Hit Detection

Imagine the energy of a baseball thrown by a Major-League pitcher.

Imagine getting hit by one.

Now imagine that energy concentrated in a particle that is 10 trillion times smaller than a baseball, moving at nearly the speed of light. Imagine getting hit by one.
Imagine detecting one.

No one knows what creates these ultra-high energy cosmic rays; no one knows where they come from. But, there are some possibilities:

1. An ultra-massive star, thousands of times bigger than our sun.

Such a star can destroy itself in seconds, ripping itself to shreds in a frenzy of superheated annihilation. In the fury of this solar suicide, there may be enough power to create ultra-high energy cosmic rays.



2. A black hole.

At the center of our galaxy--at the center of most galaxies--lies a supermassive black hole: once a star, its gravity was so powerful that the body of the star collapsed in on itself, folding space into an infinitely small point, and so the star vanishes to nothing--but its gravity well remains. When anything falls into the black hole, the infalling object is ripped apart by the incalculable tidal forces. Energy, energy, and more energy pours out of the place where the particles are destroyed; some of this energy may become cosmic rays.



3. Space is vast. The distances between galaxies is vast. And yet, galaxies can, and do collide. And when they do… Galaxies contain a hundred billion stars; they are a hundred thousand light-years side-to-side. When they collide…

When an ultra-high energy cosmic ray (UHECR) is created, it can go in an direction. Any at all. Somehow, occasionally, one heads our direction. More correctly, it heads for the place we will be, eight billion years later.

- Kevin Wheelock