#### marcus

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Chandrasekhar discovered a formula for the largest mass which can support itself against gravitational collapse by the pressure of its electrons.

this formula has a term (Z/A)

^{2}

how to understand it? well for a given atom Z is the number of electrons! and A is the atomic weight. So Z/A gives a good idea of

how electron-rich it is and how well it will resist collapse. In effect it is an "electrons per weight" number, giving a notion of "pressure per weight" as well.

That's all I have to say about it for now. I tried to understand the formula better today. If anyone has some insight or wants to try to explain it go ahead. Its interesting. The formula is:

0.20 (Z/A)

^{2}(hc/Gm

_{prot}

^{2})

^{3/2}

which is a pure number expressing the mass as a multiple of the proton mass m

_{prot}

In other words, if you want a complete expression for the mass you multiply the number times m

_{prot}and get

0.20 (Z/A)

^{2}(hc/Gm

_{prot}

^{2})

^{3/2}m

_{prot}

That's verbatim from Frank Shu, I use a version rewritten using hbar in place of h.