On 6june19, Newsweek et al., reported on a Science just-published article on previously unknown/unseen galactic cluster radio ridge, also related to magnetic fields, and cross-referred to as "filaments".
All I'm asking youse here is: (best guess, etc., more than ok) what is the nature and composition of these filaments? All I have gathered from wikipedia that these appear to be some sort of material observed and inferred as "lines" gravitationally or otherwise "connecting" galactic clusters (what's the "otherwise" sub-question?). I think I get that common conceptions implied in the use of the words like "lines" can only be loosely applied when trying to understand what goes on, on a scale of billions of light-years, that we can see only thru varying types of scopes and our present senses. So is that what's going on - using a word like "filament" when our ability to conceive and describe what's happening cosmologically, is stretched almost beyond our limits? We simply don't have a better way to say it as yet? Thank you.