevity of Colonial people compared to Terran humans; in "War of the Gods, Part II", Adama claims that the average human lifespan, "Cylons permitting," is about 200 yahren. This reasoning is picked up in Richard Hatch's sequel novels. The glossary of terms in the first novel, Armaggedon, reads "yahren--equivalent to a year; two hundred fifty days."
- Yahren might be based on the German word Jahren, which is pronounced the same, though it means "Years." Jahr would be the singular form.
- The original script for Greetings From Earth has a key that says a centon is a minute, a centar is an hour, a secton is a week, and a yahren is a year.
Usage in the Re-imagined Series
- In the Re-imagined Series, time appears to be measured by the Colonials as is done on Earth with the term year. Since a year is considered the time it takes for the real-world Earth to revolve once around the sun, the use of "year" is confusing, given that the Twelve Colonies consist of several Earth-type worlds that may orbit a sun or series of suns, or even exist in adjacent solar systems and so have revolution times that may differ dramatically. The Fleet stays on New Caprica for 380 "days" before the Cylon fleet arrives, and this is deemed to be approximately a year.
- Curiously, a brief mention of "yahren" appears in the documents visible at Armistice Station in the Miniseries. This should be treated as an homage to the Original Series, and not be taken too seriously, as the prop department has produced errors in some other documents shown on screen.