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Makep
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Are there speeds greater than the speed of light? If so, then can we discard c to embrace the new faster speed as the universal constant to explain relativity?
Sure, I can easily calculate speeds greater than the speed of light. None of them achievable by an object with mass, in reality, though...Makep said:Are there speeds greater than the speed of light?
You can't just discard a universal constant because you feel like it. It isn't an arbitrary thing.If so, then can we discard c to embrace the new faster speed as the universal constant to explain relativity?
Nonsense, superluminal communications implies no such conversation.kev said:Log of superluminal radio conversation. ...
I don’t think Maxwell or Einstein would consider that a coincidence. Neither should we.mgb_phys said:A better explantion might be that relativity says there is a maximum speed of information and Maxwell's equation coincidentally say that the speed is 'c'.
mgb_phys said:>Log of superluminal radio conversation.
Isn't really a satisfactory explanation. Imagine a species that was blind, it could develop a similair theory based on sound, you obviously can't have any speed faster than sound because then you would be able to get the answer before the question had reached you.
kev said:Log of superluminal radio conversation.
RandallB said:Nonsense, superluminal communications implies no such conversation.
RandallB said:They should also be able to figure out if they are on a preferred ref frame by simply checking over the superluminal communications channel to see if their local clocks are actually synchronized as the luminal communications channel implies.
:rofl:kev said:Log of superluminal radio conversation.
Makep said:Are there speeds greater than the speed of light? If so, then can we discard c to embrace the new faster speed as the universal constant to explain relativity?
kev said:P.S. As I hinted at before, if we accept the notion that superluminal communication is possible, we probably have to reject the notion of free will and accept that the future is predetermined.
First I don’t accept superluminal communications as possible at all – you’re the one making unfounded conclusions about reality based on assumptions on what would happen if you built such a system, like the idea we have no free will.kev said:To accept superluminal communications requires that at least one of the following is rejected:
1) Cause precedes effect in any reference frame.
2) The laws of physics are the same in any inertial reference frame.
3) There is no absolute reference frame.
Which of these principles do you propose to reject?
Nonsense, it has everything to do with clock synchronizationIt has nothing to do with clock synchronization. Bob does not even have to have a clock. The sequence of events can be entirely determined by Alice's single clock.
Only if we accept your notion that you can definitely establish that some future reading on Bob’s clock is absolutely simultaneous with the current time on Alice’s clock.… if we accept the notion that superluminal communication is possible, we probably have to reject the notion of free will and accept that the future is predetermined.
kev said:To accept superluminal communications requires that at least one of the following is rejected:
1) Cause precedes effect in any reference frame.
2) The laws of physics are the same in any inertial reference frame.
3) There is no absolute reference frame.
Which of these principles do you propose to reject?
RandallB said:What you are doing here is accepting an unfounded assumption to support what amounts to a Science Fiction story line.
First I don’t accept superluminal communications as possible at all – you’re the one making unfounded conclusions about reality based on assumptions on what would happen if you built such a system, like the idea we have no free will.
I do not need to reject a principle;
I reject the notion that “3) There is no absolute reference frame.” is a principle.
kev said:Log of superluminal radio conversation.
RandallB said:Nonsense, superluminal communications implies no such conversation.
If the parties both rebroadcast the conversation over a luminal transmission both could pick up a echo (time delayed) of both sides of the same casually ordered conversation from the other at a later time on the luminal communications channel.
They should also be able to figure out if they are on a preferred ref frame by simply checking over the superluminal communications channel to see if their local clocks are actually synchronized as the luminal communications channel implies
RandallB said:It does not say you can arbitrarily pick any frame as the absolute reference frame. (and here you even graph and use two different frames and selectivly use both as absolute)
RandallB said:Simultaneity says the only time you can know two events are actually simultaneous is when they happen physically spatially next to each other.
JakeStan said:...
That is you are using our intuition to disregard a flaw in your reasoning. That is the time it takes for a message to get from sender to receiver. That time can never be less than zero because there will always be a distance covered. So if it takes 10 seconds for a luminal signal to traverse from Bob to Alice, then a superluminal message sent at 2c will take half the time, not negative time. All you are doing is further dividing the distance by the rate which will give you ever decreasing time it takes for the message to reach it's destination, never giving you a negative number (going back in time). It is a funny conversation but unfortunately not an accurate portrayal of our universe.
That being said, this isn't a endorsement of speeds greater than that of light, just that superluminal messaging isn't a solid argument against it.
JakeStan said:Well the problem with our superluminal communication argument negating free will is contextual. That is you are using our intuition to disregard a flaw in your reasoning. That is the time it takes for a message to get from sender to receiver. That time can never be less than zero because there will always be a distance covered. So if it takes 10 seconds for a luminal signal to traverse from Bob to Alice, then a superluminal message sent at 2c will take half the time, not negative time. All you are doing is further dividing the distance by the rate which will give you ever decreasing time it takes for the message to reach it's destination, never giving you a negative number (going back in time). It is a funny conversation but unfortunately not an accurate portrayal of our universe.
That being said, this isn't a endorsement of speeds greater than that of light, just that superluminal messaging isn't a solid argument against it.
