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Happy 50th Cern!
Anonymous Coward writes "The facility that has earned three scientists Nobel prizes, provided the impetus for Berners-Lee's hypertext program (aka the WWW), oh and has also helped answer some fundamental questions regarding the universe has turned fifty today! And with the LHC in development, here's hoping for another 50!"
Can humanity possibly put a price on knoledge? Is there a limit to the ammount of money we should spend to learn - to further our understanding of the world around us?
/mod me off topic if you want
In nature, there are neither rewards or punishments, there are only consequences.
that's a four-momentum, man.
(I did make it small p unlike capital P later on, didn't I?)
Ever heard about Lorentz vectors? (E, px, py, pz) with "funny" (1, -1, -1, -1) metric (flat space diagonal) meaning when you multiply them, or square in our case, it expands to E^2 - px^2 - py^2 - pz^2. The magnitude of four-vector is called "interval". Four-momenta of real massive particles have interval > 0 ("time-like"), photons have inteval=0 ("light-like"), events in time-space that cannot possibly be cause-effect related are separated by interval less then 0 ("space-like").
Special Relativity postulated that interval is the same in all possible coordinate systems(4D of course), and everything else is derived from it. That's all there is to Special Relativity.