As an exercise the time distortion factor for a 3 million light year trip in 30 seconds is roughly ~ 1,000,000 x 3,000,000 = 3 trillion! Extreme energy of particles is measured in giga-electron volts, GeV - a proton masses ~ 1 GeV. An iron nucleus masses ~ 55 GeV, hence this cosmic ray packs a whopping ~ 165 trillion GeV or 165,000 peta-electron volts. That's 26 kiloJoules. Fortunately if it came our way it would promptly smash into an oxygen nucleus in the stratosphere and spread a shower of muonic debris over a few kilometres of Earth's surface.

The most energetic cosmic rays typically pack a mere 100 peta-eV, so Gary has taken a bit of license with this example.

Adam