the research workers at haverah park find no evidence of an upper limit to cosmic ray energies. a proton must have an energy of how many times its rest energy for the diameter of our galaxy to appear to it lorentz- contracted to the diameter of the proton ( about 1 femtometer, which is equal to 10-15 meters)? how many metric tons of mass would have to be converted to energy with 100-percent efficiency in order to give a proton this energy? one metric ton equals 1000 kilograms.