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Einstein's Relativity -> Paradoxes
#77801
06/15/06 02:51
06/15/06 02:51
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Joined: Jul 2002
Posts: 2,813 U.S.
Nadester
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I was reading up the other day on Einstein's theory of relativity (which, as you know, has been tested) - particularly time travel paradoxes. A little background on the original experiment: Quote:
In 1975, Professor Carrol Alley tested Einstein's theory using two synchronised atomic clocks. Carol loaded one clock onto a plane, which was flown for several hours, while the other clock remained on the ground. At the end of its flight, the clock on the plane was slightly behind the one on the ground. Time had actually slowed down for the clock on the plane. It had travelled forward in time.
Picture this: A person is in a train without any walls. Another person is standing outside the train. There is a flashlight on the floor of the train facing the ceiling. The train drives by the person standing outside the train. Hypothetically speaking, the person not on the train sees the light move dialognally (assuming the train was going VERY fast), while the person inside the train, relative to the motion of the train, ONLY sees the light move straight up. Thus, the person on the ouside, sees the light moving a further distance in the same amount of time as the person on the inside of the train (picture a right triangle). Now, keep in mind, light CANNOT be accelerated, the speed of light is a constant. So, how is it possible that the light moves a greater velocity in the same amount of time? This is because time slows down for the person inside the train. Freaky concept?
From the Pythagorean Theorem, the equation can be derived:
T = t1 / sqrt( 1 - ( ( x * c^2) / c^2 ) )
Where T = time of the object at rest, t1 = time of the moving object, c = the speed of light, and x = a variable to gauge how close the velocity is to the speed of light. (Note that the c^2's cancel out).
Now, say the train is going 99% the speed of light, thus x is .99. Time for the person on the train, t1, is 1 year. Plug it in. You'll find that time itself on Earth has passed by 7 years. Weird, eh? Now, try .999 - 20 years. .9999 - 70 years.
Now, even creepier - say you are going the speed of light. Plug it into the equation: sqrt(1-1) = 0. 1 / 0 = undefined. Undefined = infinity. The universe has literally ended, an infinite amout of time has past - time becomes irrelevent to you.
Continuing, what would happen if you go beyond the speed of light? While this appears to a barrier in our universe, if you CAN go beyond it, the opposite would happen - time would slow down to a reverse.
Lastly: The paradox. Imagine I discover a way to go beyond the speed of light, and I travel back in time. The year is 1970. My father in a senior in high school. I walk up to him, pull out a shotgun, and shoot him dead. Poof - I disappear, as my father was never allive to meet my mother, and thus I cease to ever have existed. But wait: If I havn't existed - then who could have shot my dad? Which means he'd still be allive, which means I'd be born, which means I'd go back in time and shoot him, which means I'd never have existed! Freaky? I think so.
That's all I have. Correct me if I'm made any mistakes, and please share any other paradoxes
--Eric
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Re: Einstein's Relativity -> Paradoxes
[Re: jcl]
#77803
06/15/06 12:27
06/15/06 12:27
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Joined: Oct 2004
Posts: 4,134 Netherlands
Joozey
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Quote:
Still, there is no paradoxon. You can not go back and kill your father. The reason is that when you go back with the above method, you also need to move in space - so you end up at a position so far from you father's location that you'd need a gun with a bullet faster than light to kill him. And this, according to relativity theory, is impossible.
Never thought about that, it makes sense . Thanx for this explanation! Lol
Click and join the 3dgs irc community! Room: #3dgs
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Re: Einstein's Relativity -> Paradoxes
[Re: Joozey]
#77804
06/15/06 12:47
06/15/06 12:47
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Joined: Sep 2003
Posts: 2,174 Israel, Haifa
ROMAC
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Quote:
Still, there is no paradoxon. You can not go back and kill your father. The reason is that when you go back with the above method, you also need to move in space - so you end up at a position so far from you father's location that you'd need a gun with a bullet faster than light to kill him. And this, according to relativity theory, is impossible.
What if it was a circular motion, wouldn't you then be closer to your father?
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Re: Einstein's Relativity -> Paradoxes
[Re: PHeMoX]
#77806
06/15/06 16:31
06/15/06 16:31
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Did I understood that right? By moving the time changes? I mean the clock on the airplane could be slower because its pretty cold up there, and the colder it is the slower things go. But that is no change of time(?)
In anyway, what I am realy woundering about. Planets are moving realy fast and realy slow. And (their) movement depends from the view of other objects, what means there is no real speed. From point of view of itself itīs not moving. But time is going on. All planets time is going the same (or am I wrong). Doesnīt matter if you are on the moon or earth. But moon and earth move with different speed. And what about the sun. Itīs not moving(?) but it is reacting real fast with all itīs burnings and explosions. So why isnīt the suns time = 0?yeah, yeah, I know. The sun is moving for sure. But still itīs time is going same as on earth I guess when I watch these explosions there. In these movies they look slow because are so big and far away. Like watching the horizon when driving.
:L
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Re: Einstein's Relativity -> Paradoxes
[Re: EX Citer]
#77807
06/15/06 17:28
06/15/06 17:28
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Joined: Nov 2004
Posts: 1,011 South Africa
capanno
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Quote:
In 1975, Professor Carrol Alley tested Einstein's theory using two synchronised atomic clocks. Carol loaded one clock onto a plane, which was flown for several hours, while the other clock remained on the ground. At the end of its flight, the clock on the plane was slightly behind the one on the ground. Time had actually slowed down for the clock on the plane. It had travelled forward in time.
Couldnt it be that the one clock had a little malfunction? Maybe because of the flight and g-forces?
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Re: Einstein's Relativity -> Paradoxes
[Re: capanno]
#77808
06/15/06 17:52
06/15/06 17:52
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Joined: Jul 2000
Posts: 11,321 Virginia, USA
Dan Silverman
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Quote:
I mean the clock on the airplane could be slower because its pretty cold up there, and the colder it is the slower things go.
Quote:
Couldnt it be that the one clock had a little malfunction? Maybe because of the flight and g-forces?
No (on both accounts). The clock used was an atomic clock. Here is some information on atomic clocks:
http://science.howstuffworks.com/atomic-clock1.htm
http://en.wikipedia.org/wiki/Atomic_clock
The nature of an atomic clock is what would have caused Professor Alley to choose them for his experiment.
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Re: Einstein's Relativity -> Paradoxes
[Re: PHeMoX]
#77810
06/16/06 00:25
06/16/06 00:25
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@Phemox, you can only feel a change in velocity, and thus the accleration would be the only problem. But whose to say you have to accelerate to the speed of light so fast that it is harmful to you? It doesn't matter as long as you get there.
@Capanno, pretty much what Dan said, but also the fact that this is supported mathematically, so it's no real surprise that the clocks were different.
@EX Citer, the speed that the planets move is nearly irrelevent compared to the speed of light. Similiarly, the difference in the speed of the sun and the speed of the planets is also quite irrelevent in comparison to the speed of light. (299,792,458 meters/sec) Still, time does move slower for us than for the sun, but the difference is so small that it's pretty much unnoticable.
Also, I forgot to mention, the process of time travel I stated above is known as time dialation, for anyone interested in further reading.
--Eric
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