Terzan 5 Is Old Remnant of the Ancient Milky Way

Using ESO’s Very Large Telescope, the NASA/ ESA Hubble Space Telescope and the Keck Telescope, scientists have discovered Terzan 5, an unusual globular star cluster that does not look like as any other globular cluster. Namely, it contains two groups of stars, one of 12 billion years of age and other population that is 4.5 billion years old.