I wanted to share a remarkable new Hubble Space Telescope image with you. In the accompanying picture, you see a magnificent cluster of over 250,000 stars, a grouping whose catalog number is M9. (This designation comes from a list Charles Messier made long ago of fuzzy objects of interest in the sky.) The colorful cluster is in the direction of the center of our Milky Way galaxy, some 25,000 light years away. (This means that, traveling at the speed of light, it would take you 25,000 years to travel there!) What's fascinating about this Hubble image -- taken with the Advanced Camera for Surveys -- is how clearly we can see individual stars in this crowded, distant group. (The cluster is so far away and so small that it takes up about as much of the sky as the head of pin, held at arms' length.)
The stars in this cluster are typically older than the Sun and contain fewer of the heavier elements that make life and technology on Earth possible. Such clusters, called globular clusters, are thought to be among the oldest objects in our Milky Way Galaxy. We study the globular clusters like M9 to learn more about the archaeology of our home galaxy and how things were in our neighborhood long before the Sun and the Earth ever existed.