Expansion

[martin_h]

We all know of the analogy of the dots on a baloon "moving" apart as the baloon expands, but what if the dot is a circle? the circle expands as well - yes?

So I was thinking (like you do) are galaxies expanding too, or are they prevented by the inherent gravity within?

[Adrian]

Yes - they are expanding. The space between the Earth and the Sun is expanding, the space that the atoms in your body are situated in is expanding. Fortunately the same thing is happening to the tape measure

Indeed, one theory of how the universe ends is that the expansion rate (hubble constant) accelerates over time until not even fundamental particles can hold together over the speed of expansion and everything flies apart (the big rip)

Ultimate fate of the universe - Wikipedia, the free encyclopedia

[George Jones]

We all know of the analogy of the dots on a baloon "moving" apart as the baloon expands, but what if the dot is a circle? the circle expands as well - yes?

So I was thinking (like you do) are galaxies expanding too

No.

or are they prevented by the inherent gravity within?

Yes. I better analogy for our current cosmological era would be small coins glued to the surface of the balloon. As the balloon expands, the coins don't expand.

The space between the Earth and the Sun is expanding, the space that the atoms in your body are situated in is expanding. Fortunately the same thing is happening to the tape measure

This stuff is also not expanding during our current cosmological era.

Indeed, one theory of how the universe ends is that the expansion rate (hubble constant) accelerates over time until not even fundamental particles can hold together over the speed of expansion and everything flies apart (the big rip)

Ultimate fate of the universe - Wikipedia, the free encyclopedia

Yes, the accelerating expansion of the universe eventually wins, even without a big rip, but, even though the acceleration of the universe is currently expanding, the value of the Hubble constant is currently decreasing.