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Regarding star formation, I got curious about how much volume of space in the interstellar medium is actually required to form a star, and to determine that size based on something relatable conceptually. This has no doubt already been done ages ago, and if so please just pass the link on so I can check it out.

Nonetheless, for fun I’ve laid out what I think is a logical sequence and mathematical progression below based on what I hope is reliable information (as reliable as possible at least) that is generally accepted in the science community. So, for those with the expertise and are willing, would appreciate checking to see if my conclusion on the required volume of space to form a star is in the ballpark, though I could have easily messed things up anywhere along the progression. Thanks! I’ve tried to ere on the conservative side each step. Here it is:

**1.**"The density of the interstellar medium ranges from as high as 10 to the power of 6 atoms per cm3 in a molecular cloud”

https://www.quora.com/How-many-atoms-are-contained-in-1-liter-of-interstellar-space

So, though it seems the norm is much much less, I took 1,000,000 atoms per cubic cm as a baseline density for a molecular cloud that’s going to gravitationally collapse to form a star.

**2.**Next, how many atoms are in a star? It has been estimated that there are ~9.1 x 10^56 atoms in the sun (I’m using 9 x 10^56 for simplicity).

https://www.quora.com/How-many-atoms-fit-in-the-sun

Now, that’s the number of today’s atoms. Seems the number would have been significantly higher when the sun was initially formed, but will go with that estimate.

9e56 / 1,000,000 = 9e50

So, based on 1,000,000 atoms per cubic cm, using the number of atoms estimated to compose the sun, it would take 9e50 cubic cm of volume in space to form one star roughly the mass of our sun.

**3.**There are 1,000,000,000,000,000 cubic cm in a cubic kilometer, so 9e50 divided by that number is a volume of 9e35 cubic kilometers of interstellar space required to form a star the mass of our sun.

**4.**The volume of the sun in cubic kilometers is estimated to be 1.4e18 (https://brainly.com/question/72396). So, an estimate of how many suns it would take to fill the interstellar space volume required to form a star is: 9e35 / 1.4e18 = 642857142857142857.

So it would roughly take the volume in space of 642857142857142857 suns to create one star.

**5.**"We can fit

**278.8 billion Suns**in the Solar System

**in a 3D plane**.”

https://www.quora.com/How-many-suns-would-theoretically-fill-up-our-solar-system

642857142857142857 / 279,000,000,000 = 2304147

So, based on this (perhaps highly suspect) math, it would take the volume of over 2 million of our solar systems to form one star.

Now, sun’s aren’t square, so step 4 isn’t completely accurate, so I’ll shave 33% off the total to account for this. 2304147 - 33% = 1,543,778

Again, please check my logic and math and let me know what’s what, but according to the above, the amount of interstellar space (at its densest) that it would take to form one star is an estimated 1.5 MILLION of our solar systems.