Answer: The cosmic rays of highest energy are protons that
Chapter 39, Problem 77(choose chapter or problem)
The cosmic rays of highest energy are protons that have kinetic energy on the order of 1013 MeV. (a) As measured in the protons frame, what time interval would a proton of this energy require to travel across the Milky Way galaxy, which has a proper diameter , 105 ly? (b) From the point of view of the proton, how many kilometers across is the galaxy?
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer