On Jun 25, 2004, at 12:47 AM, Jinx wrote: >> imagine the rod to be a few light years long, and very rigid > > I've wondered about that too. I'm sure Albert has it covered > Mechanical impulses move at the speed of sound. Which is a bit obvious once you've been told a couple times, since after all sound is just a mechanical impulse... the speed of sounds in "very rigid" solids is quite high, but well below the speed of light....) (so. are there "superconductors" of sound where the speed and "resistance" are dramatically different than normal solids? How about phonic semiconductors? (phononics?)) BillW -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads