relativity

  1. A

    Special Relativity Q's

    Our galaxy is about 10^5 light years in diameter. (a) How fast would a spaceship have to travel in order to cross the galaxy in 300 years as measured from within the spaceship? (b) How much time would elapse on Earth during the transversal? For this question i seem to have got that the velocity...
  2. E

    special relativity

    Please tell me if we could consider L=gL(0) m=gm(0) g Lorentz factor as experimental facts?