Guest Stars Sally Dexter as Older Mileva T.R. Knight as J. Edgar Hoover David Dencik as Niels Bohr Jodhi May as Helen Dukas Nikola Djuricko as Leo Szilard Joshua Akehurst as Hans Albert Einstein (Age 15) Neal Huff as Robert Oppenheimer Ed Stoppard as Adult Hans Albert Einstein Michael Lindall as Agent McKee Aidan McArdle as Dr. Thomas Harvey Dixie Egerickx as Alice Edwards Joseph Arkley as David Bohm Co Starring Nancy Crane as Eleanor Roosevelt Sinéad Phelps as Secretary Roy McCrerey as Committee Chair Bob Karper as Field Director Kit Ross as Younger Albert Einstein Joshua Glenister as Bernhard Einstein Carla Dixon as Evelyn Einstein Magnus Af Sandeberg as Male Secretary MaryKathryn Kopp as Nurse Howard Lotker as Reporter Markus Pfeiffer as Young Hermann Einstein Jasmin von der Born as Frieda Einstein Cornelius Geaney, Jr. as Assistant Director Andrew Boyer as Doctor Gary Fannin as Technician Stewart Alexander as Harold Urey Bob Boudreaux as Congressman Rankin