Relative sizes / distances between stars and galaxies

Hi Chaps,

I came across a reference a while back (I forget where) which said that the
average distances between stars is much greater in proportion to their size than
is the distance between galaxies in proportion to _their_ size. I'm interested
to find out what are the actual average distances between stars, and similarly
for galaxies, and also the mean size of stars and the mean size of galaxies ?

Thanks,

--
Boo

In message , Boo
writes
Hi Chaps,

I came across a reference a while back (I forget where) which said that
the average distances between stars is much greater in proportion to
their size than is the distance between galaxies in proportion to
_their_ size. I'm interested to find out what are the actual average
distances between stars, and similarly for galaxies, and also the
mean size of stars and the mean size of galaxies ?

Hint. You can find this for yourself with minimum effort by using the
Web or another marvellous invention - a book.

As this is my first post of 2007, Happy New Year to all!

Hint. You can find this for yourself with minimum effort by using the
Web or another marvellous invention - a book.

Or indeed, usenet.

--
Boo

Happy New Year from Columbia, SC.

Now let's see.

This is only an approximation:

first for stars in our solar system, let's start with the Sun and Alpha
Centauri (nearest star system)


Distance from Sun to Alpha Centauri --- about 4.35 light-years = 41.2 x
10^12 km

Diameter of the Sun --- about 1.4 x 10^6 km

So let's take a ration of distance to Alpha Centauri with respect to dia.
Sun --- 41.2 x 10^12 km/1.4 x 10^6 km = 29,000,000

So there's enough room between our Sun and the next star system for 29
million sun's lined side by side.


Next let's look at the Milky Way galaxy and the Large Magellanic Cloud
(though we know of 1 maybe 2 galaxies presently being consumed by the Milky
Way - let's go with LMC since it is still free ... for now...from galactic
cannibalism).

Distance to LMC is about 180,000 light years

Diameter of the Milky Way galaxy is about 100,000 light years

so let's take a ration of dist. to LMC with respect to the diameter of Milky
Way and we get 180,000/100,000 = 1.8

So there is not even enough room between these neighboring galaxies for 2
Milky Ways!!

Just an approximation -

--
Thanks,
Jeffrey



"Boo" wrote in message
.. .
Hi Chaps,

I came across a reference a while back (I forget where) which said that
the average distances between stars is much greater in proportion to their
size than is the distance between galaxies in proportion to _their_ size.
I'm interested to find out what are the actual average distances between
stars, and similarly for galaxies, and also the mean size of stars and
the mean size of galaxies ?

Thanks,

--
Boo

Distance from Sun to Alpha Centauri --- about 4.35 light-years = 41.2 x
10^12 km

Diameter of the Sun --- about 1.4 x 10^6 km

So let's take a ration of distance to Alpha Centauri with respect to dia.
Sun --- 41.2 x 10^12 km/1.4 x 10^6 km = 29,000,000

So there's enough room between our Sun and the next star system for 29
million sun's lined side by side.

....snip...

Distance to LMC is about 180,000 light years

Diameter of the Milky Way galaxy is about 100,000 light years

so let's take a ration of dist. to LMC with respect to the diameter of Milky
Way and we get 180,000/100,000 = 1.8

So there is not even enough room between these neighboring galaxies for 2
Milky Ways!!

Thanks for that, that was the type of info I was looking fro, but can anyone say
what the average size of a galaxy is and the average distance between them ?

Thanks again,

--
Boo

They come in such a wide range of sizes from dwarf elliptical (perhaps the
smallest) to giant elliptical (perhaps the largest). Notice both extremes
were elliptical galaxies. There are other types of course: spirals, barred
spirals, and irregulars. Then there are active nuclei galaxies which appear
to be the by-product of galactic collisions of types mentioned above. But I
imagine someone could come up with a rough estimate on the average size -
which may be around 80,000 ly but the error bars on such a value would be
too large to give such a number credence.

Then there is the problem of average galactic separations - which is not
easily stated either since galaxies tend to come in groups (galactic
clusters) with individual galaxies scattered nearly randomly within such
clusters. Then these clusters seem to group in clusters (galactic super
clusters) and perhaps so on and so on. Then end result it that there is not
a known overall average distance when taking into account all known
galaxies.

--
Thanks,
Jeffrey

Physics and Astronomy
Columbia, South Carolina
http://midlandstech.com/jlh



"Boo" wrote in message
.. .
Distance from Sun to Alpha Centauri --- about 4.35 light-years = 41.2 x
10^12 km

Diameter of the Sun --- about 1.4 x 10^6 km

So let's take a ration of distance to Alpha Centauri with respect to dia.
Sun --- 41.2 x 10^12 km/1.4 x 10^6 km = 29,000,000

So there's enough room between our Sun and the next star system for 29
million sun's lined side by side.

...snip...

Distance to LMC is about 180,000 light years

Diameter of the Milky Way galaxy is about 100,000 light years

so let's take a ration of dist. to LMC with respect to the diameter of
Milky Way and we get 180,000/100,000 = 1.8

So there is not even enough room between these neighboring galaxies for 2
Milky Ways!!

Thanks for that, that was the type of info I was looking fro, but can
anyone say what the average size of a galaxy is and the average distance
between them ?

Thanks again,

--
Boo