Peacekeepers of the Vast/Time in the Galaxy

"...time is a valuable thing, watch it fly by as the pendulum swings, watch it count down to the end of the day, the clock ticks life away..." -Old Earth Proverb

Tracking the passage of Time in a vast galaxy is a difficult concept. Across hundreds of worlds, orbits are different, cultures vary, and classical measurement of time begins to become meaningless.

ISL Time

Among ships doing business across space registered with the Interstellar League, time is typically measured using standards related to the rotation and revolution of the planet Trazinus, the ISL capitol world. This provides a useful baseline for anyone who lives somewhere without the traditional temporal delineations normally granted to those who live on a planet - itinerant ship crews, asteroid colonists, etc. The ISL standard is similar enough to Earth that the distinction is mostly immaterial.

Solaran Union

In the Solaran Union most humans still track the passage of time via the Old Earth measurement and a 24-hour clock. Even on worlds where a day cycle is shorter or longer, it is merely expressed in a shorter number of hours than 24 during a day, but it is viewed as being "shorter" than a "real" Earth day; age is measured against a 365-day/8760-hour year, just like Earth's.