How is the Universe Expanding?

[Rhondazvous]

static universes (ones that neither expand nor contractor) are not stable, so it's one or the other. At least in regards to having a universe with beings inside to contemplate WTF is going on.

atoms are small and sturdy enough regardless of when they form the expansion will not inflate them (disregarding for the moment some theoretical work that might change that in a distant epoch of this universe)

as a whole, and in isolation, galaxies are stable for VERY long time periods, HOWEVER, as, for instance, our sun orbits our galaxy, it is radiating gravitational energy, and it's orbit is contracting excruciatingly slowly.  Wait long enough and if nothing else intervenes, we are going to be absorbed into the central black hole, or something else between here and there.

the long term (until the sun burns out) stability of our solar system is in a slight amount of question.  The long term (billions of years) stability of the planet Mercury's orbit is slighty suspect, and it might, if we wait long enough, experience a cranking up of it's orbital eccentricity and collide with Venus, or, mush less likely, earth.

Additionally, IIRC, in some billions of years, it is expected earth might achieve an orbital resonance with Saturn.  I don't recall what happens then other than it would be unpleasant.

Doesn't bode well for long term investments. It's enough to get Wall Street scrambling.