What Happens When You Increase an Extremal Black Hole's Charge?

[kcajrenreb]

If you were to greatly increase the elctrical charge of an extremal Black Hole, (ie, drop a lot of electron in) what exactly would happen to it? I know the electrical repulsion would become more powerful than the gravity, so would it tear itself apart?

 

[Drakkith]

I've never heard of the electromagnetic force overcoming the gravitational pull of a black hole. Are you sure about that?

 

[kcajrenreb]

I've never heard of the electromagnetic force overcoming the gravitational pull of a black hole. Are you sure about that?

Yes, well, its a hypothetical situation, but it can certainly happen.

 

[zhermes]

If you were to greatly increase the elctrical charge of an extremal Black Hole, (ie, drop a lot of electron in) what exactly would happen to it? I know the electrical repulsion would become more powerful than the gravity, so would it tear itself apart?

If you just added more electrons to it, it would just stay an extremal black-hole with a larger charge and mass... if you magically added only charge, and not mass---well, GR says you can't do that.

I've never heard of the electromagnetic force overcoming the gravitational pull of a black hole. Are you sure about that?

Its not quite as simple as EM 'overcoming' gravity, nothing can 'overcome' the gravity. But you can get very exotic spacetime geometries... perhaps even naked singularities according to some loop quantum gravity, and pure GR extrapolations...

 

[twofish-quant]

If you just added more electrons to it, it would just stay an extremal black-hole with a larger charge and mass... if you magically added only charge, and not mass---well, GR says you can't do that.

Specifically imagine that you add a lot of electrons to the black hole. The electrons all have negative charges so they are repelling each other. However, those negative charges have stored potential energy and that energy has an equivalent mass (E=mc^2).

So if you try to add enough charge to blow the black hole apart, what happens is that that charge has potential energy which has mass which has gravity which keeps the black hole together.

 

[kcajrenreb]

Specifically imagine that you add a lot of electrons to the black hole. The electrons all have negative charges so they are repelling each other. However, those negative charges have stored potential energy and that energy has an equivalent mass (E=mc^2).

So if you try to add enough charge to blow the black hole apart, what happens is that that charge has potential energy which has mass which has gravity which keeps the black hole together.

Thanks.