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Faster than light
PurpleYouko:
--- Quote ---Makes perfect sense to me. I guess the question I have here is how these two guys know which one is moving and which one is sitting still? It might as well be that the ship is stationary and the asteroid is passing by :)
Also, on the practical side of things: these two dudes seem to observe and measure the speed of light without any special equipment. In real life they'd be somewhat distanced from the beam of light in question and will use some physical phenomena to a) measure the distance the light travels and B) measure the time. These measurements would introduce another level of calculations and make the problem really complicated! I'm glad I'm not a physicist to figure all this stuff out :)
--- End quote ---
Exactly right.
It all makes perfect sense within th eprecepts of relativity.
And there is no known way that these observers could actually measure the stuff in this way. You have to assume a few things here but they shouldn't change the fundamentals of the equations.
Your point about the relative speed of the spaceship and the asteroid actually lead on to my next point which is where a lot of this logic falls apart for me.
Let's imagine that the asteroid is actually a second spaceship going the other way. It too has a little guy doing a light beam experiment as well as watching the other guy's light experiment through some kind of subspace observation module or something.
In this scenario both observers will see time slowing down for the other observer while their own stays the same.
If both ships travel in a wide circular path and eventually meet again while constantly observing each other (again with the imaginary subspace instant communications module), each one should see the other as being much younger than he is himself. Eventually, each observer will see the other one remain young while he himself dies of old age.
This is somewhat of a paradox that I just can't get my head around.
I realize that a wide circular path means an acceleration is applied which could change things according to special relativity so let's assume that this path is an orbit of a large black hole or something so that the gravity will exactly cancel the acceleration of travelling in a circle.
How do you square these observations with each other?
:blink: PY :blink:
Zelos:
talking about relativity? sweet I love how this evolve. well when it comes to the timedilation that happen when you begin to reach speed close to light can easly be calcylated whit this formula:
T2=T1/root(1-(V/C)²)
where T2=the time for us
T1= the time on the ship
V=velocity of the ship
C=speed of light
so lets say they are moving at 99% of the light, their time will then be slowed down so that 1 second for them is 7 for us. but both is still moving whit the same speed relative to the blackhole on question they are orbeting. but to reach this speeds they need to be very close to the blackhole. So now of a suddenly the timedilation from gravity become important, the formula for that is:
T2=T1/root(1-(R1/R2))
where T1/T2 is the same as whit speed
and R1=Schwarzschild radius (the place where the escape velocity is C, nothing can from here return)
and R2 is the distance from the center of the blackhole.
but both cant be older for each other and still be young to it self. where have you heard that? I would like to read it, but I dont think that is possible, coz what happen then when both stop moving? they are younger compared to each other, and still older compared to each toher, its not possible to be older/younger compared to both. but if you can show me where you read it I´ll gladly read it
:lecture: zelos :lecture:
PurpleYouko:
--- Quote ---its not possible to be older/younger compared to both. but if you can show me where you read it I´ll gladly read it
--- End quote ---
I didn't read it. it is an exercise in logic. just think it through.
Also these observers don't need to be anywhere close to the speed of light and they could be orbiting the entire universe rather than a black hole. It doesn't matter.
Each observer sees his own time as normal and measures light speed at C.
Each observer also sees light moving further on the other spaceship than the observer on that spaceship does.
Therefore each observer sees time moving more slowly on the opposite ship than it does on his own.
Inference: The observer will grow old and die while the other won't.
This clearly can't be correct.
I can't see anything wrong with the logic so what is the deal here?
:wacko: PY :wacko:
Zelos:
well, if they have the same speed compared to the same thing they will never become older compared to each other. they have the same flow of time. if they dont have the same speed or are compared to different thing one will have a slower flow of time and will be younger when they reach the same speed to compared to the same thing
:lecture: zelos :lecture:
shvarz:
PY, I found a web-site that explains special thoery of relativity in very simple terms: http://www.phys.vt.edu/~takeuchi/relativity/notes/
You should check it out. The question that you posed is a variant of the old "twin paradox" and it is explained right here: http://www.phys.vt.edu/~takeuchi/relativit.../section15.html
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