re: 100,000 ly- not 75,000
The Milky Way galaxy is a large spiral galaxy of Hubble type SBbc (loosely wound barred spiral) with a total mass of about 1012 solar masses (M☉), comprising 200-400 billion stars (see [3]). The galactic disk has a diameter of about 100,000 light-years (see 1 E20 m for a list of comparable distances). The distance from the Sun to the galactic center is about 27,700 light-years.
http://en.wikipedia.org/wiki/Milky_Way