Cosmic Dawn

Pinning down the origin and nature of the first stars

Most parents will tell you that the arrival of their firstborn was a life-altering event. Abraham Loeb, a first-time father and cosmologist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., is no exception. Standing in front of an audience of NASA astronomers one recent Friday afternoon, Loeb begins his lecture by flashing a slide of his 1-year-old daughter, Klil.