Omega Centauri: A Bright Old Star Cluster
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Discover space. Each day there is a new image of our universe. A short explanation is written by a professional astronomer.
Explanation: The globular star cluster Omega Centauri has about 10 million stars. These stars are much older than the Sun. They fit in a space about 150 light-years across.
It is also known as NGC 5139. It is 15,000 light-years away. It is the largest and brightest of about 200 globular clusters in the halo of the Milky Way galaxy.
Most star clusters have stars with the same age and composition. Omega Centauri shows different groups of stars. These groups have different ages and many chemical elements.
In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way.
Omega Centauri looks yellow. Its red giant stars are easy to see in this clear telescope view.
A twenty-year study with the Hubble Space Telescope has found evidence for a large black hole near the center of Omega Centauri.
APOD's email to submit images has changed. Please see APOD Submissions.
APOD's main NASA site is moving. It goes from apod. nasa.gov to science. nasa.gov/ apod.
Tomorrow's picture shows reflections on a starry night.
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