46 nanometers less than a light year

On October 15, 1991 a particle detector operated by the University of Utah detected an extremely unusual event: a cosmic ray particle traveling at close to the speed of light.  This was a particle of matter, not a form of lightwave, an energy emission of any kind.  Light always travels at, well, the speed of light.

Matter is a different story.   This particle was matter.  Matter moving exceptionally fast.  So fast that, in the course of one year, it would have traveled only 46 nanometers less than a light year.

Such a phenomenon is called an ultra-high-energy cosmic ray.  “Cosmic ray” is a misnomer – there are actually only cosmic particles streaming at us, at every moment, from every direction, coming from all over the Universe.  This particular thing was a particle which got accelerated to an extraordinarily high velocity somewhere else in the Cosmos, only to pelt through the detector in Utah, enough to stun astrophysicists who dubbed it the “Oh My God Particle”.

According to the Wikipedia article on Ultra-high-energy cosmic rays such events are rare.  Only about 15 have subsequently been observed.