I understand the origin of cosmic rays is well studied but the results are inconclusive. I'll point out a link in the page above to another Nature article
"Cosmic-ray theory unravels". Here are a couple quotes
"We're not close to writing the final chapter."
"Low-energy cosmic rays, made mostly of protons, strike Earth continually. They originate within the Milky Way but are seen coming from all directions in the sky because magnetic fields in the Galaxy bend their paths and obscure their original sources. Higher-energy cosmic rays from outside the Galaxy are much less frequent, but are potentially more valuable as astronomical tracers because they barrel into the Galaxy on straighter paths...gleaning clues about these cosmic rays is difficult because of their rarity; on average, fewer than one particle per century strikes a square kilometre of ground. "
Now I am not saying all this shit to disrespect the scientists dedicating their lives to studying the mysteries of the universe. Honestly I have a lot of respect for them, even though I may not sound like it sometimes. But there is a white elephant that I would like to hear scientists talking about more often:
- much of our our historical record is based solely on carbon dating (not all of it, but a lot)
- carbon dating is based on cosmic rays
- we do not know what causes cosmic rays
- therefore we have no solid evidence that in prior millennia cosmic rays reached the earth with the same frequency that they do today (in fact, there is much evidence to the contrary)
- therefore there may be potentially gigantic errors in our historical record.