[Southack]

"You've made a geometrical argument why these velocities should be infinite in the case of gravity, but haven't explained why they aren't infinite in the case of electromagnetism. The geometry is the same, so why does your argument fail there?"

In all fairness, if I haven't made the argument for magnetism, how could it have failed there?

[Physicist]

In all fairness, if I haven't made the argument for magnetism, how could it have failed there?

The geometry of gravity and electromagnetism is the same in Newtonian physics. You have to explain why the same argument wouldn't apply. That you haven't tried to apply it so is neither here nor there: just because you dance around that third rail doesn't mean it isn't there for you. What is different? Why isn't electromagnetism an acceptable analogue, if it isn't? How can the orbits of charged particles in an EM potential be stable if it is, and if your argument has any merit?