A theoretical model of a galaxy like the Milky Way,
showing trails of stars torn from disrupted satellite galaxies
that have merged with the central galaxy.
The structures seen in the SDSS-II star maps support
this prediction of a complicated outer Galaxy.
The region shown is about one million light years on
a side; the sun is just 25,000 light years from the
center of the Galaxy and would appear close to the center
of this picture.
Credit: K. Johnston, J. Bullock