Milky Way Galaxy
[Key Words]
[General] [Where
Are We?]
General
The Milky Way galaxy is probably the best known galaxy.
This is because it is our home galaxy. It is a spiral galaxy with
four arms. Each arm has its own name: the outer arm, the Perseus
arm, the Orion arm, and the Sagittarius arm.The Milky Way is
about 100,000 light-years across and 2,000 light-years thick.
There is a fountain of anti-matter
containing positrons spraying upward from the center of the
galaxy.
The center of our galaxy is obscured by interstellar
gas and dust. Visible light cannot pass through, although radio
waves and inferred light can pass through. Until this discovery,
we had no pictures of what the center of our galaxy looked like.
The center of our galaxy may contain a black hole.
The reason that our galaxy is called the Milky Way is because in
ancient times, when people looked up and saw the edge of our
galaxy, it looked like a river of milk because of all the stars
that are visible in that region.
Where Are We?
Our solar system is located 30,000 light-years from the
center of our galaxy. We are revolving around the galaxy at 137
miles per second. It takes over 200 million years to make one
rotation around the center of the galaxy. Our galaxy is part of
the Local
Group, which is a cluster that contains other galaxies. The
Local Group is part of the Local
Supercluster, which contains other clusters. Superclusters
are separated by large voids of space. Some astronomers believe
that these voids really contain galaxies and clusters full of dark
matter.
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[Key Words]
[General] [Where
Are We?]
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