Galactic year

The galactic year, also known as a cosmic year, is the length of time needed for the Sun to orbit once around the center of the Milky Way Galaxy.Cosmic Year , Fact Guru, University of Ottawa One galactic year is 230 million Earth years.  The Solar System is traveling at an average speed of 230 km/s (828,000 km/h) within its arc-like path 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 travel around the Earth's equator in 2 minutes and 54 seconds; that speed goes along with about 1/1300 of the speed of light.
The galactic year provides a conveniently usable unit for showing cosmic and geological time periods together. Very differently, a "billion-year" scale does not allow for useful difference between geologic events, and a "million-year" scale needs some rather large numbers.Geologic Time Scale – as 18 galactic rotations

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Category:Milky Way
Category:Units of time