eli5: if everything in the universe is constantly revolving at insane speeds, why are the constellations and star patterns the same all the time?
In: Physics
They’re not the same all the time – the stars and constellations look different now than they did thousands of years ago, and will look different in thousands of years from now. I should say look noticeably different. With incredibly precise instruments, constellations look different over much shorter time scales.
The reason the stars appear unchanging is because they are so far away and the distances between them so vast that they seem locked in place even as they careen in all different directions. It’s akin to the apparent speed of a jet flying a few hundred feet overhead and one flying a few miles up – they’re moving at the same speed, but the distance changes your perception of movement and speed. Scale that up a billion-fold or a trillion-fold (or more) and you get the unchanging heavens effect you describe.
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