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On July 22 2011 06:06 Nawyria wrote:Show nested quote +On July 22 2011 05:53 ]343[ wrote:On July 22 2011 05:18 Nawyria wrote:On July 22 2011 05:06 Sabin010 wrote:
The real question is what if the twins kept in contact via morse code through entagled particles? If twin A measures his entangled particle on one end, he knows the wavefunction of twin B's particle on the other hand. However, when twin B measured the particle on his end, he has no way of knowing whether the result he gets came from a wavefunction that collapsed because twin A measured the other particle. Entangled particles cannot actually transmit information. WHOA thanks I was wondering about this! But enough pairs of entangled particles could transmit information with high probability, no? The "information" transmitted is the wavefunction of the particles, which determines the probability with which a particular result will be found when measured. So in this way measuring the particle on one side impacts the measurement on the other side. However, there is no way of telling whether a measurement was conducted on one side, so you can never tell if the outcome of a particular measurement was due to random chance, or due to the collapse of a wavefunction.
Can't you thermally isolate one entangled partner such that it doesn't decohere, then cause a reduction of this wavefunction by "measuring" its coupled partner, which would not have otherwise otherwise occured due to near abs zero temperatures. The probability distribution of this waveicle after it has "spread out" again will then be altered from what you originally had? You sure you can't transmit information FAPP ftl using this?
Noob question ty. Obv answer is no given the consensus of physicists on this question... but I'd like to know why
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Blazinghand
United States25555 Posts
On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty
Doesn't work. The system you describe initially can maintain orbit. The system you describe in the last paragraph is not the same system, since it has a generator turbine in it, and one of the bodies has water, as well. I see no reason why every quality of the first system should be necessarily present in the second, or why the absence of any quality of the first system on the second system is meaningful to the first system.
For example: A bicycle, unattended, falls over. But a bicycle with a kickstand does not fall over. Sounds like a paradox! How could this be a bicycle and ALSO NOT FALL OVER? The answer is, of course, something was added to the system.
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On July 22 2011 01:07 skunk_works wrote:
how does traveling at the speed of light keep you from getting old?
It doesn't. It just makes your frame of reference for time slower and therefore to someone with a faster frame of reference (i.e. not moving), it looks like you're moving and aging more slowly.
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On July 23 2011 01:55 Blazinghand wrote:Show nested quote +On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty Doesn't work. The system you describe initially can maintain orbit. The system you describe in the last paragraph is not the same system, since it has a generator turbine in it, and one of the bodies has water, as well. I see no reason why every quality of the first system should be necessarily present in the second, or why the absence of any quality of the first system on the second system is meaningful to the first system. For example: A bicycle, unattended, falls over. But a bicycle with a kickstand does not fall over. Sounds like a paradox! How could this be a bicycle and ALSO NOT FALL OVER? The answer is, of course, something was added to the system.
It's meant to convey a point. The keyword I'm trying to use is real, meaning uneven with dirt and crap and crusts on it. If we take away the turbine & water, then wouldn't whatever causes THAT n-body system to decay (the system with water/turbine) ALSO cause the n-body system of dirt rocks to decay, hence meaning that no real n-body system can maintain orbit for t->infinite?
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I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ?
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No. The point is that with your turbine, you take energy from the system. With friction and all that stuff, you don't. But you might transform rotational energy into heat, which would have the same effect.
You always simplify. In the first system, you simplify that there is no energy lost to anything, which in a real system obviously is not the case. (The energy is not literally "lost", it just gets transfered to something else that does not effect the rotation) Thus, as a result, if you have any those effects, you obviously can not retain the same motion for infinity.
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On July 23 2011 02:29 Diks wrote:
I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ?
No, the clock won't "feel like turning slower". The clock is turning slower because time in its frame of reference passes slower. The clock thinks it turns as fast as always. But it thinks that any clock in a different frame of reference is turning at a different speed than it should be. But all clocks by themselves turn at the exact speed they are supposed to.
Thus, as you said, in your supposed case of instanteneous communication, the earthward twin would experience the Spacetwin to talk slower, and the spacetwin would experience the earthtwin to talk faster than he is supposed to. But both feel like they are talking at the usual speed.
