>>13206359>In this case though--what the hell do the 'strings' or 'bridges' represent? There is literally hidden matter AWAY from galaxies and between them?Not just dark matter, normal matter too. These structures are part of the cosmic web, galaxies form in the dense nodes of the web but the filaments remain. The filaments are dominated by dark matter but they also contain normal matter in the form of hot ionised plasma. The volume in between galaxies isn't empty, there is sparse matter in the intergalactic medium. In the current universe the normal matter in these filaments is also very difficult to detect, because it's hot and sparse it emits very little light.
This is an image from a galaxy formation simulation. It shows scales much larger than galaxies. On large scales you see the cosmic web, the colours is the temperature of the gas. The zoom panels show you a spiral galaxy, which lives in part of the web. Galaxy clusters live in the dense centres of the web, surrounded by even hotter gas.
