# Relative time notation

1. Mar 21, 2004

### psiclone

Is time believed to be a constant or is it merely a function of the perception of the observer? My understanding is that if Astronaut Poole was just outside of an event horizon and Astonaut Bowman was just inside the event horizon, their repsective perceptions of time would be drastically different.

As such, is there any sort of objective measurement of time?

Further, is there some sort of scientific notation for time that indicates an oberver's viewpoint or some sort of notation for a theoretical "objective" time like a superscipt or subsciprt?

2. Mar 21, 2004

### psiclone

C'mon guys, help me out here. Is the speed of light a constant that could be used to derive an "absolute second in time" or something? I don't know how to properly describe what it is I want say in a fomulaic manner.

3. Mar 22, 2004

### Staff: Mentor

Yes, the rate of the passage of time depends on the frame of reference (speed and gravity) of the observer. That's a major component of Einstien's Relativity. You can synchronize clocks in different frames via Einstein's theory.

4. Mar 22, 2004

### jcsd

The answer is 'no', the laws of nature prefer no refernce frame; notions of absolute time go out the window and simlairly out go notions of absolute space. However spacetime (in it's own way) is absolute, that is to say that the spacetime interval between two events remains the same for all observers whatever their relative velocities.

5. Mar 22, 2004

### Severian596

From my experience, you develop "frames of reference" like frames S and S', then refer to what each of them sees with phrases like, "Relative to frame S, S' moves in the +x direction with a velocity of 3/4c."

6. Mar 25, 2004

### turin

Look up "proper time" (&tau;).

Within the event horizon (in the Schwarzschild metric), the radius becomes temporal (the radius inevitably changes in a consistent sense, just like time), so, your intuition served you well.

7. Mar 26, 2004

### ranyart

One has to be certain that a question is fully explored in order to answer?

So your statement:As such, is there any sort of objective measurement of time?
.

This is my take on your far reaching question of course!

Last edited: May 2, 2004