It's not that the atmosphere does not protect us. Just not 100%, which shows just how much energy (a tiny fraction of) these particles have. So yes, you get a f

It's not that the atmosphere does not protect us. Just not 100%, which shows just how much energy (a tiny fraction of) these particles have. So yes, you get a few atoms in your body blown off by a cosmic ray once every few months or so. In space you can expect that to increase to several times per second (as compared to solar rays, which of course constantly hit). This was a statement meant to illustrate that so far we haven't really found an upper bound for the energy levels of these particles. Give a particle enough energy and it'll fly right through the planet. http://en.wikipedia.org/wiki/Cosmic_ray http://en.wikipedia.org/wiki/Cosmic_ray The interesting thing is that we don't actually know where most of these rays come from (about 1 in 100 million comes from a supernova/black hole/other known powerful event). So something is pretty much everywhere in space, shoots out particles like a particle accelerator, except much more powerful than the ones we can build. Yet whatever is doing this manages to avoid detection by any other means.