[freebeard]

I'd been silent on this because I didn't want to stray off topic, but you've opened the door. https://en.wikipedia.org/wiki/Intergalactic_dust

Stars attract our interest because they twinkle and beckon to us. The intergalactic medium is filled with filaments of dust that pour into the galaxies and drive new star formation.



An Ancient Solar System...: Dust, the ultimate cosmic mystery (maybe)...

Why? Because space dust is old, strange, stuff: It was the first solid matter in the universe. It was the building material for all the planets, dwarf planets, moons and asteroids. Thinly spread dust fills space: Some is ‘just’ from asteroids and comets, and some actually grew in the outer layers of ancient stars, or was forged in a supernova. Even garden variety space dust contains rock, water, gases like oxygen, and precursor molecules to life - basically all the stuff that goes into making a world like Earth.

In fact planets are small fry for space dust. Paradoxically, space dust thinks big. It forms massive structures, trillions of kilometres aross, as it gets blown about by stellar winds and pulled by gravity, like nebula.....

These huge structures give birth to stars, planets, and solar systems – and they’re everywhere! Look up at the milky way. See those dark patches in it? Clouds of space dust waiting to form planets.

The real 'dark matter'.