Okay Brett, seems you're educated so I'll try to keep up as far as I can. I'm an armchair type and I really only have mid-high school mathematics. I've read about Chaos, Einstein's theories and even pretended to understand some Hawking, but that's as far as I go.
To clarify the photons hitting the eye idea, which is my guess...let's assume photons are behaving like particles and not waves for my purposes...I'll bring up the 'Double Slit' experiment later.
Imagine your eye is 93 million miles from a star...our sun makes a great example (;(). The sun is putting out countless numbers of photons every second and in order to perceive the sun, our eyes react with a certain number of them...a pretty high order of magnitude. Some are filtered out but we 'see' the sun. Now imagine your eye is 93 BILLION miles from the sun. Seems to me that the number of photons that actually reach the retina is diminished given that the photons radiate from the sun in all directions. Another illustration would be that you get wetter standing closer to the sprinkler.
Galaxy centre question...dark clouds.
Are you referring to dark clouds of ordinary matter or 'dark' matter? Either way, I understand. Although it would seem like the pea sized Mercury blocking out the sun. I suppose if I was closer to Mercury, that could happen.
String
Currently watching the DVD of the 'Elegant Universe' but I don't have much time lately...I can't watch it and concentrate on large enough chunks with demanding two and a half year old and a three week old both needing attention.
Fractal dimension
Not sure I'm following your expression correctly. When you ask 'Could the universe have a dimension of 6.3?' I'm not sure if you're asking if it could have 6.3 dimensions...which implies 0.3 of a dimension as well as the other 6 which I find difficult to visualise.
How modern is your personal understanding of physics? Mine can be a little 'Carl Sagan' at times, so please bear with me.
Peace.