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On July 23 2011 02:29 Diks wrote:
I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ?
The perception of time will be exactly the same for both people. Your premise is flawed.
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Blazinghand
United States25555 Posts
On July 23 2011 01:57 arbitrageur wrote:Show nested quote +On July 23 2011 01:55 Blazinghand wrote:On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty Doesn't work. The system you describe initially can maintain orbit. The system you describe in the last paragraph is not the same system, since it has a generator turbine in it, and one of the bodies has water, as well. I see no reason why every quality of the first system should be necessarily present in the second, or why the absence of any quality of the first system on the second system is meaningful to the first system. For example: A bicycle, unattended, falls over. But a bicycle with a kickstand does not fall over. Sounds like a paradox! How could this be a bicycle and ALSO NOT FALL OVER? The answer is, of course, something was added to the system. It's meant to convey a point. The keyword I'm trying to use is real, meaning uneven with dirt and crap and crusts on it. If we take away the turbine & water, then wouldn't whatever causes THAT n-body system to decay (the system with water/turbine) ALSO cause the n-body system of dirt rocks to decay, hence meaning that no real n-body system can maintain orbit for t->infinite?
If you define "real" as "sufficiently uneven that it can't maintain orbit", then yes, obviously.
I'm not really sure what you're trying to get at, here. Are you noting that physical models hold certain variables constant and ignore others to make their calculations? This is correct. For example, non-universal projectile motion models use equations that work best when you're standing at about sea level. As you climb in elevation, gravity is ever-so-slightly weaker, meaning that the equations are ever-so-slightly less accurate. Also, since these equations don't account for wind or air resistance, despite being accurate most of the time, for projectiles shaped like feathers or parachutes, you'll lose some accuracy.
On July 23 2011 02:41 MangoTango wrote:Show nested quote +On July 23 2011 02:29 Diks wrote:
I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ? The perception of time will be exactly the same for both people. Your premise is flawed.
If instantaneous communication was possible, special relativity and physics as we know it would have to be rewritten. The "Paradox of the Twins" wouldn't exist because time dilation wouldn't exist because time would no longer be relative. The fundamental laws of nature would have to be rewritten for instantaneous communication to be possible. At the very least, we'd find our understanding of the universe to be enormously flawed until we created a new physics.
Asking about the Paradox in that situation, where the physics are fundamentally different, is about as relevant as asking how to cast Expelliarmus in our physics situation.
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On July 23 2011 02:53 Blazinghand wrote:Show nested quote +On July 23 2011 01:57 arbitrageur wrote:On July 23 2011 01:55 Blazinghand wrote:On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty Doesn't work. The system you describe initially can maintain orbit. The system you describe in the last paragraph is not the same system, since it has a generator turbine in it, and one of the bodies has water, as well. I see no reason why every quality of the first system should be necessarily present in the second, or why the absence of any quality of the first system on the second system is meaningful to the first system. For example: A bicycle, unattended, falls over. But a bicycle with a kickstand does not fall over. Sounds like a paradox! How could this be a bicycle and ALSO NOT FALL OVER? The answer is, of course, something was added to the system. It's meant to convey a point. The keyword I'm trying to use is real, meaning uneven with dirt and crap and crusts on it. If we take away the turbine & water, then wouldn't whatever causes THAT n-body system to decay (the system with water/turbine) ALSO cause the n-body system of dirt rocks to decay, hence meaning that no real n-body system can maintain orbit for t->infinite? If you define "real" as "sufficiently uneven that it can't maintain orbit", then yes, obviously. I'm not really sure what you're trying to get at, here. Are you noting that physical models hold certain variables constant and ignore others to make their calculations? This is correct. For example, non-universal projectile motion models use equations that work best when you're standing at about sea level. As you climb in elevation, gravity is ever-so-slightly weaker, meaning that the equations are ever-so-slightly less accurate. Also, since these equations don't account for wind or air resistance, despite being accurate most of the time, for projectiles shaped like feathers or parachutes, you'll lose some accuracy.
What I'm saying is that, possibly, this thought experiment means that you can't have a real n-body planetary system that maintains orbit no matter the configuration of said bodies.. even in principle. Am I being confusing?
