- (Gyr)a unit of time equal to one billion years. The international symbol Ga is also used, the "a" being taken from the Latin word annus for a year.
Dictionary of units of measurement. 2015.
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gigayear — noun A billion (10) years These syntheses gave a fresh geological, as opposed to solely geophysical, view of the up to multi megayear and near gigayear mechanism responsble for the palimpsests of a general process of change in the upper crust: a… … Wiktionary
Giga- — For other meanings, see Giga (disambiguation) Giga (symbol: G) is a prefix in the SI system of units denoting 109, or 1,000,000,000. The Oxford English Dictionary reports the earliest written use of giga in this sense to be in the Reports of the… … Wikipedia
Brown dwarf — Brown dwarfs are sub stellar objects which are too low in mass to sustain hydrogen 1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no… … Wikipedia
List of unusual units of measurement — For units of measure primarily used in countries where English is not the main language, see the article specific to that country, a list of which can be found in the systems of measurement article. An unusual unit of measurement is a unit of… … Wikipedia
Himalia group — The Himalia group is a group of prograde irregular satellites of Jupiter that follow similar orbits to Himalia and are thought to have a common origin.The known members of the group are (in order of increasing distance from Jupiter): * Leda *… … Wikipedia
Byr — was formerly used in English language geology and astronomy as a unit of one billion years. The B is an abbreviation for billion (meaning thousand million), with yr simply an abbreviation for year . Today, the term gigaannum (Ga) is also used,… … Wikipedia
Gyr — or gyr can mean: *GYR is an abbreviation for Phoenix Goodyear Airport. *Gyr is an abbreviation for Gyrfalcon, a species of bird of prey *Gyr is an abbreviation for a gigayear, i.e. a billion (109) years. *Gyr is a Swiss German surname. *Gyr or… … Wikipedia
Early Earth — The early Earth is a term usually defined as Earth s first billion years, or gigayear. On the geologic time scale, the early Earth comprises all of the Hadean eon (itself unofficially defined), as well as the Eoarchean and part of the… … Wikipedia
GY — steht für: Guyana (nach ISO 3166), einen Staat in Südamerika die Abkürzung für Gymnasium eine gängige Abkürzung für Geophysik Gy hat folgende Bedeutungen: in der Physik die Kurzbezeichnung für die Maßeinheit der Energiedosis, siehe Gray die… … Deutsch Wikipedia
Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… … Universalium