Free Astronomy Magazine November-December 2023

49 ter blue light, causing only the red- der wavelengths to come through to Earth. The interstellar dust clouds are mottled so that different parts of the cluster look redder than other parts along our line of sight. The brightest red stars in the photo are bloated, aging giants, many times larger than our Sun. They lie between Earth and the cluster. Only a few may actually be members of the cluster. The very brightest hot, blue stars are also along the line of sight and not inside the cluster, which only contains aging stars. Terzan 12 is one of 11 globular clus- ters discovered by the Turkish-Ar- menian astronomer Agop Terzan approximately a half-century ago. With its sharp vision, Hubble has revolutionized the study of globu- lar clusters ever since its launch in 1990. Hubble observations have shed light on the relation between age and composition in the Milky Way galaxy's innermost globular clusters. Hubble sees the glittering globular cluster Terzan 12 by NASA/ESA Ray Villard Bethany Downer T his colorful image of the glob- ular star cluster Terzan 12 is a spectacular example of how dust in space affects starlight com- ing from background objects. A globular star cluster is a conglom- eration of stars, arranged in a spher- oidal shape. Stars in globular clusters are bound together by gravity, with a higher concentration of stars to- wards the center. The Milky Way has about 150 ancient globular clusters at its outskirts. These clusters orbit around the galactic center, but far above and below the pancake-flat plane of our galaxy, like bees buzzing around a hive. The location of this globular cluster, deep in the Milky Way in the con- stellation Sagittarius, means that it is shrouded in gas and dust which absorb and alter the starlight ema- nating from Terzan 12. The cluster is about 15,000 light-years from Earth. This location leaves a lot of room for intervening interstellar dust particles between us and the cluster to scat- !