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In his answer to this question, TildalWave made this remark:

I think that first, we have to properly appreciate the size of the Sombrero Galaxy. It is roughly 50,000 light years (15 kilo parsecs) in diameter. That might be only half of the diameter of our own Milky Way galaxy, but still makes each and every pixel on the photograph you're attaching in your question stretch more than 100 light years in distance.

Here's the photograph:

sombrero galaxy

Since it almost feels like I can see individual 'pieces' of dust in the lane, it would follow that the particles must be very far apart. Just how far apart are they? Are they grouped in clumps, or relatively evenly space?

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I think your assumption is incorrect. You can't see individual pieces. You are seeing the variation in particle density, and looking at the photo - there does look to be clumping, and there are bound to be tidal effects. –  Rory Alsop Sep 30 '13 at 19:56
    
Note the 'feels like' - I know it's incorrect, but the dust certainly doesn't look very dense. –  Undo Sep 30 '13 at 19:58

1 Answer 1

Based on 1995A&A...303..673E,

How far apart they are?

No idea. Somebody else might help to provide a density distribution.

Are they grouped in clumps or relatively even spaced?

This is what I really wanted to answer. They are in a concentric ring-like structure around the galaxy. The maximum optical depth is 0.8 with a mean value of 0.3. By the way, optical depth gives you a nice idea of how far apart they might be, not a good density distribution but you can get the physical picture in mind.

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this doesn't answer the question –  Rory Alsop Oct 1 '13 at 12:12

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