银河年
The galactic year, also known as a cosmic year, is the duration of time required for theSun to orbit once around the center of theMilky Way Galaxy.[1] Estimates of the length of one orbit range from 225 to 250 million terrestrial years.[2] The Solar System is traveling at an average speed of 828,000 km/h (230 km/s) or 514,000 mph (143 mi/s) within its trajectory around the galactic center,[3] a speed at which an object could circumnavigate the Earth's equator in 2 minutes and 54 seconds; that speed corresponds to approximately one 1300th of the speed of light.
source: 维基百科
