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Comment by ricardobeat | Hacker News Reader

What if the string is completely non-elastic?

At those sizes there is no such thing as "completely non-elastic" (aka "rigid").

This. Diamond is one of the stiffest materials in existence. It has a sound speed of 12 000 m/s. Lightspeed is 300 000 000 m/s.

At any size, there is no such thing as "completely non-elastic", but at those sizes, pretending that some things are completely non-elastic is no longer a tolerable approximation.

How about observing a quantum-entangled particle 1AU away from its partner? Can the speed of information surpass the speed of light? I'm a physics noob so I wouldn't know about research in the field.

As far as we can tell, the effect of measuring an entangled particle is at least 10000 faster than the speed of light. According to theory, it's instant. You can't use it to transfer any information, though.

I assume that complete non-elasticity of something would violate the (presumed) light speed limit on causality.

What if the string isn't actually made of matter but is made up of some hypothetical substance that doesn't follow any laws of physics?

Same question.

If you can persuade people that you can make that hypothetical substance, there are a few pissed off investors around at the moment who will throw money at you.

> What if the string isn't actually made of matter but is made up of some hypothetical substance that doesn't follow any laws of physics?

If it doesn't follow any laws of physics, then there is no predictable relationship between any input and its action (since if there was such a predictable relationship, it would be a law of physics that the string was obeying.)

Since it doesn't follow any laws of physics: it actually moves the opposite way than the way you tugged it ;-)

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