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Blazinghand
United States25555 Posts
On July 23 2011 02:55 arbitrageur wrote:Show nested quote +On July 23 2011 02:53 Blazinghand wrote:On July 23 2011 01:57 arbitrageur wrote:On July 23 2011 01:55 Blazinghand wrote:On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty Doesn't work. The system you describe initially can maintain orbit. The system you describe in the last paragraph is not the same system, since it has a generator turbine in it, and one of the bodies has water, as well. I see no reason why every quality of the first system should be necessarily present in the second, or why the absence of any quality of the first system on the second system is meaningful to the first system. For example: A bicycle, unattended, falls over. But a bicycle with a kickstand does not fall over. Sounds like a paradox! How could this be a bicycle and ALSO NOT FALL OVER? The answer is, of course, something was added to the system. It's meant to convey a point. The keyword I'm trying to use is real, meaning uneven with dirt and crap and crusts on it. If we take away the turbine & water, then wouldn't whatever causes THAT n-body system to decay (the system with water/turbine) ALSO cause the n-body system of dirt rocks to decay, hence meaning that no real n-body system can maintain orbit for t->infinite? If you define "real" as "sufficiently uneven that it can't maintain orbit", then yes, obviously. I'm not really sure what you're trying to get at, here. Are you noting that physical models hold certain variables constant and ignore others to make their calculations? This is correct. For example, non-universal projectile motion models use equations that work best when you're standing at about sea level. As you climb in elevation, gravity is ever-so-slightly weaker, meaning that the equations are ever-so-slightly less accurate. Also, since these equations don't account for wind or air resistance, despite being accurate most of the time, for projectiles shaped like feathers or parachutes, you'll lose some accuracy. What I'm saying is that, possibly, this thought experiment means that you can't have a real n-body planetary system that maintains orbit no matter the configuration of said bodies.. even in principle. Am I being confusing?
Yeah I'm confused about the part where you have a "real n-body planetary system... in principle" (emphasis mine). Does the system exist in reality, or in principle? If It's in principle, then the math functions, and if it's an "in reality" one, as you have described, then it is A) not in principle and B) not the same system that's being described anyways since it's made out of crappy crusty watery rocks rather than spherical rocks.
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Ok, I'm going to answer these one-by one to the best of my ability. I'm still an undergraduate, so there might be some flaws in my explanations.
On July 23 2011 01:33 arbitrageur wrote:
Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
In general, an ideal n-body system of point masses is not solvable analytically for N>2. As far as I know, these systems are in general not stable for infinite time. Making the masses realistic only complicates this problem. Regardless, going on to the second point:
Assuming the water on your planet is subject to friction, heat will be generated out of the gravitational push and pull of other planets. As the thermal energy increases, the kinetic energy of the system decreases and therefore the total mechanical (kinetic + gravitational) energy decreases. In the case of a two-body system, this means that the planets will creep closer together. For t large enough, eventually enough of the mechanical energy of the system will be transformed into thermal energy that the orbits of one or more planets intersect and collapse.
Even if the water was frictionless and you somehow managed to build a turbine that generated electricity, the same process would occur. In this sense, Tidal power isn't quite a sustainable energy source, as we're basically tapping into the mechanical energy of the earth-moon system.
An interesting point you've brought up.
EDIT: As the matter of fact, a difference in gravitational pull on one side of the planet's centre of mass and the other side of the planet's centre of mass stretches and compresses the material the planet is made of, which causes heat generation. Therefore, in general, no 'real' n-body system will be stable as mechanical energy is dissipated through the motion of the planets.
