No real purpose in space-time?

[mixinman7]

...if the observers time is passing faster than any other reference, that observer will see its time passing slower than the other reference sees, and the other reference will see the observer's time passing faster. If you ignore the role of the observer, time will go faster for anything that travels faster.

Three people in a row missed this word (than)?

No, this is not correct. Any observer will always see its own time passing normally and anybody else's time passing slower. (As WannabeNewton said)

That's what I meant, thanks. Except that the observer will see its clock traveling faster than anyone else's time if that anyone is traveling slower.

 

[mixinman7]

...while in the Lorentz transform t'=γ(t-xv)...

For one because the units don't work out right. The ratio of energy to mass would have units of speed squared, not time.

I might be wrong, but I'm thinking this ties back to what you said earlier DaleSpam. "Lorentz transform t'=γ(t-xv)." The x means distance, v means velocity, t means time, and y means 1/sqrt(1-v2/c2) right? Also, what is the ' mark next to t? Last, why isn't mass in this equation?

Thanks

 

[mixinman7]

There is no 'faster'. That implies absolute velocity, which is flouting a basic tenet of relativity - i.e. that only relative velocity is meaningful.

If you by 'faster', you mean something that accelerates, you are wrong to say time goes faster, because elapsed times on kinked or curved worldlines are shorter than on straighter ones...

I think I might be misunderstanding this comment. The way I think of it, if the role of the observer is ignored, the statement "time will go faster for anything that travels faster" is true because the sequence of events measured from a given perspective of anything traveling faster will elapse faster. If I look at the clock an a spaceship traveling near the speed of light, I will see its clock moving faster than mine. Am I wrong?

 

[PAllen]

Except that the observer will see its clock traveling faster than anyone else's time if that anyone is traveling slower.

This statement is complete nonsense. A given observer sees themselves as stationary. All other clocks are traveling faster and going slower for any observer (or stationary and the same). There is no meaning, for a given observer, for other clocks to traveling slower - slower than stationary ??!

 

[PAllen]

I think I might be misunderstanding this comment. The way I think of it, if the role of the observer is ignored, the statement "time will go faster for anything that travels faster" is true because the sequence of events measured from a given perspective of anything traveling faster will elapse faster. If I look at the clock an a spaceship traveling near the speed of light, I will see its clock moving faster than mine. Am I wrong?

Yes, you are wrong. If you look at the clock on a spaceship moving near the speed of light relative to you, you will see the clock moving much slower. People on the rocket will see your clocks moving much slower. That is the essence of relativity.

 

[mixinman7]

Yes, you are wrong. If you look at the clock on a spaceship moving near the speed of light relative to you, you will see the clock moving much slower. People on the rocket will see your clocks moving much slower. That is the essence of relativity.

This concept seems to contradict the twin paradox. If a twin leaves on a rocket and travels near the speed of light, he can come back and be much younger than his twin. So during that trip, the man in the rocket should be able to look at the twin's clock and see that the twin on Earth's clock is moving slower. The twin on Earth should be able to see the twin on the rocket's clock going faster. For this to be wrong I think you'd have to ignore the idea of seeing each other's clock simultaneously. That would be true while considering the time it takes for light to travel. But I am not referring to seeing clocks from telescopes. I mean if the two clocks are measured simultaneously, I'd think the difference should be as I described. Is there an element of backwards time-travel that I'm not getting?

 

[PAllen]

This concept seems to contradict the twin paradox. If a twin leaves on a rocket and travels near the speed of light, he can come back and be much younger than his twin. So during that trip, the man in the rocket should be able to look at the twin's clock and see that the twin on Earth's clock is moving slower. The twin on Earth should be able to see the twin on the rocket's clock going faster. For this to be wrong I think you'd have to ignore the idea of seeing each other's clock simultaneously. That would be true while considering the time it takes for light to travel. But I am not revering to seeing clocks from telescopes. I mean if the two clocks are measured simultaneously, I'd think the difference should be as I described. Is there an element of backwards time-travel that I'm not getting?

No, it does not contradict twin differential aging. As long as the rocket is moving inertially, Earth sees rocket clocks slower and vice versa. Fundamentally, the rocket comes back younger because it has not followed an inertial path between start and stop, while the Earth observer has traveled a (near) inertial path. Inertial paths between spacetime points are paths of maximum proper time (in SR; GR is more complex).

During the rocket's outbound inertial flight, it is as I said - by any point of view, each considers the others clocks slower (direct observation; compensating for doppler and light delays; whatever). Once the rocket turns, things are more complex. You can talk about visual appearance, and you can talk about several schemes for matching up simultaneity between rocket and earth. However, it is invariant that the rocket will have aged less by the time it returns.

 

[Daverz]

This concept seems to contradict the twin paradox.

At this point you are really just wasting people's time. Why not read up a bit first on special relativity? I recommend https://www.amazon.com/dp/0691141274/?tag=pfamazon01-20