<P> The Milky Way is the second - largest galaxy in the Local Group , with its stellar disk approximately 100,000 ly ( 30 kpc ) in diameter , and , on average , approximately 1,000 ly ( 0.3 kpc ) thick . As a guide to the relative physical scale of the Milky Way , if the Solar System out to Neptune were the size of a US quarter ( 24.3 mm ( 0.955 in ) ) , the Milky Way would be approximately the size of the continental United States . A ring - like filament of stars wrapping around the Milky Way may belong to the Milky Way itself , rippling above and below the relatively flat galactic plane . If so , that would mean a diameter of 150,000 -- 180,000 light - years ( 46 -- 55 kpc ) . </P>
<P> The Milky Way is the second - largest galaxy in the Local Group , with its stellar disk approximately 100,000 ly ( 30 kpc ) in diameter , and , on average , approximately 1,000 ly ( 0.3 kpc ) thick . As a guide to the relative physical scale of the Milky Way , if the Solar System out to Neptune were the size of a US quarter ( 24.3 mm ( 0.955 in ) ) , the Milky Way would be approximately the size of the continental United States . A ring - like filament of stars wrapping around the Milky Way may belong to the Milky Way itself , rippling above and below the relatively flat galactic plane . If so , that would mean a diameter of 150,000 -- 180,000 light - years ( 46 -- 55 kpc ) . </P>
what is the thickness of the milky way
what is the thickness of the milky way
approximately 1,000 ly ( 0.3 kpc )
approximately 1,000 ly ( 0.3 kpc )