The expanding Universe and Galactic collisions

The relative velocities of different stellar objects are greater in magnitude than the rate of expansion.That's all there is to it really.

Is it increasing? I thought that was still being determined. Either case, doesn't matter. Gravity is massively more powerful than expansion. Everywhere. At t=0 (the bang) every point in the universe is in the same place. You're thinking of it like an explosion; it isn't like an explosion. There wasn't a bunch of space into which there was a big explosion. Fortunately all the scientists would agree with you. Have a read through the Wikipedia article on it.

It produces a more powerful force, no? I'd call that more powerful. It's the pervasiveness of expansionary effects that makes them more significant over larger scales, not their power. In the same way that the strong force is much more powerful than the gravitational force, but acts only over very short distances and so, on a larger scale, gravity comes to dominate.

Yes, that's not what I was trying to say. As I understand it, modelling gravity as a force is not quite accurate either, but both can be reasonably simplified to such - more precisely if you treat gravitational effects as curvature of spacetime, the expansion is modelled as a reverse curvature (if you treat expansion in the same way as the cosmological constant) and this can then be simplified to a force model. But, I'm neither a Physicist nor a Cosmologist, so I'm open to correction.

I suspect if you can answer that question, and provide proof for your answer, there's a nobel prize in it for us.

There is no "outside the universe"; the concept is meaningless.

Imagine a big sheet of rubber being stretched. Now imagine two ants crawling towards each other across that sheet. Each point on the sheet is moving away from each other, but the ants are moving with respect to those points. Providing the ants are crawling faster than they're being moved apart by the sheet they can still reach each other.

You've missed out half the argument, being asked "who created God" is what is known as being hoist by your own petard, it goes like this:T: "Nothing can exist without a cause so God exists!"
A: "If nothing can exist without a cause, what cause God?"
T: "He's magic. It doesn't apply."