Warp - any scientific take on it?

[KrazyHorse]

Originally posted by TCO
Yeah, but there is no way for them to know it happened and to really deliver a message back in time to myself. Kust some messed up doiagrams.

I just told you how to do it...if you're allowed to cross light cones by sending FTL messages

The light cones are what guard causality in SR. Cross them at your peril.

[Geronimo]

Originally posted by KrazyHorse
Relativity breaks simultaneity. If A and B have set stopwatches so that they perform same action at what they observe to be same time, then C and D will observe them performing that action at different times

So if we imagine big visible clocks at each person and the signal being perhaps an instantaneous transmission closed circuit camera-TV link between A and B which allows for seeing B with B's clock at A and seeing A with A's clock at B how will the apparent signal propagation backward in time present itself to D? At events R and event P will the same time be visible on the TV at A? Will A not see the same screen as D does when event R occurs?

[KrazyHorse]

Originally posted by Geronimo


So if we imagine big visible clocks at each person and the signal being perhaps an instantaneous transmission closed circuit camera-TV link between A and B which allows for seeing B with B's clock at A and seeing A with A's clock at B how will the apparent signal propagation backward in time present itself to D? At events R and event P will the same time be visible on the TV at A? Will A not see the same screen as D does when event R occurs?

At event R, A is getting three signals. He has his clock in ship, he is getting B's clock FTL, and he is looking at his own clock from ABCDA loop. B's clock always reads the same as his own clock in his ship, but the clock he's looking at from ABCDA loop (his own clock) is from 5 minutes in future.

[Geronimo]

Originally posted by KrazyHorse


At event R, A is getting three signals. He has his clock in ship, he is getting B's clock FTL, and he is looking at his own clock from ABCDA loop. B's clock always reads the same as his own clock in his ship, but the clock he's looking at from ABCDA loop (his own clock) is from 5 minutes in future.

Ok so he could watch himself "realtime" 5 minutes into the future by watching the screen from the ABCDA loop.


that does seem pretty causality shredding.

[KrazyHorse]

Errrr...yeah.

[Geronimo]

Originally posted by KrazyHorse
Errrr...yeah.

do you expect further elaboration on exisiting understanding of relativity to eventually make wormholes not only practically impossible but theoretically impossible as well? It doesn't seem as if the causality loss could be avoided for any stable wormhole under any circumstances.

[Kuciwalker]

Wormholes are a product of GR, not SR.

[Geronimo]

Originally posted by Kuciwalker
Wormholes are a product of GR, not SR.

yes

[KrazyHorse]

Originally posted by Geronimo


do you expect further elaboration on exisiting understanding of relativity to eventually make wormholes not only practically impossible but theoretically impossible as well? It doesn't seem as if the causality loss could be avoided for any stable wormhole under any circumstances.

Actually, the existence of a stable wormhole leading between A and B would wreck the previous causality argument.

AFAICS there's no obvious reason to rule out wormholes due to a causality argument.

[Perfection]

Originally posted by Joseph
Read this.

That's group velocity, which doesn't transfer info FTL. Things can travel FTL as long as they don't transfer information.

So realy, nothing gained here, blame sensationalist media.

Originally posted by KrazyHorse AFAICS there's no obvious reason to rule out wormholes due to a causality argument.

If you can use womholes for FTL, you can use them for time travel.

[Geronimo]

Originally posted by KrazyHorse


Actually, the existence of a stable wormhole leading between A and B would wreck the previous causality argument.

AFAICS there's no obvious reason to rule out wormholes due to a causality argument.

Ok, So if in place of a worm hole A and B are connected by an instantaneous transmission closed circuit cable so that there is no ABCDA loop comparible to the causality wrecking one in the first example, there is no longer any way for any of the persons A, B, C, D to obtain information from their future?

[Perfection]

Originally posted by Geronimo


Ok, So if in place of a worm hole A and B are connected by an instantaneous transmission closed circuit cable so that there is no ABCDA loop comparible to the causality wrecking one in the first example, there is no longer any way for any of the persons A, B, C, D to obtain information from their future?

Throw the edge of wormhole B near some handy source of high gravity and watch as the at the aperatures move out of sync.

You can do the same thing with acceration too!





Of course, the whole wormhole thing is pretty flakey. Good luck getting your hands one!

[FrostyBoy]

This thread makes my eyes go crosseyed.

[Perfection]

Originally posted by Sn00py
This thread makes my eyes go crosseyed.

Makes your eyes go crosseyed? As opposed to you ears going crosseyed?

[Geronimo]

Originally posted by Perfection
Throw the edge of wormhole B near some handy source of high gravity and watch as the at the aperatures move out of sync.

You can do the same thing with acceration too!





Of course, the whole wormhole thing is pretty flakey. Good luck getting your hands one!

In the scenario you quoted there was no wormhole.

In any event I already acknowledged the practical objections to wormholes. This was addressing possible theoretical objections to wormholes being expected as a consequence of current trends in phyics. That is to say I was asking if its expected that large scale wormholes will be found to not be even theoretically possible.