is believed that the great mass of the stars
are arranged in the
form of a lens- or bun-shaped system.
considerably flattened towards
the Sun occupies a fairly central position.
the galactic poles the density continues practically uniform up to a distance
of about 100 parsecs; after that the falling off becomes noticeable, so
that at 300 parsecs it is only a fraction (perhaps a fifth) of the density
near the Sun. [One parsec equals 3.26 light years.] The extension in the
galactic plane is at least three times greater. These figures are subject
to large uncertainties.