Re: Relationship between magnitude and distance

On Thu, 26 May 2005 23:28:46 GMT, "David Nakamoto"
<res07oeg@xxxxxxxxxxx> wrote:

>My intuition and my reasoning minds cannot agree with this. Imagine the galaxy
>as a series of sheets, the sheets perpendicular to the plane of the galaxy and
>to our line of sight. For simplification purposes imagine each *** contains
>the same density of stars distributed randomly, and that all of them are
>represented by dots of more or less the same size. Certainly this is close to
>how ellipticals are organized, and the arms of spirals only means that some
>sheets have less stars than others.
>
>Now imagine looking at the galaxy edge-on. As you look through the various
>sheets, it becomes more and more probable that a star will block your view of
>what is behind it. So as you look deeper and deeper into the galaxy edge-on,
>pretty soon you can't see anything deeper because all the stars on those sheets
>cover the entire view.

I think maybe this has something to do with the size of a stellar image
versus the actual angle subtended. The odds of one star blocking another
are very small in a galactic core. I did this calculation years ago for
a dense globular, and the results were just that. If you consider a
random vector passing through a globular, the odds of it intersecting
any stars at all is very small- a few thousandths of a percent IIRC.

However, a stellar image usually subtends a much larger angle than the
star itself. That's why most images of globulars appear solid in the
center. But I've seen AO images of galactic cores and globulars where
you clearly see space between all the stars.

What this means is that in an image, it appears that stars overlap. But
actually they do not, so you don't get a reduction in total energy from
this effect.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
.

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