Warp - any scientific take on it?

[Geronimo]

Originally posted by KrazyHorse
I also don't know enough about Kip Thorne's work to offer a meaningful opinion on it.

And you don't know anything at all about general relativity, which led you to make this ridiculous statement:

It's just that unless one end is moving at relativistic velocity relative to the other or unless the difference in gravitational environment are huge those effects will be undramatic. (ie one end of the wormhole will be a few milliseconds in the past relative to the other).

'Ridiculous' as in vague sure. but the sense that a non large (ie small) acceleration of one end will make for a negligable difference in time effects is essentially parroting what kip thorne had said.

I need some help teasing away the most ridiculous bits.

Does it make no difference how much one opening is accelerated in relation to the other?

Where wormholes aren't involved my total lack of understanding whatsoever of SR and GR tells me that a pair of clocks will desynchronize if one is accelerated relative to another such that the accelerated clock will lag the unaccelerated clock.

Ridiculous?

Where wormholes aren't involved my cluelessness also informs me that a clock subjected to gravitational time dilation will also lag relative to the other clock.

Ridiculous?

My ignorant mutilation of GR further informs me that the difference in proper time for two observers is negligable but not zero for many possible values of distance and M.

Is that ridiculous?

[edit actually I now see the wording was criminally poor for what I was trying to say, but I still can't see where it went to ridiculous]

[TCO]

1. I'm supposed to be banned, so that I can be a corporate shmuck and succeed at that.

2. 3 is not all happening at the same point/time, since D is already past A, when A sends his message.

[Geronimo]

Originally posted by KrazyHorse


No.

This might be the rub. As Kip Thorne asserted it wasn't as simple as that. They wouldn't agree to an external observer but would agree by any means of measurement that traverssed the wormhole to compare them.

[KrazyHorse]

Originally posted by TCO
1. I'm supposed to be banned, so that I can be a corporate shmuck and succeed at that.

2. 3 is not all happening at the same point/time, since D is already past A, when A sends his message.

D is past A when A sends the message.

D is at A when he receives the message. This happens before A sends the message

Are you deliberately messing with me?

[TCO]

Originally posted by KrazyHorse


D is past A when A sends the message.

D is at A when he receives the message. This happens before A sends the message

Are you deliberately messing with me?

No. I really am this stupid. How can D be back at A? It's later.

The smiley was for effect, but I really am not teasing.

[Geronimo]

KH would you have easy access to:

F. Echeverria, G. Klinkhammer and K.S. Thorne, "Billiard Balls in Wormhole Spacetimes with Closed Timelike Curves: I. Classical Theory," Physical Review D, 44, 1077-1099 (1991).

All I have is a print copy atm.

Would you even be interested in a physicist making the bald faced claim that time travel is an almost inevitable consequence of any stable worm hole?

That paper seems to be where he first examines the problem.

[KrazyHorse]

Seriously, dude. It's like you're being ridiculously bull-headed. You've got an a priori idea that D must receive the message after A sends it, despite the fact that I've provided incontrovertible proof that this is untrue.

Instead of learning the theory yourself you've asked me to explain certain aspects of the problem to you. I did this by providing the coordinates of all events in all frames of reference.

Then you proceed to tell me that my coordinates must be wrong because they don't conform to your a priori assumption.

Your a priori assumption is wrong. Accept it. I'm not going to argue with you any more on this. If there are certain aspects you're uncomfortable with then feel free to ask me a question. But I'm not going to respond to any further assertions based on your preconceived notions about how things must work.

[KrazyHorse]

Originally posted by Geronimo


'Ridiculous' as in vague sure. but the sense that a non large (ie small) acceleration of one end will make for a negligable difference in time effects is essentially parroting what kip thorne had said.

I need some help teasing away the most ridiculous bits.

Does it make no difference how much one opening is accelerated in relation to the other?

Where wormholes aren't involved my total lack of understanding whatsoever of SR and GR tells me that a pair of clocks will desynchronize if one is accelerated relative to another such that the accelerated clock will lag the unaccelerated clock.

Ridiculous?

Where wormholes aren't involved my cluelessness also informs me that a clock subjected to gravitational time dilation will also lag relative to the other clock.

Ridiculous?

My ignorant mutilation of GR further informs me that the difference in proper time for two observers is negligable but not zero for many possible values of distance and M.

Is that ridiculous?

[edit actually I now see the wording was criminally poor for what I was trying to say, but I still can't see where it went to ridiculous]

What's really funny is that you still don't understand my objection.

I have not once claimed that accelerating one end of a wormhole would not have an effect on synchronisation, nor that small accelerations would have a small effect on synchronisation.

[TCO]

I agree you have been very patient.

Specific question: when C IMs the message to D, why do you think that will be to a D "back in time". I mean, if they have synchronized clocks and all (and are going same speed, so no time dilation issue, they really could have synched clocks. So when C is "at B". D is "past A". By the same clock that both of them hold?

Was this specific enough or enraging?

[KrazyHorse]

This is the transmission from C and D's point of view. In that frame the backwards in time happens on first leg. That's why it's angled downwards.

The second leg has no t component. That's why it's horizontal.

I've already said this a number of times.

The backwards in time happens, for C and D, on the first leg of journey.

For A and B it happens on second leg

[KrazyHorse]

So when C is "at B". D is "past A".

NOOOOOO!!!!!!

In the frame of reference of C and D, C is at B at the exact same moment that D is at A

1A = (0,0,0,0)
1B = (0,-d,0,0)
1C = (vd/c^2,-gd,0,0)
1D = (vd/c^2,-gd+d/g,0,0)

2A = (0,d,0,0)
2B = (0,0,0,0)
2C = (0,0,0,0)
2D = (0,d/g,0,0)

3A = (-vd/c^2,0,0,0)
3B = (-vd/c^2,-d,0,0)
3C = (0,-d/g,0,0)
3D = (0,0,0,0)

C is at B when B gets message. This is event 2

2C = (0,0,0,0)
2D = (0,d/g,0,0)

in both cases t = 0

Now, D is at A when D gets message. This is event 3

3C = (0,-d/g,0,0)
3D = (0,0,0,0)

There is no time component to displacement vector from 2 to 3 in these frames

So, in C and D's frames, the occurence of C passing B and D passing A are simultaneous

BUT, in A and B's frames, let's see:

2A = (0,d,0,0)
2B = (0,0,0,0)
3A = (-vd/c^2,0,0,0)
3B = (-vd/c^2,-d,0,0)

So, in A and B's frame, C passing B and D passing A ARE NOT SIMULTANEOUS

SR breaks simultaneity!!!!

[Geronimo]

Originally posted by KrazyHorse


What's really funny is that you still don't understand my objection.

I have not once claimed that accelerating one end of a wormhole would not have an effect on synchronisation, nor that small accelerations would have a small effect on synchronisation.

when you calm down spell out your objection.

[edit and whatever you think of my posts so far I hope I haven't soured you on the paper by Kip Thorne. If you aren't already familier with his work on wormholes I can't imagine why it wouldn't interest you]

[KrazyHorse]

Read the damn coordinates, dude.

[KrazyHorse]

Originally posted by Geronimo


when you calm down spell out your objection.

I'm quite calm.

Please post the metric tensor for your postulated wormhole. Or, failing that, the curvature tensor.

[TCO]

But I thought you said in the very beginning, that D was past A, when the IMing started. How can D be past A at that time. But then be at A also?