Match 12141 The Star Wars Fanatics vs. Trekkies

[Guest force_echo]

FTL travel, if treated "realistically" would also result in time travel, and while Star Trek has time travel in it, it wouldn't be a special occasion type of deal, all FTL travel (again, if treated "realistically) results in time travel.

Unless it doesn't. FTL travel using a dark energy bubble wouldn't result in time travel because you're manipulating spacial distortion on a higher dimension. So if you were to create a bubble of dark energy and use that, it wouldn't result in time travel- realistically. Well realistically in the sense that the tech actually exists.

[Guest Ruinus]

Unless it doesn't. FTL travel using a dark energy bubble wouldn't result in time travel because you're manipulating spacial distortion on a higher dimension. So if you were to create a bubble of dark energy and use that, it wouldn't result in time travel- realistically. Well realistically in the sense that the tech actually exists.

 

It doesn't matter if the ship itself isn't actually "moving", moving through a wormhole, somehow magically gaining speed past c or any other method of FTL, the end result is that you arrive at your destination (let's say Alpha Centauri in this example) and you can look back at Earth and you're still there. You then turn your ship around and head back to Earth and you end up arriving before you've left.

[Guest Ruinus]

This page specifically mentions folding space or using some sort of warp drive. Again, all FTL travel methods "realistically" end up with time travel. It's based on real science, even if we don't know if there are some sort of extra level of physics in FTL-land, the end result is that you end up with objects appearing in realspace where they shouldn't be. So even if, say, the ship Lollipop Lane enters hyperspace/folds space/enters a wormhole and the rules of physics are different in that bubble of folded space, in hyperspace, or in folding the Universe like a piece of paper, when it stops doing that it ends up back in the normal mundane universe. And needless to say, the Universe looks at that ship and says "What the hell you aren't supposed to be here."

[Guest force_echo]

Except I'm not talking about folding space or a warp drive. The ship using the dark energy bubble would remain in our universe, it's just the bubble that manipulates the extra spacial dimensions of string theory. Dr. Gerald Cleaver at Baylor University says that this method of FTL travel wouldn't result in any causality errors or time dilation. You would simply go from one point to the next faster than light.

 

I read the diagram you linked, and for some reason, it assumes that you wouldn't use the same method FTL to transmit information between C and D, making the space-time diagram inapplicable again, and allowing the preservation of causality.

[Guest Ruinus]

Except I'm not talking about folding space or a warp drive. The ship using the dark energy bubble would remain in our universe, it's just the bubble that manipulates the extra spacial dimensions of string theory. Dr. Gerald Cleaver at Baylor University says that this method of FTL travel wouldn't result in any causality errors or time dilation. You would simply go from one point to the next faster than light.

 

Link 1

Link 2

 

Post the one where he says it won't cause time travel, because as I understand it any movement at FTL speeds (no matter the method) causes time travel.

 

I read the diagram you linked, and for some reason, it assumes that you wouldn't use the same method FTL to transmit information between C and D, making the space-time diagram inapplicable again, and allowing the preservation of causality.

 

I assume you are talking about diagram 9.1?

If so, then:

• e) An observer at C sends an FTL signal to D. Since the space-time between C and D need not be effected by the bullet's FTL travel, our space-time diagrams can be applied.
  

[Guest Hayesmeister5651]

To the issue of getting married as a Jedi; It is against the Jedi order. That is why Anakin did it secretly. it goes against the Jedi Code. Revan doing it in his time is just as bad as Anakin doing it. The Jedi are like monks, they don't live for themselves.

[C.T.]

Yet Luke Skywalker's marriage was very public.

[Guest Hayesmeister5651]

Yet Luke Skywalker's marriage was very public.

Meh, you said it yourself, his time as a Jedi is a lot different, considering he restarted the academy. I was mainly speaking in times of Anakin.

[Guest force_echo]

Yes, but that FTL signal is obviously not transmitted in the same way as the "bullet" in the example because they don't discontinue the space-time diagram. They're assuming that information and massive particles are being transmitted through different coordinates. In fact, that very example posits that FTL travel will NOT cause time travel, but that information transmitted via a third observer to the "shooter" will violate causality. There's a difference there, the bullet in that example isn't travelling through time at all.

