If you had a spacefaring civilization and they routinely travelled beyond the speed of light, what kind of time keeping and calender would they use? I imagine that the old calenders wouldn’t make much sense anymore, and how would you be able to keep track of time if you’re going FTL? Wouldn’t everybody’s clocks get all messed up and stuff?
Stardates. 
Actually, the time of day shouldn’t be a problem on the ship. Once you landed on the planet, you’d try to adjust things for the planetary day.
If you traveled faster than light speed, you’d be traveling backwards in time. One of the many reasons you can’t travel faster than light speed.
So you’ll have to postulate the specifics of these fantasy warp drive in order for us to formulate our opinions. Otherwise the answer is: You cannot travel faster than light speed, hence time keeping in those situations is not a consideration.
I thought it just slowed time down? So, what if it just slowed time down? And since you mention it what if it did cause you to go back in time? What would you do to figure out time would every planet have their own seperate calendar?
Speeds approaching the speed of light result in time slowing down relative to the rest of the Universe; speeds greater than the speed of light lead to time travel (or at least, can). For the ship itself, clocks on board the ship will work just fine: They won’t be messed up at all relative to the folks on the ship. For the planets you visit, you could use whatever system you wanted.
If you had actual Faster than light travel it would be outside the bounds of relativity, so I doubt the time contraction would be related to that of relativistic speeds. As for how you keep time, Relativity has an effect on the time differential between any two given planets based on their speed, in the same galaxy this difference is likely to be low as even the difference in speed between stars close to the center of the galaxy and those farther out is not high, however, this does mean that time passes at a tiny but measurably different rate on those different planets. You would have a ‘time’ for each planetary system, and a seperate ‘time’ aboard your ship depending on how FTL travel works (which being fictional is usually defined by the author). The situation would in some ways be similar to timekeeping in different time zones, except that the time zones are not a matter of linear order, but of local relativistic speed and the consequential effect on the passage of time. If you wanted to know what time it was on Altair VI so you know if Robby the Robot will have dinner ready when you get there, you would consult a computerized chart that tells you what ‘time’ it is there by performing the necessary calculations and assumes that nothing has changed the variables in a major way (after all, if you are postulating FTL travel, why not accelerate and decelerate entire solar systems?) Then when you get there you check the local time to see if you are right just in case.
My two cents,
AllFree
I sort of get this. Let’s say there’s an eclipse that covers your planet, you watch it while on the planet, then get into a space ship, travel at 110% of the speed of light away, and a bit later slow down and look back with a telescope. You outran the light moving away from the planet, so now that you’ve slowed down that light that left the planet during the eclipse passes you by again and you get to see the eclipse (which occured before you left) all over again. I get that. Edit: The eclipse is just an example in this case since you can view it from far away, substitute it for a baseball game and a super powered telescope if you’d like. Didn’t want to add any confusion.
But what happens if instead you head off faster than the speed of light, and then turn right around and come back to the planet? You outrun the light one way, but then you’re going across the grain of light, so to speak, the other way. Presumably, on the trip back, the light would travel by you faster on this trip, and so it would appear to you that the time on that planet is sped up. Would the effects of the apparent time reversing (when you’re travelling away) be counteracted of the speeding up on the return trip so that when you got back time had actually advanced? Or is this just the totally wrong way of thinking about it? I know physics at the extremes can be very counterintuitive.
No, that is not why faster-than-light travel is impossible. If you couched the same argument in terms of, say, the speed of sound, you would arrive at the incorrect conclusion that faster-than-sound travel is impossible. But there is nothing inherently paradoxical about receiving a signal and then travelling ahead of it and receiving it again.
Instead, it is more accurate to think of there being a universal maximum speed, and light happens to be one thing that can travel at that speed. Another way of looking at it is that c represents infinite speed, and that is why you can’t go any faster. For if you are travelling at c, in your frame of reference it takes no time at all to travel anywhere.
Imho, it would be like the clocks now that use radio signals to always have the correct time. When you stopped, you would get a signal from your home planet or nearest base or whatever telling you the correct time.
My original statement was a bit misleading. We cannot travel FTL because, well we can’t. It’s a governing law of the universe that we would need an infinite amount of energy to reach LS.
Rather the time travel involved in FTL is a paradox that would arise if we could somehow travel faster than light. The concept of universal simultaneity does not exist. Therefore it could be possible for a ship traveling at FTL to leave here, reach Proxima Century and arrive back on earth BEFORE it left.
Besides messing with some possible grandfather paradoxes, this would vex starfleet’s Temporal Prime Directive police to no end. And who wants that?
Can someone remind me what “light” we are referring to when we mention c? Is it the light from a candle, a very bright torch, or your “average” star?
c = 186,000 miles per second sounds very specific for such a vague term as “light”.
ps. And is it perchance, the only sum that makes the “expert’s” calculations make sense?
It’s the speed that photons move at. I don’t think they care what generated them.
Assuming it’s somehow possible to have FTL travel and NOT have time paradoxes, then you could possibly refer to some quasi-universal time based on the time elapsed since the Big Bang. Or does Relativity make even that variable?
Think of it this way: c is the constant we use to represent the fastest speed that something can travel at (~300,000 km/s or ~186,000 MPH). One of the consequences of getting close to that speed is that relativistic mass of the object increases. So, the only thing that can actually reach that speed is something that has no mass to begin with. It so happens that photons, of which light is composed, have no [effective] mass, and so can reach that speed. Therefore, we can say that the speed of light is the theoretical maximum speed. Of course, we’re really talking about the speed of light in a vaccuum, since light traveling in other media goes slower.
ETA: The “light” we are referring to can be generated by any source. The light from a candle, torch or a star differs only in wavelength, and the medium through which they travel. Light from any source passing into a perfect vaccuum will always travel at c.
You could do that, but there’s no single reference frame for which that’s the time coordinate. It wouldn’t be a significant problem unless you’re travelling over cosmological distances, though (i.e., much greater than within our Galaxy, or even cluster of galaxies).
I think that’s why Star Trek invented “stardate.” Either that, or it sounded good. 
The amount of time dilation that occurs at any given speed is constant isn’t it? If so then we should be able to program the ships clock/computers/chronologicalmultigoobas to compensate automatically.
I seem to recall reading that something like this is already in place for GPS satellites. Because of the greater speed they are travelling while in orbit a compensation had to be incorporated into their software to compensate for the (very very minor) dilation that occurs.
Just to complicate things I believe, after going a few rounds with Chronos, that anything you do to arrive at a point in space faster than a photon would going the “long” way around constitutes FTL travel.
So, while we may not be able to push a spaceship faster than light we might conjecture that we could pass through a wormhole (a short cut if you will) between two points. Star Trek warp travel is similar in that it essentially shortens your trip while you personally never exceed light speed.
Despite never exceeding light speed it still gets us into time travel problems.
Never got a good grasp of why that is so though.
A I understand it (as much as one can understand something not permitted by our current understanding of the laws of physics), once you’re going faster than light, there’s nothing stopping you from returning to your starting point at a time before you left. Star Trek conceives of its FTL somewhat arbitrarily to eliminate that possibility.
Some of the error is introduced by frame dragging, which is not due to traveling at a significant fraction of c, but rather due to the mass of Earth and it’s gravitational effect on space-time.