system
Given the following post, respond as if you're commenting on Reddit:
human
Why do galaxies appear as consistent objects, given their sheer scale?

Wouldn't the closer part of a galaxy hundreds of thousands of light years across appear more like it is now than the far side of it? 

E.g. we'd be seeing the closer side as its rotated closer to now, but the further side as it rotated much longer ago, thus it shouldn't really look so consistent, like a pinwheel.
gpt
Hundreds of thousands of years is actually quite a short period of time in astronomy. Even very short-lived stars last for millions of years.

The distance to other galaxies is also much larger than their size. Andromeda, the closest large galaxy to us, is millions of light-years away. We can say many other objects that are *billions* of light-years away. On that scale, we definitely notice that closer galaxies are more evolved than more distant galaxies. But on the scale of an individual galaxy, a hundred thousand years is almost too small to notice.