[Guest force_echo]

To the issue of getting married as a Jedi; It is against the Jedi order. That is why Anakin did it secretly. it goes against the Jedi Code. Revan doing it in his time is just as bad as Anakin doing it. The Jedi are like monks, they don't live for themselves.

Except that Revan didn't hide his marriage at all. And not only did the Jedi Council not exile him or whatever, they made him a member of the Council.

[Guest Hayesmeister5651]

Except that Revan didn't hide his marriage at all. And not only did the Jedi Council not exile him or whatever, they made him a member of the Council.

Inconsistent writing. The secret romance between Anakin and Padame was a plot point in Episode 2 and 3.

[Guest force_echo]

Because Anakin was already on watch. The Council was already suspicious. Marriage would be the "strike 3" for Anakin so to speak.

[Guest Ruinus]

Yes, but that FTL signal is obviously not transmitted in the same way as the "bullet" in the example because they don't discontinue the space-time diagram. They're assuming that information and massive particles are being transmitted through different coordinates.

 

The transmission method doesn't matter.

• It is important to note that the real crux of this problem does not come from the form of the FTL travel used, but from the relationship between the two, ordinary frames of reference for observers (O and Op) who never themselves travel FTL.
  

In fact, that very example posits that FTL travel will NOT cause time travel, but that information transmitted via a third observer to the "shooter" will violate causality. There's a difference there, the bullet in that example isn't travelling through time at all.

 

No it doesn't, it flat out states that causality is violated.

• The above events show that even though the space-time may be changed between A and B during the bullet's trip, the O observer can still know about and use the fact that the victim was killed in order to prevent the victims death. We use the same arguments we did in the section concerning the "second problem" ( Section 9.1 ), except that the two FTL portions (the bullet and the signal from the third observer) are sent from two different locations so that neither is affected by the other's effects on space-time. Thus, as long as there are no special provisions, this form of FTL travel will still allow for unsolvable paradoxes.
  

A violation of causality IS time travel. The information is coming from the future in the frame of reference of the guy standing next to the fool who gets shot.

 

Also, you are wrong, Diagram 8-1, uses the same example (but a different diagram) of the example in diagram 9-1. This is laid out in Section 8.3 with the followoing:

• The bullet strikes and kills a victim who's death is the event marked "*" in Diagram 8-1 . This event occurs after the passing event in Op's frame of reference, but it occurs before the passing event in O's frame.
  

You could replace the bullet with a pod carrying a person and the end result is the same, the pod carrying a person in it is arriving from the future in someone's frame of reference. It doesn't matter what (or how) the object is traveling FTL, it could be a message, a pod carrying someone, a ship, a baseball, if it's moving FTL somehow, it's violating causality. Violating causality means it's appearing before the "natural" order of events.

[Guest force_echo]

The transmission method doesn't matter.

• It is important to note that the real crux of this problem does not come from the form of the FTL travel used, but from the relationship between the two, ordinary frames of reference for observers (O and Op) who never themselves travel FTL.
  

 

No it doesn't, it flat out states that causality is violated.

• The above events show that even though the space-time may be changed between A and B during the bullet's trip, the O observer can still know about and use the fact that the victim was killed in order to prevent the victims death. We use the same arguments we did in the section concerning the "second problem" ( Section 9.1 ), except that the two FTL portions (the bullet and the signal from the third observer) are sent from two different locations so that neither is affected by the other's effects on space-time. Thus, as long as there are no special provisions, this form of FTL travel will still allow for unsolvable paradoxes.
  

A violation of causality IS time travel. The information is coming from the future in the frame of reference of the guy standing next to the fool who gets shot.

 

Also, you are wrong, Diagram 8-1, uses the same example (but a different diagram) of the example in diagram 9-1. This is laid out in Section 8.3 with the followoing:

• The bullet strikes and kills a victim who's death is the event marked "*" in Diagram 8-1 . This event occurs after the passing event in Op's frame of reference, but it occurs before the passing event in O's frame.
  

You could replace the bullet with a pod carrying a person and the end result is the same, the pod carrying a person in it is arriving from the future in someone's frame of reference. It doesn't matter what (or how) the object is traveling FTL, it could be a message, a pod carrying someone, a ship, a baseball, if it's moving FTL somehow, it's violating causality. Violating causality means it's appearing before the "natural" order of events.

I don't think you understand either their example or what I'm saying. The third observer sends a FTL transmission back to O, but this transmission is not treated in the same way as the bullet, which was able to travel to the target without causing a violation. The second FTL transmission is going back in time, when it really shouldn't be, since the bullet didn't. they're not discontinuing the space time coordinate in the second example like they're doing with the first, therefore whoever this is must be assuming that the method by which the bullet traveled and the method by which the information traveled is different.

 

Violation of causality isn't time travel, it just requires time travel. Again, if you actually read what they're saying, the whole point of their experiment is that the bullet itself hits the person without travelling backwards in time. In that example, the person is still assuming that while travelling FTL (O), you would be at a different frame than another person travelling FTL (OP). They're not assuming that the frames of reference between O,OP, and * are all the same as they did in the other example. This is because this example is without the warping of space time between O, OP, or 3rd observer, as they say themselves space time is assumed to be flat. In the other example you linked, space time was expected to be warped, but the problem is, in the FTL transmission of the signal, the space time was NOT expected to be warped.

[Guest Ruinus]

I don't think you understand either their example or what I'm saying. The third observer sends a FTL transmission back to O, but this transmission is not treated in the same way as the bullet, which was able to travel to the target without causing a violation. The second FTL transmission is going back in time, when it really shouldn't be, since the bullet didn't. they're not discontinuing the space time coordinate in the second example like they're doing with the first, therefore whoever this is must be assuming that the method by which the bullet traveled and the method by which the information traveled is different.

 

 

 

1. The bullet strikes and kills a victim who's death is the event marked "*" in Diagram 8-1 . This event occurs after the passing event in Op's frame of reference, but it occurs before the passing event in O's frame.
   

You need to re-read that section, the FTL bullet is still following the 8.1 diagram, hitting the person at B at event *. The point of diagram 9.1 is that the bullet is traveling backwards in time to hit someone at event * will skew the above pictured diagram for O and Op, but that other observes (in their own frame) can still use FTL to tell O about Op shooting someone at event * to prevent it.

 

Violation of causality isn't time travel, it just requires time travel. Again, if you actually read what they're saying, the whole point of their experiment is that the bullet itself hits the person without travelling backwards in time. In that example, the person is still assuming that while travelling FTL (O), you would be at a different frame than another person travelling FTL (OP). They're not assuming that the frames of reference between O,OP, and * are all the same as they did in the other example. This is because this example is without the warping of space time between O, OP, or 3rd observer, as they say themselves space time is assumed to be flat. In the other example you linked, space time was expected to be warped, but the problem is, in the FTL transmission of the signal, the space time was NOT expected to be warped.

 

Something that requires time travel is time travel. :|

Again, you are wrong. Diagram 8.1 (from which all the following ones are based on) specifically points out how the FTL bullet is time traveling from the common event (the passing event) to hit someone in Os past even though the firing of the gun takes place in the "present".

What? Not a single example has everyone's frame of reference being the same. All the diagrams have the frame of reference being different for O and Op.

No, Diagram 9.1 specifically states an example where the FTL bullet warps spacetime between O and Op (again, since it refers back to Diagram 8.1) invalidates the diagram for 8.1 but that the 3rd observers (who's spacetime isn't warped) can send messages back to O to warn him about event *.

[Guest force_echo]

1. The bullet strikes and kills a victim who's death is the event marked "*" in Diagram 8-1 . This event occurs after the passing event in Op's frame of reference, but it occurs before the passing event in O's frame.
   

You need to re-read that section, the FTL bullet is still following the 8.1 diagram, hitting the person at B at event *. The point of diagram 9.1 is that the bullet is traveling backwards in time to hit someone at event * will skew the above pictured diagram for O and Op, but that other observes (in their own frame) can still use FTL to tell O about Op shooting someone at event * to prevent it.

 

 

 

Something that requires time travel is time travel. :|

Again, you are wrong. Diagram 8.1 (from which all the following ones are based on) specifically points out how the FTL bullet is time traveling from the common event (the passing event) to hit someone in Os past even though the firing of the gun takes place in the "present".

What? Not a single example has everyone's frame of reference being the same. All the diagrams have the frame of reference being different for O and Op.

No, Diagram 9.1 specifically states an example where the FTL bullet warps spacetime between O and Op (again, since it refers back to Diagram 8.1) invalidates the diagram for 8.1 but that the 3rd observers (who's spacetime isn't warped) can send messages back to O to warn him about event *.

I need to reread it? You're the one using a completely different graph for the example. First of all, occuring at different times for different frames =/= time travel, otherwise any speed up to light speed would be time travelling. Just because O and O prime see the bullet firing at different intervals, before or after the passing event, does not mean the bullet is travelling backwards in time. No, the point of 9.4 is that space time is being warped so that "the ship's clock [keeps] ticking just as it would have if the ship remained "stationary" (in it's original frame of reference)". Like I said before, 8.1 does not assume this at all.

 

The bullet itself is not travelling backwards in time, the problem is that the person says that you can warn someone about the bullet before it's fired using FTL communication- which is a violation of causality. I repeat, this is different that the bullet going backwards in time. In 9.4, A shoots B and the bullet remains in the same reference. That's what I meant, i.e- the bullet is not travelling backwards in time. The 3rd observer can warn A about the event before it happens because while the information the 3rd observer has is being sent FTL, it's not warping time, it's not following the same rules as the bullet, they're not invalidating the space-time chart.

 

Massive derailment?

[Guest Ruinus]

I need to reread it? You're the one using a completely different graph for the example. First of all, occuring at different times for different frames =/= time travel, otherwise any speed up to light speed would be time travelling. Just because O and O prime see the bullet firing at different intervals, before or after the passing event, does not mean the bullet is travelling backwards in time. No, the point of 9.4 is that space time is being warped so that "the ship's clock [keeps] ticking just as it would have if the ship remained "stationary" (in it's original frame of reference)". Like I said before, 8.1 does not assume this at all.

 

Diagram 9.1 specifically references points on Diagram 8.1, it specifically references the FTL bullet going back and killing someone at event * on diagram 8.1 so yes, you clearly do need to read that section again since you seem to think diagram 9.1 is whole self contained and on its own when it isn't. Otherwise you wouldn't be making statements such as "the bullet didn't go back in time" when the entire point of that diagram is that the bullet did, in fact, go back in time.

 

Did I claim that events occuring at different orders in different frames equal time travel? No, I didn't. Also, where in the text does it say that simply because O and Op see the bullet firing at different intervals does that mean the bullet time traveled? Nowhere. In fact it specifically states that this is normal:

 

Normally, this fact gives us no trouble. If you draw a light cone (as discussed in Section 2.8 ) through the origin, then the event will be outside of the light cone. As long as no signal can travel faster than the speed of light, then it will be impossible for either observer to know about or influence the event. So even though it is in one observer's past, he cannot know about it, and even though it is in the other observer's future, he cannot have an effect on it. This is how relativity saves its own self from violating causality.

 

It then also goes on to state how this would cause time traveling causality shenanigans.

 

However, consider the prospect of FTL travel with this diagram in mind. As O and Op pass by one another, the event "*" has not happened yet in Op's frame of reference. Thus, if he can send an FTL signal fast enough, then he should be able to send a signal (from the origin) which could effect "*". However, in O's frame, "*" has already occurred by the time O and Op pass by one another. This means that the event "Op sends out the signal which effects *" occurs after the event which it effects, "*", in O's frame. For O, The effect precedes the cause. Thus, the signal which travels FTL in Op's frame violates causality for O's frame. Similarly, since "*" has already occurred in O's frame when O and Op pass one another, then in his frame an FTL signal could be sent out from "*" which could reach O and tell him about the event as the two observer's past. However, for Op, the event "O learns about * as O and Op pass one another" comes before * itself. Thus, the signal which is FTL in O's frame violates causality in Op's frame.

