Interesting to see this post as since I was here last most of my time has been applied to considering what is in the remotest part of space and what one could expect to find in the supreme realm of nothing.
The fact is there will be heaps..consider the electromagnetic radiation passing by at any point.... seemingly limitless on my estimation...
when one thinks what a grain of sand held at arms lenght will hide.. (that was the approximate field of view for the Hubble Deep field)... I translate that to mean that wherever we look one grain of sand hides some 2000 galaxies as established and probably many more than that... and given they (Hubble team) picked the darkest spot etc for the deep field exposures one could reasonably assume that our grain of sand will hide that many galaxies wherever we hold our arm... now if we go to the regions of our universxe where we can examine nothing..the voids... then I expect that there our arm length holding the grain of sand will also hide many galaxies..in any direction the galaxies and the energy they send to where we observe even in the middle of the largest void is mind boggling...my point is simply that in the middle of nothing the energy passing thru from everywhere is for practical purposes near infinite... we may find only one hydrogen atom every 4 light years or so (whatever) but the energy will be jam packed at any and every point...in fact when you think it thru there is so much passing by it is wonderous that it all manages to fit
As to a hydrongen atom travelling at speed I often wonder if the hydrogen in a hydrogen bomb is there not for any energy release via the conversion to helium thing as we all believe but that the hydrogen forms merely a schrapnel jacket.much like placing bolts and nails in a fertilizer bomb...being so small those atoms must get up some speed and imagine just one hitting anything at near c... E=MC^2 would suggest that I feel... so how fast do the hydrogen atoms accelerate to??? and what if just one hit a gum tree..would it do any damage??
alex
