# Time delation or clock malfunction

1. Feb 9, 2012

### R Power

Time delation or clock malfunction!!

Using an example of light clock, it shows light takes more time now to reflect between reflectors due to elongated path as to moving observer, so 1 sec gets elongated. But this could also mean that the clock malfunctions as compared to observer. I mean one second is one second, how it can change???? light now takes more time to complete its one cycle doesn't mean 1 sec gets elongated. It's just the clock which now takes more than one second to show one second increment to the observer. That means clock malfunctions for the moving observer but it can't elongate 1 sec. Why will biological processes get slower? So why will aging occur?

2. Feb 9, 2012

### HallsofIvy

Re: Time delation or clock malfunction!!

No, there doesn't have to be any clock involved. If A is moving at a high speed relativer to B, then B will observe everything about A is slower. It is NOT the case that the clock has "malfunctioned".

3. Feb 9, 2012

### harrylin

Re: Time delation or clock malfunction!!

We call the count of progress of physical processes "time". According to SR, what is true for a light clock must be true for all physical processes, thus also for age. While one may philosophize about the existence of some kind of universal or "absolute" time, the only time that we can measure is that of physical processes. If according to our measurements all of them slow down, it is common to call this common slowdown "time dilation". A more conservative phrasing of the same is "clock retardation".
Perhaps you would still call that "clock malfunction", but as it is in the nature of the best clocks that we can make, few people would agree with calling it such.

4. Feb 9, 2012

### ghwellsjr

Re: Time delation or clock malfunction!!

R Power, if you have two clocks in relative motion, they each will observe the other one to be running slow, so how do you decide which one is malfunctioning?

5. Feb 9, 2012

### R Power

Re: Time delation or clock malfunction!!

Obviously for each them the other one will malfunction.

6. Feb 9, 2012

### ghwellsjr

You said one second is one second. Which one is correctly measuring that one second?

7. Feb 9, 2012

### R Power

Re: Time delation or clock malfunction!!

hmmm...... so you want to say that time is not some universal duration its just the duration between two successive events. For each of the moving observers the successive events occur slowly at the other one.
But for your question each clock measures one second correctly for its own observer but wrong for the other observer.

8. Feb 9, 2012

### ghwellsjr

Re: Time delation or clock malfunction!!

Well, that's not my idea, it's Einstein's. Before he came up with this idea, people thought that there was a universal time based on an absolute rest state and since the surface of the earth is constantly changing its motion through space, all our clocks must be suffering a slow-down. But Einstein said, "Time is what a clock measures", so if two identical clocks run at different rates only because they are moving with respect to each other, that must mean that time is relative and that makes it right for each clock. Neither clock is wrong, they just have a different definition of what a second is. This might seem to make no sense at all, in fact, Einstein pointed this out in his 1905 paper introducing Special Relativity, but he went on to show how you could create a concept of a Frame of Reference involving both space and time in such a way that it makes perfect sense.

9. Feb 9, 2012

### R Power

Re: Time delation or clock malfunction!!

So, now for both the clocks the other one is slow. What will happen in case these both clocks meet each other. Imagine the clocks reverse their path to meet each other.

10. Feb 9, 2012

### ghwellsjr

Re: Time delation or clock malfunction!!

It depends on exactly what you have in mind. For example, if to begin with, both clocks passed each other so that they could set their clocks to the same time, and then some time later according to each clock, they both turned around in the same way and eventually met up again, then their clocks will display the same time when they pass each other the second time.

However, if only one of them turned around and headed back to the other one, then that clock will display an earlier time when they pass.

11. Feb 9, 2012

### Staff: Mentor

Re: Time delation or clock malfunction!!

Here is an answer that I gave previously to a similar question: