Wei Zheng （郑玮）is a Principal Investigator of the Physics Department of Johns Hopkins University. He received his BS from the Fudan University and PhD from the University of California at San Diego. His main research is on quasars and galaxies in the very early Universe. He participated in multiple NASA projects and was the first to propose a deep near-infrared survey from space (PRIME). With more than 300 publications, his main contributions include a HST quasar composite spectrum, the discovery of primordial helium, gravitation lensing and the young galaxies at redshifts around 10.Quasars are the most energetic objects in the Universe, and their spectral properties have been studied extensively. One remaining mystery is their ages: What quasars are considered young, and what spectral characteristics do they have?The Lyman-alpha forest lines in most quasars at redshifts approximately 3 display a proximity effect: the reduced line numbers in the quasars’ high-ionization bubbles. A group of these quasars show a weak proximity effect, suggesting that their bubbles have not been fully developed because of young ages. Noticeable difference in emission lines is found between young and old quasars. It is likely that the quasar line properties are not only affected by viewing angles, but also by their ages.