The Oh-My-God Particle.

[swestrup]

According to Wikipedia, in 1991 scientists detected a proton that had somehow been accellerated to the point that it had the energy of a baseball moving at 27MPH. Since then there have been another 15 sightings of these hard-to-explain particles.

Comments

[mricon.livejournal.com]

small correction: not 27mph, but 27 m/s, which is about 60mph.

I've heard of these before from grad-students when I was working at the department of Physics at Duke, but didn't know the details, so it's fun to read some more about it.