Gregory Bothun is a physics professor at the University of Oregon in Eugene and author of Cosmology: Mankind’s Grand Investigation.

Yun Wang is an associate professor of physics and astronomy at the University of Oklahoma in Norman.

Ina Sarcevic is a physics professor at the University of Arizona in Tucson and author of The Edge of Infinity. Read an article she wrote on the fundamental nature of matter.

Andrew J.S. Hamilton is professor of astrophysicial and planetary sciences at the University of Colorado in Boulder. He teaches courses on cosmology, astrophysics, and astronomy and is an expert on black holes.

Barbara Sue Ryden is an associate professor of astronomy at Ohio State University in Columbus, author of Introduction to Cosmology and co-author of Basic Astrophysics (2008).

Christopher S. Kochanek is an astronomy professor and Ohio Eminent Scholar in Observational Cosmology at Ohio State University in Columbus. He is an expert in cosmology.

Marco Cavaglià is assistant professor of physics and astronomy at the University of Mississippi in Oxford. His research interests include cosmology, string and M-theory cosmology, and quantum cosmology.

Robert J. Scherrer is a professor and chairman of the department of physics and astronomy at Vanderbilt University in Nashville, Tenn. His research focuses on cosmology and the structure of the universe. He also blogs about science and science fiction and is an expert on the big bang theory, dark matter and dark energy.

John F. Hawley is a professor and chairman of the astronomy department at the University of Virginia in Charlottesville. He co authored Foundations of Modern Cosmology (2nd edition, 2005).