Warp - any scientific take on it?

[Jon Miller]

I am starting to be reminded of quarters.

JM

[Kuciwalker]

It's not a quarter, it's syrup.

[Ramo]

George, start with the basics. Read Einstein's 1905 paper on Relativity. It's well-written (and well-translated), insightful, etc. He starts with Maxwell, notes that the equations are valid in any inertial reference frame. Thus, the vacuum electromagnetic wave equation (combine the two curl equations) is valid in any inertial reference frame. And he probably references Michelson-Morley. Thus, the speed of light is the same in any inertial reference frame. And the Lorentz transformations follow naturally from that. Get to work.

[KrazyHorse]

Originally posted by Kuciwalker
The point being that the Lorentz tranformation applies even though everything is "isntantaneous" and nothing moves.

Only in one frame of reference...

[Perfection]

And so the lesson is, if you find a big deposit o' Naqahdah, you can build a stargate, AND a time machine!

[Kuciwalker]

Not if a stargate acts like a wormhole.

[KrazyHorse]

Originally posted by TCO
What leg of the journey did it creep in? As far as I see, we stake out a cartesian grid on the universe. We can now consider each step of the "round the block" transmission and for each event (msg initiated or recievied) write down exactly what point each ABCD is at in terms of the grid

In which frame of reference, dude?

There are only 3 relevant "events":

1) The point where A sends the signal
2) The point where B receives the signal/C sees B receiving signal/C sends signal
3) The point where D receives the signal/A sees D receiving signal

The reason 2 and 3 are each one event is that everything listed in them happens at the exact same point in space and time.

There are 4 frames of reference: A,B,C and D

We thus have 12 relevant 4-vectors: 1A, 3C, 2D etc.

4-vector convention (t,x,y,z)

Here they are:

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)

As you can see, C and D already notice a problem from event 1 to event 2. The observed time for A to send signal is before the observed time for B to get it. A and B don't yet notice a problem. If you were naive, you might assume that this is merely some sort of theoretical problem. Nobody has any knowledge of their own future yet. But this problem is real.

Then, from even 2 to event 3 is where things get really weird. C and D are fine with this transmission. A and B are not. Again, you might want to assume that the problem is merely an artifact of the theory. The problem with that is that by linking the two problematic transmissions together into a loop you've brought news of A's future back to A.

In the rest frame of sender and receiver there is no causality problem with anything they send. The causality problem creeps in when you look at your two buddies sending messages to each other as they travel at the same velocity relative to you.

[KrazyHorse]

Here is a diagram representing the transmissions from A and B's point of view. Arrows go in direction of transmissions. Red is event 1, blue is event 2 and green is event 3.

[KrazyHorse]

Same thing, from C and D's point of view

[Geronimo]

Originally posted by Kuciwalker
Not if a stargate acts like a wormhole.

Look. unless the two openings of a wormhole are at rest with respect to each other (and not experiencing any major differences in gravitational fields) you are certainly going to have some time travel effects. 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).

[KrazyHorse]

You don't have a clue what you're talking about.

[Geronimo]

Originally posted by KrazyHorse
You don't have a clue what you're talking about.

KH are you saying that if a wormhole has one end accelerated to 0.99c with respect to the other end that the clocks at each end would remain in agreement?

Furthermore, suppose you go through the wormhole when the clocks do not agree (as seen from an external observer).

Do you agree that the clocks will in fact agree when you go through the wormhole in either direction?

The ends aren't moving with respect to each other through the wormhole, only externally (ie not through it). They share an internal frame of reference while having seperate external frames of reference.

So when you look through the wormhole at the clock on the other side it always agrees even though if you look at the clock via some other path that doesn't go through the wormhole the accelerated clock lags the other clock.

So an external observer accelerates up to the accelerated wormhole where it's calendar is only say january 2005, looks through the wormhole at the unaccelerated calendar which also says January 2005, looks over his shoulder (the long way) at that same unaccelerated clock which shows the present time (minus some time for light transit) and walks through the wormhole into january 2005.

This all depends on the idea that when one wormhole opening is accelerated relative to the other that this does not change the frame of reference established through the wormhole.

[Geronimo]

I wonder if KH thinks Kip thorne is a hack.

[KrazyHorse]

Originally posted by Geronimo


KH are you saying that if a wormhole has one end accelerated to 0.99c with respect to the other end that the clocks at each end would remain in agreement?

No.

[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).