Galaxies: Collisions, Types & Other Facts If you gaze out into
the night sky with a telescope, and see beyond what’s visible to
the naked eye, you could see a lot of “stars” that are actually
imposters. Many of the points of light we often think are
individual stellar objects are actually galaxies, collections of
millions to trillions of stars. Galaxies are composed of stars,
dust, and dark matter, all held together by gravity. Below we
discuss galaxy formation, galactic collisions and other facts
about these so-called “island universes.” Galactic & Black Holes
Galaxies come in a variety of shapes, sizes, and ages. Many have
black holes at their centers. In some cases, a galaxy’s central
black hole is extremely large or active, it’s surrounding area
producing a tremendous amount of energy that astronomers can see
over great distances. Material circling the black hole may be
accelerated outward by its jets. Other galaxies may contain
objects like quasars, the most energetic bodies in the universe,
at their cor