Ok, let's ignore the current StarTrek dating system for a second. I'm curious as to what people would consider a good way to measure the passage of time that would be acceptable to any race, and what portions it would be measured in. ie. fractions of galaxy rotation, or the vibration of a particle.
im curious, since a day on earth is obviously not a day on vulcan or romulus. different races have tolerences for different day lengths etc. and going from one day on a planet from one day on ship, space station, or other planet would likely cause jet lag.
even something as simple as measuring someones age becomes a problem.
I guess it could be some fraction of the galactic year. That's what every species within this galaxy can agree on.
The interstellar time unit (the "space second") would be defined by a pulsar that everyone can see.
And measuring age... well, you get your own age based on your solar system, and your "galactic age". And you can convert that to every other age just as easy as you can convert currencies.