Think of it not as an explosion but rather like that expanding foam you buy at the hardware store to fill cracks and voids. Only this “universe foam” (spacetime) has been expanding for at least the past 14 billion years and at an accelerating rate.

The cosmic microwave background radiation is basically the glow of the big bang, and it’s very uniform. That means “things” were not “moving” at different speeds after the big bang.

Hmm. My (mis)understanding is that it isn’t as though the expansion comes from a central explosion that you might expect to throw small things faster than big things like shrapnel from an artillery shell -- rather, space itself has been expanding, carrying things along with it. It also seems to have been doing this…

I mean, the sun is still going to consume the planet long before then either way.