eli5 If we are a spinning ball – spinning in our own solar system – which is spinning within an arm of a galaxy – why are the constellations in the same place?

Question

eli5 If we are a spinning ball – spinning in our own solar system – which is spinning within an arm of a galaxy – why are the constellations in the same place?

In: Physics

Answer 1

In addition to the other comments, we can only see stars within our own galaxy. Even if we could see further, the rotational period of the galaxy is stupid long. A quick google shows it as around 240 million years. One of the earliest records of human civilization goes back around 5500 years, and the earliest Homo sapien skeleton was dated back to around 200,000 years.

If we translate those into into % of a rotation or degrees, we get like, .002% or .007 degrees of rotation for almost all of recorded history, or .08% or .288 degrees in all of known human existence. The amount the constellations would vary from other galaxies would be really small.

Disclaimer: I am really bad at math.