The cosmic rays of highest energy are protons that have kinetic energy on the order of 1013 MeV. (a) As measured in the proton's frame, what time interval would a proton of this energy require to travel across a galaxy which has a proper diameter 1.42 x 103 ly? (Assume the kinetic energy of the proton is exactly 1013 MeV.) 1.7e10 X s What is the value of y for this proton? (b) From the point of view of the proton, how many kilometers across is the galaxy? 10e8 X km What is the speed of the proton relative to the speed of light