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 can use telescope to see distant stars and analyse their light to know their distance. By plotting this on a map, we can see that stars are clustered into galaxies, and the stars within about 100,000 ly of us are arranged into a spiral galaxy.

One caveat is that the galactic core is dense with opaque dust, making it hard to know if ours is a bar galaxy, or what’s on the other side of the galaxy.