The galactic year, also known as a cosmic year, is the duration of time required for the Sun to

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

once around the center of the Milky Way Galaxy.Cosmic Year
, Fact Guru,

University of Ottawa The University of Ottawa (), often referred to as uOttawa or U of O, is a Official bilingualism in Canada, bilingual public research university in Ottawa, Ontario, Canada. The main campus is located on directly to the northeast of Downtown Ot ...

One galactic year is approximately 225 million Earth years. The Solar System is traveling at an average speed of 230 km/s (828,000 km/h) or 143 mi/s (514,000 mph) within its trajectory around the Galactic Center,http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question18.html NASA – StarChild Question of the Month for February 2000 a speed at which an object could circumnavigate the Earth's equator in 2 minutes and 54 seconds; that speed corresponds to approximately 1/1300 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.Geologic Time Scale – as 18 galactic rotations
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Timeline of the universe and Earth's history in galactic years

The following list assumes that 1 galactic year is 225 million years.

References

{{DEFAULTSORT:Galactic Year Milky Way Types of year

Timeline of the universe and Earth's history in galactic years

See also

References