Wiktionary
n. 1 (context astronomy English) the time it takes for the Solar System to orbit around the center of the Milky Way Galaxy, estimated to be from 225 to 250 million years. 2 (context astronomy English) by extension, the time it takes a celestial body to complete a quasi-orbit in a galaxy
Wikipedia
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. Estimates of the length of one orbit range from 225 to 250 million terrestrial years. 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, 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.
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.
Usage examples of "galactic year".
At the least, I would recommend that the Human Polity be put on probationary status in the Concilium for one Galactic year—.
If Gaia is really Earth, despite the difference in names, then Gala, by your previous argument, ought to have a period of rotation of just one Galactic Day, a period of revolution of just one Galactic Year, and a giant satellite that revolves about it in just one month.
If Gaia is really Earth, despite the difference in names, then Gaia, by your previous argument, ought to have a period of rotation of just one Galactic Day, a period of revolution of just one Galactic Year, and a giant satellite that revolves about it in just one month.
One persistent heritage of pre-antiquity was the standard Galactic Year, used by all worlds of the Imperium in official business.