From the pages of Nature comes the story of the Brazilian physicist who has solved a long-standing paradox about relativistic submarines. Spectators on an anchored ship would see the a passing light-speed submarine shrink in size as it moves parallel to the surface at near-light speed. From their point of view, the resulting density increase would sink the vessel. The submarine crew would see the opposite: water rushing past them would contract and get denser, making the submarine more buoyant and causing it to rise. So…does a relativistic sub sink or swim?
It sinks, says George Matsas of the State University of So Paulo in Brazil. He has used the theory of general relativity to include the effect of the different reference frames on the space-distorting force of gravity. Although the surrounding water does look denser to submariners, they also experience gravity as being stronger, creating a net downward force. Maybe this can be the plot of a SeaQuest reunion show.
Fast subs naturally made me think of fast torpedos like the supersecret Russian Shkval which supposedly “flies” at an astounding 200+ MPH underwater by using a rocket engine to produce a constantly-replenished steam bubble that surrounds the vehicle as it homes in on its target. That target, of course, would be a vulnerable multi-billion dollar U.S. aircraft carrier that is helpless to stop such a incoming banshee. It’s widely believed that the sinking of the Russian submarine Kursk was somehow linked to a test of a Shkval or Shkval varient that went horribly wrong. The Kursk accident doesn’t mean the end of hypervelovity torpedos, tho. The United States may yet be on the receiving end of one or more of these in the opening salvo of a future war…
All the stuff about Shkval is subject to considerable question. This subject has been beaten to death on Usenet sci.military.naval. Shkval is extremely noisy and relatively unguided. It was originally designed as a last resort defense for Russian subs to fire back down the track of an incoming torpedo from a US sub.
As far as Shkval and aircraft carriers, Shvkal will never get near a us aircraft carrier, for the simple reason that most Russian subs don’t leave port. Besides, modern opponents have much more effective weapons like wake-homing under keel torpedos and Exocet type missiles that go Mach 4, not 200 kts.