In his Bad Astronomy blog post today, Phil Plait describes a new and exciting explanation for why spiral galaxies get all spirally. It’s a good article and of course I think you should read it.
BUT what occurrs to me as being pretty cool is that in the diagram of our Milky Way Galaxy that Plait includes in his post is a cute little circle on the diagram showing where “Our Sun” (and our solar system and therefore all of us) are located.
See that cute little circle next to the “Our Sun” lable? That’s about the size of the region of our galaxy within which every star visible to the naked eye resides.
Galaxies are big.