"To all intents, cosmic rays arrive evenly from all directions in the sky, but this does not necessarily mean their sources are evenly spread around us. More li

"To all intents, cosmic rays arrive evenly from all directions in the sky, but this does not necessarily mean their sources are evenly spread around us. More likely, they are constantly deflected and scattered by magnetic fields in the galaxy, until any trace of their original motion is lost."[0] A crude hypothesis would be that there's some sort of magnetic field that is directing them from a single location. Since we've never been this far before, its a pretty huge guess... [0]: http://www-spof.gsfc.nasa.gov/Education/wcosray.html http://www-spof.gsfc.nasa.gov/Education/wcosray.html