A rich starry sky fills the view from an ancient gas-giant planet in the core of the globular star cluster M4. The 13-billion-year-old planet orbits a helium white-dwarf star and the millisecond pulsar B1620-26, seen at lower left. The globular cluster is deficient in heavier elements for making planets, so the existence of such a world implies that planet formation may have been quite efficient in the early universe. (Photo by Reuters/NASA)
