Among the other reasons listed in the thread, we can take lots and lots and lots of photographs of it from our southern hemisphere, and stitch the photos togeth

Among the other reasons listed in the thread, we can take lots and lots and lots of photographs of it from our southern hemisphere, and stitch the photos together into a composite, and compare such composites with the many many many distant galaxies we can see in the sky, many of which are disk like and presented at various degrees of edge-on-ness versus face-on-ness. Although we cannot be totally certain, the Milky Way is consistent with being a barred spiral galaxy, as it looks very much like what you get when you tilt a not-quite-edge-on view of a distant barred spiral galaxy into a completely edge-on view. Here's one of my favourite composites. Check out the 4000 x 1212 pixel version. https://en.wikipedia.org/wiki/File:Milky_Way_Arch.jpg https://en.wikipedia.org/wiki/File:Milky_Way_Arch.jpg And here's one of my favourite non-composites: http://apod.nasa.gov/apod/ap150730.html http://apod.nasa.gov/apod/ap150730.html Finally, here's a small patch of sky with a lot of various disk-like galaxies at random face-on-vs-edge-on tilts. https://en.wikipedia.org/wiki/File:Hubble_ultra_deep_field_high_rez_edit1.jpg https://en.wikipedia.org/wiki/File:Hubble_ultra_deep_field_h... Long exposure times, carefully stabilized equipment, and even moving the equipment outside the atmosphere have been a boon in producing these types of images.