The Bridge V Learning Edition 1 ; our solar system | Page 53

Data provided in this activity
The data used in this activity is Hubble Space Telescope data of the Coma Cluster of galaxies. It
was taken in 2006 using the Advanced Camera for Surveys (ACS) instrument on the Hubble
Space Telescope.
Galaxy Environments
Galaxies are found throughout the universe, and live in a variety of environments. Galaxies can
be found in clusters, groups, or in isolation.
Groups
Sometimes galaxies are found in smaller numbers called groups, with just a handful of galaxies
being mem bers of the group. The Local Group contains our Milky Way galaxy, and our next door
neighbours the Magellanic Clouds and the Andromeda galaxy, along with a few dozen smaller
galaxies.
Field
At other times, galaxies can be isolated and be far from another in the field. These are called
field galaxies.
Clusters
A galaxy cluster is a large structure in the universe consisting of hundreds or thousands of
galaxies that are gravitationally bound together. The large number of galaxies in a cluster are
all packed close together, such as in the Coma Cluster. Clusters make some of the largest, and
densest structures in the universe. Clusters, groups, and some isolated galaxies can all be part
of even larger structures called superclusters; at the largest scales in the visible universe,
superclusters are gathered into filaments and walls surrounding vast voids. This structure is
often referred to as the ‘cosmic web’.
FULL ACTIVITY DESCRIPTION
Students will first investigate images of 40 galaxies to become familiar with how galaxies
appear and are shaped differently. They will come up with their own classification scheme for
galaxies, and then explore how astronomers actually classify galaxies into four main groups.
www.space-awareness.org