Palomar 6: Globular Star Cluster

© ESA/Hubble and NASA, R. Cohen

Where did this big ball of stars come from? Palomar 6 is one of about 200 globular clusters of stars that survive in our Milky Way Galaxy. These spherical star-balls are older than our Sun as well as older than most stars that orbit in our galaxy's disk. Palomar 6 itself is estimated to be about 12.5 billion years old, so old that it is close to — and so constrains — the age of the entire universe. Containing about 500,000 stars, Palomar 6 lies about 25,000 light years away, but not very far from our galaxy's center. At that distance, this sharp image from the Hubble Space Telescope spans about 15 light-years. After much study including images from Hubble, a leading origin hypothesis is that Palomar 6 was created — and survives today — in the central bulge of stars that surround the Milky Way's center, not in the distant galactic halo where most other globular clusters are now found.

Based on Astronomy Picture Of the Day.