The globular cluster M13 in the constellation Hercules
Click on image for full size
the Space Telescope Science Institute and NASA
If you think that this globular cluster looks like a very round elliptical galaxy
, you would
be right! Elliptical galaxies and globular clusters have a lot in
common. There is no gas or dust in a globular cluster, and the stars
are old. In fact, some evidence suggests that globular clusters were
the first objects to form.
The big difference is size! Globular clusters contain hundreds of
thousands or millions of stars. Elliptical galaxies can contain
hundreds of billions of stars! And while elliptical galaxies are
sometimes round, globular clusters are never elliptical.
Globular clusters are found both in spiral galaxies and elliptical
galaxies. The Milky Way,
for example, has over one hundred globular clusters throughout it's
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