 

No, that isn't the point of diagram 9.1, the point of diagram 9.1 is:

Both of these concepts get around the light speed barrier problem, but again we will argue the case for the problems with unsolvable paradoxes.

 

This is stated again at the end of that section:

The above events show that even though the space-time may be changed between A and B during the bullet's trip, the O observer can still know about and use the fact that the victim was killed in order to prevent the victims death. We use the same arguments we did in the section concerning the "second problem" ( Section 9.1 ), except that the two FTL portions (the bullet and the signal from the third observer) are sent from two different locations so that neither is affected by the other's effects on space-time. Thus, as long as there are no special provisions, this form of FTL travel will still allow for unsolvable paradoxes.

 

The bullet itself is not travelling backwards in time, the problem is that the person says that you can warn someone about the bullet before it's fired using FTL communication- which is a violation of causality. I repeat, this is different that the bullet going backwards in time. In 9.4, A shoots B and the bullet remains in the same reference. That's what I meant, i.e- the bullet is not travelling backwards in time. The 3rd observer can warn A about the event before it happens because while the information the 3rd observer has is being sent FTL, it's not warping time, it's not following the same rules as the bullet, they're not invalidating the space-time chart.

 

Massive derailment?

 

Again I'll quote the text, where it says the bullet does go back in time:

I'll illustrate the point with an example (again referring to Diagram 8-1 ) Remember we said that as O and Op pass, Op can send an FTL message out (from his frame of reference) which effects "*". However, rather than having him send a message out, let's say that Op sends out a bullet that travels faster than the speed of light. This bullet can go out and kill someone light-years away in only a few hours (for example) in Op's frame of reference. So, say he fires this bullet just as he passes by O. Then the death of the victim can be the event (*). Now, in O's frame of reference, the victim is already dead ("*" has occurred) when Op passes by. This means that another observer (stationary in O's frame) who was at the position of the victim when the victim was shot could have sent an FTL signal just after the victim's death, and that signal could reach O before Op passed by him. So O can know that Op will shoot his gun as they pass each other.

 

So from O's reference, some guy got shot at event *, but the shooting doesn't occur until hours later.

 

The bolded part from your quote is what seems to be wrong. The bullet moving from A to B in diagram 9.1 is actually an overlay of it's path from Ops 0x0y center in diagram 8.1, from his center of axis to event * (which is in Ops future but in Os past). As I said before, diagram 9.1 is part of diagram 8.1, only with the added assumption that the bullet is warping spacetime along it's path.

[Guest force_echo]

Diagram 9.1 specifically references points on Diagram 8.1, it specifically references the FTL bullet going back and killing someone at event * on diagram 8.1 so yes, you clearly do need to read that section again since you seem to think diagram 9.1 is whole self contained and on its own when it isn't. Otherwise you wouldn't be making statements such as "the bullet didn't go back in time" when the entire point of that diagram is that the bullet did, in fact, go back in time.

 

Did I claim that events occuring at different orders in different frames equal time travel? No, I didn't. Also, where in the text does it say that simply because O and Op see the bullet firing at different intervals does that mean the bullet time traveled? Nowhere. In fact it specifically states that this is normal:

 

Normally, this fact gives us no trouble. If you draw a light cone (as discussed in Section 2.8 ) through the origin, then the event will be outside of the light cone. As long as no signal can travel faster than the speed of light, then it will be impossible for either observer to know about or influence the event. So even though it is in one observer's past, he cannot know about it, and even though it is in the other observer's future, he cannot have an effect on it. This is how relativity saves its own self from violating causality.

 

It then also goes on to state how this would cause time traveling causality shenanigans.

 

However, consider the prospect of FTL travel with this diagram in mind. As O and Op pass by one another, the event "*" has not happened yet in Op's frame of reference. Thus, if he can send an FTL signal fast enough, then he should be able to send a signal (from the origin) which could effect "*". However, in O's frame, "*" has already occurred by the time O and Op pass by one another. This means that the event "Op sends out the signal which effects *" occurs after the event which it effects, "*", in O's frame. For O, The effect precedes the cause. Thus, the signal which travels FTL in Op's frame violates causality for O's frame. Similarly, since "*" has already occurred in O's frame when O and Op pass one another, then in his frame an FTL signal could be sent out from "*" which could reach O and tell him about the event as the two observer's past. However, for Op, the event "O learns about * as O and Op pass one another" comes before * itself. Thus, the signal which is FTL in O's frame violates causality in Op's frame.