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On July 23 2011 01:48 yoshi_yoshi wrote:Show nested quote +On July 22 2011 06:06 Nawyria wrote:On July 22 2011 05:53 ]343[ wrote:On July 22 2011 05:18 Nawyria wrote:On July 22 2011 05:06 Sabin010 wrote:
The real question is what if the twins kept in contact via morse code through entagled particles? If twin A measures his entangled particle on one end, he knows the wavefunction of twin B's particle on the other hand. However, when twin B measured the particle on his end, he has no way of knowing whether the result he gets came from a wavefunction that collapsed because twin A measured the other particle. Entangled particles cannot actually transmit information. WHOA thanks I was wondering about this! But enough pairs of entangled particles could transmit information with high probability, no? The "information" transmitted is the wavefunction of the particles, which determines the probability with which a particular result will be found when measured. So in this way measuring the particle on one side impacts the measurement on the other side. However, there is no way of telling whether a measurement was conducted on one side, so you can never tell if the outcome of a particular measurement was due to random chance, or due to the collapse of a wavefunction. Dumb question: How are entangled particles going to be more useful than just giving two people pieces of paper saying "YES" and "NO". Then when each of them look at their paper they know what the other one got.
A completely valid question, and you are right. This is exactly what a system of entangled particles does, with a minor difference. If I look now and see I have "NO", I could look again in a second or two and see that I have "YES".
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Blazinghand
United States25555 Posts
On July 23 2011 03:37 Nawyria wrote:Show nested quote +On July 23 2011 01:48 yoshi_yoshi wrote:On July 22 2011 06:06 Nawyria wrote:On July 22 2011 05:53 ]343[ wrote:On July 22 2011 05:18 Nawyria wrote:On July 22 2011 05:06 Sabin010 wrote:
The real question is what if the twins kept in contact via morse code through entagled particles? If twin A measures his entangled particle on one end, he knows the wavefunction of twin B's particle on the other hand. However, when twin B measured the particle on his end, he has no way of knowing whether the result he gets came from a wavefunction that collapsed because twin A measured the other particle. Entangled particles cannot actually transmit information. WHOA thanks I was wondering about this! But enough pairs of entangled particles could transmit information with high probability, no? The "information" transmitted is the wavefunction of the particles, which determines the probability with which a particular result will be found when measured. So in this way measuring the particle on one side impacts the measurement on the other side. However, there is no way of telling whether a measurement was conducted on one side, so you can never tell if the outcome of a particular measurement was due to random chance, or due to the collapse of a wavefunction. Dumb question: How are entangled particles going to be more useful than just giving two people pieces of paper saying "YES" and "NO". Then when each of them look at their paper they know what the other one got. A completely valid question, and you are right. This is exactly what a system of entangled particles does, with a minor difference. If I look now and see I have "NO", I could look again in a second or two and see that I have "YES".
The reason that this is possible is that the data transmitted, instead of being a bit (1 or 0) is a qubit (a probability waveform made out of both |1> and |0>). This means that instead of being in a binary state, it's in a superposition of two binary states, with both |1> and |0> totally going on.
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On July 23 2011 02:29 Diks wrote:
I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ?
The question I ask you then, is instantaneous to whose eyes? A big part of the Theory of Special Relativity is that simultaneity is in the eye of the beholder. Two events that occur simultaneous to you, may not occur simultaneous to me.
Since all inertial systems are equal (this a fundamental postulate), there is no system we can point to and say "This observer has the correct notion of simultaneous". The only way we can work our way around this is to say "The signal travels instantaneously according to my perception of time". However, this generates an unresolvable paradox as below:
Paradox
+ Show Spoiler [picture] +
1) Twin A sends Twin B an instantaneous question according to his perception of simultaneous.
2) Twin B sends Twin A an instantaneous answer according to his perception of simultaneous.
3) Twin A receives Twin B's answer before he ever asked the question.
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Question...
Why would one twin hear the communication of the other as slowed. Wouldn't there just be a delay in the communication due to the time it took for the light to reach twin a/b.
IIRC the speed of light is constant, and redshift/blueshift is due to an accelleration either towards or away from the reciever of the signal.
So with this in mind the communications would be heard by both twins with a normal speech pattern just a long pause.
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+ Show Spoiler +On July 23 2011 03:51 Nawyria wrote:Show nested quote +On July 23 2011 02:29 Diks wrote:
I want to complicate the OP a bit and let's imagine we have a theorical instantaneous conversation with the twins (This is not physically possible, this is just a brain fuck scenario).
They will talk like instant telepathy during the travel time.
