May/June Sky and Telescope had an article on a cosmic superparticle that travels nearly the speed of light. If it originated in NGC 5128 twelve million light years away, it only experienced twenty minutes in flight due to relativistic time dilation. Can someone explain the physics, equations that are used to come to this conclusion. I presume that time is slowed at the speed of light, and that twelve million light years distance only seems like twenty minutes travel? Also, if scientists could produce high energy particles near this speed, could they "ping" them at distant objects( a bit like radar ) to accurately measure distance?
