Faster Than Light Info

[johndoh]

Hi, Faster than light travel of physical objects seems problematical. There is evidence particles can show simultaneous interactions when seprated by a distance. Ie faster than light transmission of information. What about information transmitted via physical bodies with very large dimensions ?. Eg a very long rigid rod pushed at one end simultaneously moves at the other. Could widely separated observers use this to communicate instantaneously (faster than light) over very long distances ?

 

[billslugg]

No, No and No.<br />I am not well versed in this, and I had the same reaction you did. In each case, upon closer examination, the experts said that each case was illusionary. They discussed entanglement, phase velocity vs group velocity and supraluminality. Bottom line is that no mass can reach c and no info can exceed c. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[johndoh]

Thanks Billslugg, My Newtonian biased intuition agrees with you about faster than c physical travel and paired particles. However, the very same intuition develops thought experiments (for instance) involving a non-stretchy cable a light minute long. Pull it and the far end moves simultaneously. A photon would take a minute to travel the same distance. Actually, with modern time measuring equipment, you could do this experiment with much, much shorter cables or rods or whatever.

 

[mako71]

<blockquote><font class="small">In reply to:</font><hr /><p><br />johndoh: Pull it [non-stretchy cable] and the far end moves simultaneously.<br /><p><hr /></p></p></blockquote><br /><br />The problem is to find such cable. All current known materials stretch, and the force is relayed to the other end in the speeds slower than light. <div class="Discussion_UserSignature"> <p> </p><p>________________ </p><p>reaaliaika.net </p> </div>

 

[alokmohan]

The story of tachyons and George Sudarshan.

 

[dragon04]

<font color="yellow">involving a non-stretchy cable a light minute long. Pull it and the far end moves simultaneously.</font><br /><br />While that's correct, the person at the far end is only getting certain information. He knows that the cable was pulled, how far it was pulled, and how much force was exerted to pull it.<br /><br />However, he doesn't know <b>why</b> it was pulled, or what the puller had for breakfast, etc...<br /><br />It's tempting to think that a "hose" full of water "transmits" instantaneously.<br /><br />However, if the ultimate aim of that hose is to deliver 100 degree water (or data through a cable) that 100 degree water has to travel the distance of the hose at a certain velocity (pressure) to deliver the message.<br /><br />The only thing we know "immediately" is that the water was turned on and that <b>something</b> is coming our way.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[johndoh]

You are basically correct Dragon04. But take the thought experiment a bit further. Through trial, error and repetition sentient entities at either end of the very long cable, rod or hose could develop a code, particularly if they had knowledge of mathematics. The principles of maths are supposed to be universal. Anyway what's to stop someone taking a code at subluminal speeds to the far end then communicating instantaneously once there. The thing that interests me about all this is that it all depends on Newtonian physics and things you can hold and see. Also, an experiment to test this could be done using quite short dimensions and precision time measuring equipment.

 

[dragon04]

<font color="yellow">Through trial, error and repetition sentient entities at either end of the very long cable, rod or hose could develop a code, particularly if they had knowledge of mathematics</font><br /><br />I can think of two immediate problems. First would be the the creation of a "rigid structure" at any distance.<br /><br />Secondly, even if one were able to build a perfectly rigid thing like a carbon nanotube filament, the mass of the thing would require a rather prodigious force to move it. The term "irresistable force and immovable object" comes to mind if you take my meaning.<br /><br />I think it would be the analog to moving even a tiny mass at significant percentages of c.<br /><br />I don't believe that the answer lies in either the Newtonian or Einstinian Universe.<br /><br />I rather believe that the key to any superluminal travel or data transmission is the result of bypassing intervening distances as opposed to trying to cross them.<br /><br />stevehw33 had posted a thread about quantum tunnelling and simultaneous data transmission.<br /><br />Newtonian physics works great when dealing with everyday masses and velocities; we don't have to use Einstein's equations to resolve the velocity of our car down to 12 decimal places.<br /><br />However, when we start talking about even the masses and velocities in planetary motion and such, Newton just won't do.<br /><br /><font color="yellow">The principles of maths are supposed to be universal.</font><br /><br />I'd have to agree. If SETI were to detect a repeating 5 or 6 digit fibonacci sequence for example, any natural cause could be easily ruled out.<br /><br />I have no problem with the argument that such simple maths would be universally understood. I just see no way to "instantly" convey them in 4 dimesnsional space-time considering the amounts of energy required.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>