 

No, that isn't the point of diagram 9.1, the point of diagram 9.1 is:

Both of these concepts get around the light speed barrier problem, but again we will argue the case for the problems with unsolvable paradoxes.

 

This is stated again at the end of that section:

The above events show that even though the space-time may be changed between A and B during the bullet's trip, the O observer can still know about and use the fact that the victim was killed in order to prevent the victims death. We use the same arguments we did in the section concerning the "second problem" ( Section 9.1 ), except that the two FTL portions (the bullet and the signal from the third observer) are sent from two different locations so that neither is affected by the other's effects on space-time. Thus, as long as there are no special provisions, this form of FTL travel will still allow for unsolvable paradoxes.

 

 

 

Again I'll quote the text, where it says the bullet does go back in time:

I'll illustrate the point with an example (again referring to Diagram 8-1 ) Remember we said that as O and Op pass, Op can send an FTL message out (from his frame of reference) which effects "*". However, rather than having him send a message out, let's say that Op sends out a bullet that travels faster than the speed of light. This bullet can go out and kill someone light-years away in only a few hours (for example) in Op's frame of reference. So, say he fires this bullet just as he passes by O. Then the death of the victim can be the event (*). Now, in O's frame of reference, the victim is already dead ("*" has occurred) when Op passes by. This means that another observer (stationary in O's frame) who was at the position of the victim when the victim was shot could have sent an FTL signal just after the victim's death, and that signal could reach O before Op passed by him. So O can know that Op will shoot his gun as they pass each other.

 

So from O's reference, some guy got shot at event *, but the shooting doesn't occur until hours later.

 

The bolded part from your quote is what seems to be wrong. The bullet moving from A to B in diagram 9.1 is actually an overlay of it's path from Ops 0x0y center in diagram 8.1, from his center of axis to event * (which is in Ops future but in Os past). As I said before, diagram 9.1 is part of diagram 8.1, only with the added assumption that the bullet is warping spacetime along it's path.

Except 9.1 is the same situation, but completely different, because the method of FTL travel is different. Except it didn't go back in time. At all. Nowhere does it say the bullet went back in time. The whole freaking postulation of 9.3 is that the bullet did NOT go back in time. You said that because the bullet occurs before or after an event in different frames of reference, those of O and O prime, that the bullet is FTL. That is specifically what you bolded. So yes, you did say that.

 

Again, the method used to warn the shooter before the shot is made (and causing the causality violation) is not using the method the bullet used, because in the bullet use, they made the condition that the bullet did not occur on a different frame of reference because it is violating space time. Again, this is literally the entire point of 9.3 and why it is different from 8.1. The bullet is warping space time along it's path, meaning that it retains the same frame as the person who shot it, meaning the bullet does not travel backwards in time, meaning it arrives "normally". Again, nowhere in 9.3 does it say the bullet traveled backwards in time, it is saying that a third person observer could warn the shooter before the shot using an FTL signal that does not warp space time. That's the problem.

[Guest Ruinus]

The bullet is warping space time along it's path, meaning that it retains the same frame as the person who shot it, meaning the bullet does not travel backwards in time, meaning it arrives "normally". Again, nowhere in 9.3 does it say the bullet traveled backwards in time, it is saying that a third person observer could warn the shooter before the shot using an FTL signal that does not warp space time.

 

The bullet retains Ops frame of reference, and in Ops frame of reference event * occurs in the future but in Os past.

[Guest force_echo]

The bullet retains Ops frame of reference, and in Ops frame of reference event * occurs in the future but in Os past.

The future as in the time it takes for the bullet to reach the target. Also, the event occurring in different places in different frames of reference is not evidence of time travel, it's just evidence of O and O prime being in different frames of reference.

[Guest captain Manzini]

Wow, a match I wrote started a discussion about the physics of time travel. Neat