Dr. David Stevenson is the Marvin L. Goldberger Professor of Planetary Science at the California Institute of Technology and an expert on the origin, evolution, and structure of planets. He is a New Zealander who came to the United States as a graduate student, obtaining a Ph.D. in theoretical physics at Cornell University in 1976, where he worked on the interior of Jupiter. Most of his subsequent career has been in the USA and he has been on the faculty at Caltech since 1980, serving as a Division Chair and Chair of the Faculty along the way. His research highlights include the development of the idea that Jupiter and Saturn have helium rain deep down, proposed explanations for the magnetic fields (or their absence) for planetary bodies, identification of an ocean in Europa by magnetic field measurements, explanations for both the remarkable similarities and some differences between the Earth and the Moon, and an explanation for why Venus has no moon. His awards and honors include membership in the National Academy of Science, Fellow of the Royal Society (London), the Urey Prize (awarded by the American Astronomical Society) and the Hess Medal (awarded by the American Geophysical Union). On occasion, he has participated in advising movie and TV directors on the science in their productions.
 

Chris Stringer has worked at The Natural History Museum London since 1973, and is now Research Leader in Human Origins and a Fellow of the Royal Society. His early research was on the relationship of Neanderthals and early modern humans in Europe, but through his work on the “Out of Africa” theory of modern human origins, he now collaborates with archaeologists, dating specialists, and geneticists in attempting to reconstruct the evolution of modern humans globally. He has excavated at sites in Britain and abroad, and is currently co-directing the Pathways to Ancient Britain project, funded by the Calleva Foundation. He has published over 200 scientific papers, and his recent books include The Complete World of Human Evolution (revised edition 2011, with Peter Andrews), the award-winning Homo Britannicus (2006), The Origin of Our Species (UK 2011), alternative title (US, March 2012): Lone Survivors: How We Came to Be the Only Humans on Earth, and Britain: One Million Years of the Human Story (2014, with Rob Dinnis).
 

Dr. Stephen Ressler is Professor Emeritus at the United States Military Academy at West Point and a Distinguished Member of the American Society of Civil Engineers (ASCE). A registered Professional Engineer in Virginia, he earned a B.S. from West Point, M.S. and Ph.D. degrees in Civil Engineering from Lehigh University, and a Master of Strategic Studies from the U.S. Army War College. He served for 34 years as a commissioned officer in the U.S. Army Corps of Engineers and retired at the rank of Brigadier General in 2013. While on active duty, he served in a variety of military engineering assignments around the world. In 2007, he deployed to Afghanistan to create a civil engineering program for the newly created National Military Academy of Afghanistan in Kabul.

Dr. Ressler is passionate about communicating the joys of engineering to inquiring minds of all ages. His three video lecture series — Understanding the World’s Greatest Structures, Understanding Greek and Roman Technology, and Everyday Engineering — are among the most highly-rated offerings in The Great Courses’ 600-course catalog. He served as an on-screen expert for the Discovery Channel documentary Superweapons of the Ancient World: The Ram and Blink Films’ The Real Trojan Horse, which aired on PBS in 2015. His award-winning Bridge Designer software has been used by over two million middle-school and high-school students worldwide. He is also a developer and principal instructor for the ASCE Excellence in Civil Engineering Education Teaching Workshop, which has provided teacher training to more than 500 civil engineering faculty members from over 200 colleges and universities.

Dr. Ressler has received numerous national-level awards from the ASCE and the American Society for Engineering Education (ASEE), including the 2011 ASCE Outstanding Projects and Leaders Award — the society’s highest honor.
 

Max Tegmark Tegmark is a Professor of Physics at MIT, co-founder of the Future of Life Institute and Scientific Director of the Foundational Questions Institute. His research has ranged from cosmology to the physics of cognitive systems, and is currently focused at the interface between physics, AI, and neuroscience. He is the author of over 200 publications and the book Our Mathematical Universe: My Quest for the Ultimate Nature of Reality. His work with the Sloan Digital Sky Survey on galaxy clustering shared the first prize in Science magazine’s “Breakthrough of the Year: 2003.”