Precision of the Gravitational Constant I went to a theological talk where the speaker, while answering a question on intelligent design, claimed that, if $G$ was different by one part in $10^{120}$,then the universe would either collapse or fall apart. I want to dispute this if I have a chance later.
But does anyone know where this belief may have come from?
He also claimed that there are many other cosmic magic numbers. Numbers that need to be an exact value for the universe to exist. I can neither find anything about magic numbers nor can i think of anything that needs to be precise for the universe to exist. 
Has anyone heard this term or a similar idea?
 A: There are $20$ numbers which are of maximum importance in physics.
Well, $20$ is probably not going to do it these days (maybe you were reading something written before the neutrino oscillation discovery of the late $1990$'s). Before the Super Kamiokande experiments in the $1990$'s, we all thought that neutrinos were massless and didn't mix with each other, and that reduced the number of parameters.
Here goes a tabulation of the parameters: 


*

*masses of electron, muon, and tau leptons (3)

*masses of six quarks: up, down, strange, charm, top, bottom (6)

*Mixing matrix of the down-type quarks, which is parameterized by
four independent angles. To find out more, look up "CKM Matrix" or
"Cabibbo-Kobayashi-Maskawa Mixing Matrix" (4)

*The strong coupling constant $\alpha_s$ (1)

*The fine structure constant $\alpha_{em}$ (1)

*The Fermi constant $G_F$ (governs weak decay rates) (1)

*The Z boson mass $M_Z$ (1)

*The Higgs boson mass (1) (the W mass can be calculated from the other parameters and the theory)

*Gravity has a strength parameterized by $G_N$, Newton's gravitational
constant (1).


That's $19$. Two constants, the speed of light and Planck's constant, define our units of length and time and energy. 
That gets me up to $21$. The neutrino masses are another $3$, and they have a mixing matrix just like the down-type quarks for another four parameters, for a total of $28$. 
These are the constants of the Standard Model, which is incomplete. The Standard Model fails to explain dark matter and dark energy. Dark energy may be parameterizable with just one more constant (Einstein's famous "cosmological constant") or there may be a much richer set of things to understand about it. 
Dark matter is also a mystery. My favorite candidate for what it is is supersymmetric partners of ordinary matter. But then all the supersymmetric partners have masses and mixings and lots of numbers to describe them, introducing (at one count I can dig up in the Particle Data Group's review) of 105 new parameters on top of those of the Standard Model. 
You can check this video by Brian Greene and also this link.
