I'm no cosmotolicist, so forgive me if I'm completely off the mark here.
A few years back, I read that there is not enough matter in the universe to account for the gravitational forces at play, keeping the stars clumped together as galaxies. Then the other day, I saw a show that I'd seen before about the structure of the solar system. It said that we cannot directly observe the Oort cloud, but we can infer it's existence by the stuff we do see, mainly comets. So there's pretty solid evidence that it exists.
That got me thinking as it did before, that if our local run-of-the-mill star has an Oort cloud, this ginormous cloud of ice n shit, then every other star must have one too. Apparently, this thing is so gigantically huge that it reaches half way to Alpha Centauri, where I suppose, it meets that star's Oort cloud. Just imagine how large this cloud would be for a supergiant or a massive black hole. If that is correct then these clouds must fill the whole galaxy pretty much, I'm not good at maths but that's a lot of mass, right?
So was all this extra mass taken into account?
This might sound silly to physics professionals, but why doesn't that much debris floating around affect observations from here on earth, even just to dim intensity of a star's light, so as to give an incorrect estimate of distance or size?