I do not see how you can conclude Backwards or Forwards motion in time without make assumptions outside the rules of SR Simultaneity. You will need to be much more detailed to show how you do that.kev said:You claim that I am "making unfounded conclusions about reality based on assumptions on what would happen if you built such a system". ...
I made a conclusion not an implication.Your response suggests you have a clear idea of what superluminal communications implies, but you have not made it clear what exactly you think it does imply. ...
Why would you only half expect that?I half expected I would be accused of selectively using reference frames because I was being lazy to keep the explantion brief and perhaps I could have been clearer. I will break down the explanation further here to try and make my reasoning clearer.
Alice sends a superluminal signal to Bob at 2c in her reference frame.
In Bob's reference frame, Alice is going away from him at 0.9c and from Bob's point of view, her signal appears to be going from the future to the past. This is a simple Lorentz transformation. ...
No, not without violating the Simultaneity Rule at least once maybe twice more.We can now do it all just in Alice's reference frame.
But you didn’t use just Alice’s clock you used other clocks as preferred to show events as moving forward or backwards with respect to Alice’s clock then switched back to Alice’s clock as preferred.I agree. That is why I suggested only using Alice's clock. The events "sending query" and "receiving reply" happen in the same location and the order of those events is determined by one single stationary clock (Alice's) so that no ambiguity of the simultaneity of spatially separated events is involved.Simultaneity says the only time you can know two events are actually simultaneous is when they happen physically spatially next to each other.
JakeStan said:Doesn't the Lorentz Transformation include c in it in the form of the Lorentz Factor? That would be using an argument that already accepts c as the limit of velocity in the universe to prove that nothing can go faster than c. Then it becomes an argument of terms, when you say "you can't have superluminal messaging because it eliminates free will and causality" and then cite the Lorentz Transformation you are really saying "you can't have superluminal messaging because c is the speed limit of the universe". I would agree to the latter point but the prior is an extra step in rationale that is unnecessary.
JakeStan said:Edit: Also, thanks for the welcome, I'm really enjoying the site so far and please forgive any faults in my form or etiquette!
No authority can support that case without violating the Simultaneity Rule.kev said:IF FLT communications are allowed by nature THEN causality is violated/reversed
I have tried to show why this is the case in the diagrams and calculations of my previous posts, so now I will have to resort to an appeal to authority to make my case.
JakeStan said:I think we are agreeing here, I don't believe that FLT communications are possible but only because I believe that the speed of light is the speed limit of the universe. My point was more that the causality and free will argument is hollow because it uses the speed of light as a given to present the argument. A way to look at it is if you chance c in the Lorentz Factor to 1/2c then you use c for any communications in the examples, you can prove that luminal communication would give you negative time and imply free will and causality do not exist. It is using word in its own definition.
Again, I'm not trying to use this as an argument for FTL communications, just that if you were ever to break down the speed of light (thus changing how the Lorentz Transformation works) you could have FTL communications but it would be moot because you've already gone past the speed of light anyways!
There is no flaw in kev's reasoning, but a hidden assumption: if the principle of relativity still holds, superluminal speed implies time travel.That is you are using our intuition to disregard a flaw in your reasoning.
Galileo’s principle of relativity will still hold without implying time travel IF you hold to Special Relativity Principles like the Simultaneity Rule.Ich said:There is no flaw in kev's reasoning, but a hidden assumption: if the principle of relativity still holds, superluminal speed implies time travel.
Can you please explain exactly what you mean by "the Simultaneity Rule"? This isn't standard terminology.RandallB said:Galileo’s principle of relativity will still hold without implying time travel IF you hold to Special Relativity Principles like the Simultaneity Rule.
Violating the Simultaneity Rule is the flaw that allows the illusion of causality violations that imply “time travel”.
See post #20DrGreg said:Can you please explain exactly what you mean by "the Simultaneity Rule"? This isn't standard terminology.
There is no Galileo's principle of relaitvity nor an Einsteinian one. There is a Principle of relativity which states that you can't find a preferred frame by whatever intrinsic measurement you do, and that means that speed be defined relative to the observer, not to a preferred frame. Especially talking about FTL, in the easiest case of infinite speed, this can only mean along the observer's line of simultaneity, as no other definition can be given. The "SR rules" concerning simultaneitiy are the only ones compliant with the principle of relativity.Galileo’s principle of relativity will still hold without implying time travel IF you hold to Special Relativity Principles like the Simultaneity Rule.
The “special principle of relativity” was established by Galileo 1639Ich said:There is no Galileo's principle of relaitvity nor an Einsteinian one.
RandallB said:The problem I see is so many that think they know SR, somehow believe SR Simultaneity gives them permission to use any arbitrary frame as preferred.
RandallB said:The Einstein SR Simultaneity Rule is clear, no frame of synchronization is to be trusted to define Simultaneous.
Ok.The “special principle of relativity” was established by Galileo 1639
When you used both “Bob's point of view” and “Alice's point of view” as reliable to judge distant event synchronizations (causality) you did not just define a preferred frame, you used two of them!kev said:I am not sure where you think I selected a reference frame as preferred.
You claimed:Ich said:Ok.
And how does this fit with a preferred frame? Not CMB matter, but different laws of physics, i.e. different tachyonic speeds depending on orientation and absolute state of motion?