Gya 1947920 222134231 2008-06-27T18:46:40Z Lightbot 7178666 Units/dates/other {{otheruses}} In [[astronomy]], [[geology]], and [[paleontology]], '''Gya''' (for [[giga]] years ago) is often used as an [[Units of measurement|unit]] of [[time]] to denote length of time before the present. Specifically, one Gya is equal to 10<SUP>9</SUP> [[year]]s ago. A unit identical to Gya is [[bya]] (for "[[1000000000 (number)|billion]] years ago"), which may be in more widespread use. However, some scientists prefer Gya because it uses the [[SI]] prefix [[giga-]] and thus avoids confusion over whether the short-scale ([[American English|American]]) billion (10<SUP>9</SUP>) or long-scale ([[British English|British]]) billion (10<SUP>12</SUP>) is meant, as well as avoiding preference for one of the two definitions of billion over the other. In some scientific literature, the term Gya has been replaced by '''[[Gigaannum|Ga]]''' ([[Giga-annum]]). == See also == * [[annum]] * [[Before Present]] * [[bya]] * [[mya (unit)]] [[Category:Units of time]] [[hu:Gya]]