Nah, most of the random atoms floating around in space are going to be travelling very roughly as fast as the things (stars, planets, etc..) around them -- because anything travelling much faster is likely to eventually bump into something and lose some of its momentum.

There is the occasional weird exception though: https://en.wikipedia.org/wiki/Oh-My-God_particle

> couldn’t protons in any reference frame be going quite fast relative to you?

By the laws of physics, yes. But most of the stuff in our universe, and definitely in our galaxy, tends to move roughly at the same speed.

See https://en.wikipedia.org/wiki/Comoving_and_proper_distances#...

not so much protons (which would be a problem, but could at least notionally be deflected), but atoms.

An hydrogen atom and a proton are roughtly the same thing, right?

no a proton is a hydrogen nucleus (or at least can be seen as one) and has a charge. travelling near lightspeed you would have to worry most about uncharged atoms/molecules (because of their mass) and neutrons, neither of which can be deflected.

A proton is a hydrogen ion and isotope.