I know this sounds like a strange question but I'm trying to make a thesis-paper/informational on the physical states of matter (Yes ofcourse I know liquid, solid, gas, and plasma) but I once read in a physical science book (and even saw an illustration) of certain particles that come from space that constantly pass *through* US and the EARTH. They don't apply physically to us and (most likely) we can't illuminate them in our visible spectrum. I also know of another state of matter that is reached at "absolute zero" but that is still a physical state. Please help me if you can to find out which particle (if any) can pass through us and give examples (and preferably a link so I can have a reference for my paper besides: someone told me). Thnx.