The Milky Way

''"I can never look now, at the Milky Way without wondering from which of those banked clouds of stars the emissaries are coming."  Arthur C Clarke''

The Milky Way
The Milky Way galaxy is a barred spiral galaxy located in the Virgo Supercluster, which is located in the Laniakea Supercluster.

The main body of the galaxy is approximately 100,000 light years across, but solar systems are attached to the galactic disk as far as 100,000 light years from the centre. The galaxy is relatively flat, peaking at a thickness of 2,000 light years in the centre.

The Galaxy contains four primary spiral arms rotating around a central bar or bulge of celestial objects: Perseus; Sagittarius; Centaurus and Norma Arms. The Orion Spur is a smaller arm sandwiched between the Perseus and Sagittarius arms.

The Galaxy is spinning, at a rate which means a revolution is completed in roughly 225,000,000 years. The rotation of the galaxy is used as a fixed frame of reference when considering  astro-cartography and used for calibration of the galactic calendar.

Whilst cartographers have mapped a region of space roughly a billion cubic light years in volume, this represents an insignificant portion of the galaxy.