How can we know we are a Spiral galaxy?

Question

Even our solar system is vast, where do we get the proof of our spiral galaxy?

In: Planetary Science

Answer 1

We look at the density of the stars and the distance for those we can measure. We also can see other spiral galaxies and from that infer how it would look like if we are inside such a galaxy. The fact that it is at least disc shaped can be seen with your own eyes on a proper dark night. ( And no clouds obviously).