I understand the basic concept of why nothing can move faster that light, but I don't believe that anything actually has to be moved.

I won't deny that this concept of this "ansible" comes from Orson Scott Card's "philotic web" but for the life of me I can't think of any reason why it wouldn't work.

Take a metal cylinder, it doesn't need to be wide, it may as well be a wire, as long as it won't bend. If you spin one end of it, the other end naturally spins.

Now, imagine that "wire" stretching for miles through space or across an ocean. I realize the material difficulties in such a venture over a period, but this is more of a theoretical proposition anyway. At each end of the wire there would be receptors which measure the degree of rotation, certain values corresponding to Unicode or something. The wire is spun in a certain direction a bit, spun the reverse direction a bit, etc.

Why is this impossible, or if it is possible, why hasn't it been done before?

Post has been edited 1 time(s), last time on Jul 2 2009, 4:39 am by FaZ-.

Well, this is a total guess based on my very VERY limited scientific knowledge. I believe that even though a solid is 'solid', all the molecules are individual, and they are just stuck together. Thus, when one piece of a solid moves, the whole thing doesn't actually move immediately, instead, I think there would be a delay.

Also, I think you can google this, and there's tons of explanations, not sure.

When you turn something elastic the same way, you see that it takes a second for one end to catch up to the other. That's what this would be like.

The only way I could see faster than light communication working is entanglement.

CAFG is right. Even though it may not seem... "Rubbery", the metal pole still has some elasticity. Something of that length would definately have a delay.
Besides, it's quite impractical to do, having a single pole go across the atlantic ocean, for a single connection.

How would connections move from party to party?
What If I want to call my friend who's down the street? Am I going to have to have a pole go to every single person I know?

The answer to this has really been provided already, and it lies in the speed of propogation of force. One good illustration of this would be something like the sun dissapearing. If it were suddenly removed from our solar system via
Remove Unit at Location("Sun", "The Solar System", 1);
what would we see? Well, since it takes light ~7 minutes to travel from the sun to earth, for another 7 minutes we would have normal sunlight and not know anything is wrong. But what about the gravitational pull? Would we fly out of our orbit for 7 minutes before we saw the sun dissapear? No, it appears that forces like gravity cannot travel faster than light speed either. Say you had a wire pole 1 light-second long. If you turn it a bit, it will take the intermolecular forces within the material (in a perfectly rigid body) the exact same length of time as it would take for the light to reach the end of the pole, 1 second. Unfortunately materials aren't perfectly rigid, and the elasticity will make the intermolecular forces take longer to propogate than it would take a simple light beam to reach the end.

Another problem with this would be curvature of the cylinder. If the cylinder were not perfectly straight, rotating it as you suggest would inscribe a huge sphere at the other end of the wire, or if the wire were long enough, it would hit the surface of the earth since the earth is round.

Fiber optic cables really are much more efficient than a pole anyway, since you don't have to worry about the mass of the transmission rotating and the amount of signals you can send per second is much larger than rotations of a pole you could make per second.

plus, it hasnt been done before because it has no practical use yet. fiber optics are much easier, and we have no need for faster than light communications in our world, present day. plus, like vrael said, i dont think it would work.

This isn't really possible...somewhat like Nerdy said, the solid itself isn't affected throughout instantaneously...
Watch a slow motion of a bullet hitting a metal plate. The front end hits the metal, stops, and the back continues to push and compress the front and middle of it.

it has a practical use. In fact this is *one* of the reasons why we really cant go outside our own solar system yet. sure you can send one generation into space searching for a new places and things to explore, but what good is this if you can't relay the information back? It may take generations to get somewhere but if it takes the same time to send information back from that somewhere it pretty much doubles the time depending on your means of communication. With faster than light communication we would be 1 step closer to becoming space explorers which would expand our knowledge 100 fold or better.

It could be done with a laser, sure, regularly pulsing by spinning. On a flat plane.

Why would it need to be twisted? Why not just moved backwards and forwards?

I can imagine that warping would still happen, but not as much.

Moving the pole backwards and forwards still relies on the propogation of intermolecular forces, which cannot exceed lightspeed. Imagine what happens when you have a slinky on top of a table, and you jiggle one end. You see a wave crest shoot down to the other end of the slinky, well, that's exactly what happens when you push on the end of a pole, except you don't see the wave because in normal distances it happens too fast for the eye to see, and on too small a scale for the eye to see.

Another problem with this would be the additional lag caused by accelerating the mass of the pole, which ultimately must start from some frame of reference taken to be a "rest" frame and either accelerates or deccelerates enough for the observer on the other end to measure the change, whereas light travels at light speed as soon as you turn on the flashlight or lazer or whatever light mechanism you happen to be using.

FYI, this "long metal rod/string" idea is limited by atoms bumping into each other, and would thus be limited to the speed of sound.

rockz is right. It is a wave that propegates across the rod. It will go at the speed of sound. Quantum entanglement is useless for communication. You measure the first atom. If it is in a certain state, you can tell the other is, too. But how will you tell the other side when to measure the atom? If either side measures at any time, it will ruin the entire set-up. What are you talking about with a laser? That would go at the speed of light. Another practical application is in computers. Some of the CPUs can make calculations faster than the speed of light. The calculation is so fast that you have to wait for the data to move inside the computer.

yes, but as of now it has no practical use, since we aren't looking to put people into that deep of space yet...