"Astronomers believe they may have identified the source of galactic cosmic rays, the highest-energy particles in the Universe."
"The researchers came to their conclusions after studying several elliptical-shaped galaxies sited in the sky close to the handle of The Plough (Big Dipper)."

I wonder if this sky location was blocked whether you would get a significant reduction in GCR. For instance at the Lunar south pole would the Big Dipper be in the sky at any time?
Also wonder whether we can "read" the history of our Universe by any the effect these high energy particle have on the rocks- if there is a localized and relatively concentrated exposure over say thousands of years. In other words do these really high energy particles leave a distinctive signature in rock which could be read millions or billions of years later?