Galactic year
Approximate orbit of the Sun (yellow circle) around the Galactic Centre.
The galactic year, also known as a cosmic year, is the duration of time required for the Solar System to orbit once around the center of the Milky Way Galaxy.[1] Estimates of the length of one orbit range from 225 to 250 million "terrestrial" years.[2]
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.[3]
Timeline of universe's and earth's history in galactic years
The following list assumes that 1 galactic year is approximately 225 million years.
Visualisation of the orbit of the Sun (yellow dot and white curve) around the Galactic Centre (GC) in the last galactic year. The red dots correspond to the positions of the stars studied by the
European Southern Observatory in a monitoring programme.
[4]
See also
References