The perception of time for the traveling twin will be different on the way back to earth. Time will feel like it goes slower for him, he'll feel like an hour last a bit longer and when his twin on earth will instantaneously talk to him, he'll feel like his twin is talking slower than usual. When he'll land to earth, there won't be any weird moment of "how can you be there ? You told me 1 minute ago that you were coming back in 2 years"
The key is not the mesure of time, but the perception. I bet clock will feel like turning slower in a fast space travel.
I'm curious but seriously lack of physical education on the subject, can anyone help clarify this ? The question I ask you then, is instantaneous to whose eyes? A big part of the Theory of Special Relativity is that simultaneity is in the eye of the beholder. Two events that occur simultaneous to you, may not occur simultaneous to me. Since all inertial systems are equal (this a fundamental postulate), there is no system we can point to and say "This observer has the correct notion of simultaneous". The only way we can work our way around this is to say "The signal travels instantaneously according to my perception of time". However, this generates an unresolvable paradox as below: Paradox+ Show Spoiler [picture] +1) Twin A sends Twin B an instantaneous question according to his perception of simultaneous. 2) Twin B sends Twin A an instantaneous answer according to his perception of simultaneous. 3) Twin A receives Twin B's answer before he ever asked the question.
Thank you for your enlightment, I know realise my question didn't really make sens.
I have something that still tickle me about "two events that occur simultaneous to you, may not occur simultaneous to me."
So if I get this right; time and space are undissociable.
When I see the mathematics model, the time/location is always refered as a dot, but we, human have a body that covers an area. Can I legitimately say that my right leg lives in the past and my left leg in the future ? (even by fractions of ns)
Do we have some sort of "referencial center of the time/space perception" inside our brain ?
I'm sorry for my questions that may have no sense one again :/
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Wow, this is probably the most intellectual and educated thread in TL.
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On July 23 2011 04:23 Trainrunnef wrote:
Question...
Why would one twin hear the communication of the other as slowed. Wouldn't there just be a delay in the communication due to the time it took for the light to reach twin a/b.
IIRC the speed of light is constant, and redshift/blueshift is due to an accelleration either towards or away from the reciever of the signal.
So with this in mind the communications would be heard by both twins with a normal speech pattern just a long pause.
This is partly because of time dilatation. That is to say, two observers with a relative speed between observe each other's clocks as running slower. This is because our notion of what space and time shifts as the speed between two inertial frames becomes of order c.
Another way to think about it is this: If I'm travelling at some reasonable fraction of the speed of light away from you (say, 50%) and I say a sentence to you that takes me 10 seconds to say, then by the time I've finished speaking I'll be 5 lightseconds further away from you relative to where I was when I started speaking and the end of the message will take 5 seconds longer to reach you than the start of the message. This means that you'll receive my original 10-second message smeared out over 15 seconds and thus I'll appear to be talking in slow-motion.
Edited for mistakes
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On July 23 2011 04:55 Nawyria wrote:Show nested quote +On July 23 2011 04:23 Trainrunnef wrote:
Question...
Why would one twin hear the communication of the other as slowed. Wouldn't there just be a delay in the communication due to the time it took for the light to reach twin a/b.
IIRC the speed of light is constant, and redshift/blueshift is due to an accelleration either towards or away from the reciever of the signal.
So with this in mind the communications would be heard by both twins with a normal speech pattern just a long pause. This is partly because of time dilatation. That is to say, when the two twins travel away from each other they observe each other's clocks as running slower; when the two twins travel towards each other, they observe each other's clocks as running faster. This is because our notion of what space and time shifts as the speed between two inertial frames becomes of order c. Another way to think about it is this: If I'm travelling at some reasonable fraction of the speed of light away from you (say, 50%) and I say a sentence to you that takes me 10 seconds to say, then by the time I've finished speaking I'll be 5 lightseconds further away from you relative to where I was when I started speaking and the end of the message will take 5 seconds longer to reach you than the start of the message. This means that you'll receive my original 10-second message smeared out over 15 seconds and thus I'll appear to be talking in slow-motion.
Thanks.... i always forget to carry the time dilation
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EPT![[image loading]](http://i.imgur.com/zjysk.jpg)
