<p>Interesting question, but it is quite difficult to provide an accurate estimate for each order of magnitude without a comprehensive survey.</p>
<p>Most galaxies in the universe are likely dim dwarfs that are hard to see and catalog. So it's not easy to give a percentage based on star count since we don't really have perfect numbers either, but I can try to give you a general idea of the distribution.</p>
<p>Our own absolute monster of a galaxy has just over <a href="https://en.wikipedia.org/wiki/Satellite_galaxies_of_the_Milky_Way#:%7E:text=There%20are%2061%20small%20galaxies,orbit%20of%20other%20satellite%20galaxies." rel="nofollow noreferrer">60 confirmed</a> galaxies within 1.4 million light-years, either orbiting us or not. We may be an exception for having so many satellite (or at least nearby) galaxies because the Milky Way's mass is thought to be quite high, even compared to many other major ones - but if we assume this figure is generally uniform throughout major galaxies, without considering independent dwarf galaxies, we can see that they out-populate massive galaxies by <em>at least</em> 60 to 1.</p>
<p>So most galaxies would fall on the lower end of star count and galactic mass. I'd estimate that well over 98% have <span class="math-container">$&lt;10^9$</span>, while the remaining few have <span class="math-container">$&gt;10^{10}$</span>. But as I said, it's hard to come up with an accurate ratio since we don't really know how many compact galaxies exist, simply because they are hard to observe. So take that figure with a grain of salt since it came from some generalizations.</p>

CC BY-SA 4.0
2024-01-10T14:10:26.040Z
2024-01-10T14:27:06.430Z
2024-01-10T14:27:06.430Z
4NT4R3S
<p>First off, I realize how hard this is to even come close to estimating, but I'm trying to get a &quot;general feel&quot; for the distribution of galaxies by star count. I realize everything from rogue stars to super massive galaxies with trillions of stars exist... but I'd really love to see an estimated percentage of galaxies in the observable universe with:</p>
<ul>
<li>&lt;10^5 stars</li>
<li>10^5 - 10^6 stars</li>
<li>10^6 - 10^7 stars</li>
<li>10^7 - 10^8 stars</li>
<li>10^8 - 10^9 stars</li>
<li>10^9 - 10^10 stars</li>
<li>10^10 - 10^11 stars</li>
<li>10^11 - 10^12 stars</li>
<li>10^12 - 10^13 stars... etc.</li>
</ul>
<p>Does anyone know where I could find some estimates on this... Or even on galactic mass</p>

CC BY-SA 4.0
2023-09-23T12:52:32.980Z
Richard Mushotzky has a nice page on the luminosity function of galaxies. https://www.astro.umd.edu/~richard/ASTRO620/LumFunction-pp.pdf
eshaya
CC BY-SA 4.0
2024-01-11T03:57:52.433Z
@eshaya how was this function obtained?  Is it empirical or is it derived from some physical considerations?
ayr
CC BY-SA 4.0
2024-01-11T14:50:57.410Z
The Luminosity Function is derived empirically by measuring the brightness of all galaxies within a certain distance from us.  It requires good distance determination to groups and clusters.
eshaya
<star><galaxy>
Distribution of Galaxy sizes (star count)
Cameron Critchlow
# Distribution of Galaxy sizes (star count)

(Asked by: username_0 on 2023-09-22)

First off, I realize how hard this is to even come close to estimating, but I'm trying to get a "general feel" for the distribution of galaxies by star count. I realize everything from rogue stars to super massive galaxies with trillions of stars exist... but I'd really love to see an estimated percentage of galaxies in the observable universe with:

* <10^5 stars
* 10^5 - 10^6 stars
* 10^6 - 10^7 stars
* 10^7 - 10^8 stars
* 10^8 - 10^9 stars
* 10^9 - 10^10 stars
* 10^10 - 10^11 stars
* 10^11 - 10^12 stars
* 10^12 - 10^13 stars... etc.

Does anyone know where I could find some estimates on this... Or even on galactic mass

**Tags:** star, galaxy
> **Comments:**
> **username_1**: Richard Mushotzky has a nice page on the luminosity function of galaxies. https://www.astro.umd.edu/~richard/ASTRO620/LumFunction-pp.pdf  
> **username_2**: @eshaya how was this function obtained?  Is it empirical or is it derived from some physical considerations?  
> **username_1**: The Luminosity Function is derived empirically by measuring the brightness of all galaxies within a certain distance from us.  It requires good distance determination to groups and clusters.  

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## 1 answers

### Answer by username_3 on 2024-01-10. Score: 2 | Accepted answer

Interesting question, but it is quite difficult to provide an accurate estimate for each order of magnitude without a comprehensive survey.

Most galaxies in the universe are likely dim dwarfs that are hard to see and catalog. So it's not easy to give a percentage based on star count since we don't really have perfect numbers either, but I can try to give you a general idea of the distribution.

Our own absolute monster of a galaxy has just over [60 confirmed](https://en.wikipedia.org/wiki/Satellite_galaxies_of_the_Milky_Way#:%7E:text=There%20are%2061%20small%20galaxies,orbit%20of%20other%20satellite%20galaxies.) galaxies within 1.4 million light-years, either orbiting us or not. We may be an exception for having so many satellite (or at least nearby) galaxies because the Milky Way's mass is thought to be quite high, even compared to many other major ones - but if we assume this figure is generally uniform throughout major galaxies, without considering independent dwarf galaxies, we can see that they out-populate massive galaxies by *at least* 60 to 1.

So most galaxies would fall on the lower end of star count and galactic mass. I'd estimate that well over 98% have $<10^9$, while the remaining few have $>10^{10}$. But as I said, it's hard to come up with an accurate ratio since we don't really know how many compact galaxies exist, simply because they are hard to observe. So take that figure with a grain of salt since it came from some generalizations.


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