b'19Carnegies Las Campanas Observatory director Leopoldo Infante led the work (left). Team members, from left to right are Weida Hu, Junxian Wang, and Weiyong Kang from the University of Science and Technology of China. Images courtesy Leopoldo Infantethe neutral hydrogen to excite and lose electrons, agalaxies. The astronomers found evidence that process called ionization. This reionization endedheavier elements were rapidly assembling and were some 870 million years after the Big Bang. widespread in the early universe. Infante with Huan Yang and others are surveyingThe observations revealed that the Lyman-alpha young galaxies from the reionization era employingemitting galaxies are not distributed uniformly telescopes at the Cerro Tololo Inter-Americanin space. The astronomers believe that the early Observatory and at Las Campanas, both in Chile.supernovae explosions scattered some heavy The researchers studied the spectrum of light fromelements into the interstellar medium and that the collection of stars in the young galaxies, whichreionization occurred in differentiated zones or had not been observed until now. The light containsbubbles. It is as if the light is making its way through information about their chemical composition.windows scattered in space-time when the universe In particular, they looked for a spectroscopicand its structures were young, but oddly rich in heavy fingerprint called a Lyman-alpha emission, whichelements and full of electromagnetic and probably indicates prolific star formation in very distant, younggravitational waves.'