why dark o'clock of course!

Depends on what time zone you're over.

Time on Earth is measured in refference to the position of the Earth and the Sun. This refference doesn't apply in space (What if you were in the center of the Earth? What Year would it be if you were in the Center of the Sun?). You would need a new method. The one that comes to mind would be the rate of expansion of the universe. We can estimate when the Big Bang was, and therefore, through the rate of espansion, set a time frame in space. And you can use the time light takes to travel a standard distance in space to be the increment. (i.e. the equivalent of seconds, on Earth.)

What if I'm in orbit around Mars? I think Americans would use Eastern Time as the standard and each nation otherwise such as Russia would use Moscow time, etc since that is where their central commands are located.

Stardate 1432.2 (as of July 20, 2007, 1900 hours UT Earth)

Time is a human invention, unnecessary in space

Gosplegirl: I was just wondering...'why'... you asked this multi-variable complex question? Im serious! A simple, yet 'deep' question, on your part! Multi, because of the variables you did not include...such as 'speed'..and its [time] reference frame. 'Time', Gosplegirl...is regulated by "speed". Incredibly, the faster something travels...the 'slower' it moves in time. This same phenomena is why one cannot 'catch' the end of a beam of light...the faster you travel to reach the end of the beam, the slower the time curve becomes. The faster the speed of persuit, the slower 'time' becomes. In the world of physics, it is called 'time dilation'! In other words...in a space ship, you leave Earth traveling at 'only' 1 percent of the speed of light...or 671,000,000 mph. After checking your watch you observe 'one' hour of time has elapsed...you then turn around and head home. You land and according to 'your' watch...'only' two hours of time has elapsed...however, back on Earth, your husband is upset because in 'his time' you have been absent for 223.36 hours, or 18.61 days!! Einstein rocked the science world with this mathematical bombshell, when he was in his early twenties. So...what 'time' is it in space?Again...time is related to speed! So...give us the variables, sweety!

It makes sense to me that in space people would use GMT as a reference, where I believe it's going on 7:30 AM right now.

I'm pretty sure space time is permanently set on 4:20