The Universe
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The Local Group is a cluster of approximately
30 galaxies that spans nearly 2 million light
years.  The group is dominated by three main
galaxies: Andromeda M31, the Milky Way, and
Triangulum M33.

Each of these major galaxies possess
numerous satellite galaxies, and together
they form a vast "cloud" known as the Local
Group.

The structure of the group is most likely
unstable.  Calculations suggest these group is
highly dynamic, and has probably changed
significantly in the past.  It is generally
believed that in the distant future,
Andromeda and the Milky Way will collide,
creating a massive elliptical galaxy containing
tens of billions of stars.

The Local Group, however, is not isolated.  It
is instead in gravitational interaction and
member exchange with countless nearby
Groups.  These include:  Maffei-1 Group,
Sculptor Group, M81 Group, and M83 Group.  
Combined with the Local Group, these
numerous galaxies form immense chains of
galaxies that wrap around a much larger
structure known as the Virgo Cluster.
The Virgo Cluster is a giant conglomeration of
some 2,000 galaxies, and is situated nearly 60
million light years away.  It is the physical
center of an immense group of nearby
galaxies known as the Local Supercluster, of
which the Milky Was is a member.  So massive
is the Virgo Cluster, it influences
all nearby
galaxies and groups with its intense
gravitational pull.  The Local Group has
experienced a notable acceleration toward
the Virgo Cluster, but it is not yet known if
the gravitational forces are sufficient to
devour the Local Group.
The Virgo Cluster, however, is merely a minor
member of a much larger whole.  The
neighboring superclusters are massive, most
of them three and four times larger than the
Virgo Cluster and spanning a distance of some
100 million light years.  These leviathans in
turn form massive chains and walls that
weave throughout the cosmos.  Between
them exists, quite literally, nothing.  These
giant voids are hundreds of millions of light
years in diameter and most of them contain
absolutely nothing at all.  No stars.  No galaxy.
No matter.

These immense chains of  galactic super-
clusters are constantly in motion.  Not only
are gravitational forces causing interaction
between the numerous galaxies, they are all
of them speeding toward an even more
massive entity known as the Great Attractor.

The Great Attractor is an unseen force of
nature.  Its location and composition are
both unknown, but it is believed to be a
massive conglomeration of dark matter...
perhaps containing 10 times more than the
total amount of visible matter in the nearby
universe.