<p>By an estimated order of magnitude there are about $10^{22}$ in our observable universe (<a href="http://en.wikipedia.org/wiki/Observable_universe#Extrapolation_from_number_of_stars" rel="nofollow">hundred billion galaxies with hundred billion stars, each, as a rough estimate</a>), and the <a href="http://en.wikipedia.org/wiki/Age_of_the_universe" rel="nofollow">universe exits since</a> (order of magnitude) $10^{10}$ years. Hence the average formation rate of stars has been about $10^{12}$ per year, meaning more than 10,000 per second, give or take a factor of 100. This calculation ignores stars which don't exist any more, but for an order-of-magnitude estimate numbers should be ok.</p>

<p>Although the star formation rate has been much higher in the younger universe than today. (<a href="http://www.nasa.gov/mission_pages/herschel/news/herschel20130417.html#.U2oKMYF_uqg" rel="nofollow">One of the press releases</a> about star formation in the early universe)</p>

CC BY-SA 3.0
2014-05-07T10:30:32.437Z
2014-05-07T10:30:32.437Z
Gerald
<p>There are many more stars in the universe than the years that the universe has been in existence, so wouldn't this mean that stars were/are forming at an astounding rate?</p>

CC BY-SA 3.0
2014-05-07T08:51:34.797Z
It depends, on where and when. You should constrain a bit your question. Also the very first statement is not clear to me.
Py-ser
CC BY-SA 3.0
2014-05-07T10:26:10.380Z
That depends on your definition of what is an `astounding rate`.
DrCopyPaste
<star><universe><space-time>
How often do stars form?
Michael Blake
# How often do stars form?

(Asked by: username_0 on 2014-05-07)

There are many more stars in the universe than the years that the universe has been in existence, so wouldn't this mean that stars were/are forming at an astounding rate?

**Tags:** star, universe, space-time
> **Comments:**
> **username_1**: It depends, on where and when. You should constrain a bit your question. Also the very first statement is not clear to me.  
> **username_2**: That depends on your definition of what is an `astounding rate`.  

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## 1 answers

### Answer by username_3 on 2014-05-07. Score: 4

By an estimated order of magnitude there are about $10^{22}$ in our observable universe ([hundred billion galaxies with hundred billion stars, each, as a rough estimate](http://en.wikipedia.org/wiki/Observable_universe#Extrapolation_from_number_of_stars)), and the [universe exits since](http://en.wikipedia.org/wiki/Age_of_the_universe) (order of magnitude) $10^{10}$ years. Hence the average formation rate of stars has been about $10^{12}$ per year, meaning more than 10,000 per second, give or take a factor of 100. This calculation ignores stars which don't exist any more, but for an order-of-magnitude estimate numbers should be ok.

Although the star formation rate has been much higher in the younger universe than today. ([One of the press releases](http://www.nasa.gov/mission_pages/herschel/news/herschel20130417.html#.U2oKMYF_uqg) about star formation in the early universe)


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