How can the gravitational force compress mass into a singularity if gravity is the weakest of the forces? Gravity is the weakest force. I’m curious, what is the explanation for how gravity overcomes other forces and squeezes a mass down to a singularity? I get the idea of the outward pressure of fusion ceasing and the star collapses, but I would expect the other forces to arrest the collapse before it can reach a singularity. 
 A: Two things to bear in mind:


*

*Gravity is always attractive. There is no such thing as negative mass.

*There's no upper limit on how much mass we can have.


Once we have those two we can make an object collapse into a singularity - just add more mass. It's always attractive, compressing the object, and there's no limit to how much mass we can add. 
Compare vs. the electromagnetic force. Say you have an electron. If you add another electron, you get repulsion, so you don't get collapse. A proton would attract the electron, but then you'd get a neutral mixture, meaning no more electromagnetic force. Gravity has no such issues, and the total gravitational force exerted by the mixture has increased. If you keep adding electrons and protons, there's still no electromagnetic force, but you'll eventually get a gravitational singularity.
A: Yes, you are thinking correctly, gravity actually is quite weak when collapsing. And that is the specific reason why only massive stars undergo complete gravitational collapse.
If its a normal massed star, like our sun, then it doesn't undergo complete gravitational collapse. Electron degeneracy pressure holds it, which is just because of the Pauli Exclusion Principle (Electrons being fermions cannot occupy, or rather, don't want to occupy the same state - causing a pressure to separate them when gravity collapses them). At that temperature, electromagnetic force basically becomes redundant (A white dwarf is very very hot).
After the Chandrashekhar limit of $1.44\ solar\ masses$, a white dwarf is unstable as grvaity becomes stronger than the electron degeneracy pressure, and it collapses into a supernova (and then maybe a neutron star or a black hole.)
Stars with approximately mass between $1.44\ and\ 25\ solar\ masses$ go off as supernova and the remnants are kept intact from gravitational collapse by neutrons - neutron degeneracy pressure starts working. This is called a neutron star.
Beyond the $25\ solar\ mass\ limit$, the remnant has no force capable of counteracting gravity, and it rapidly collapses into a singularity, our so called black holes.
So yes, you are right, and your thinking, if turned into mathematical equations, will lead to the mass limits i have specified.
Cheers!!
