Time Machine Remains His Obsession To See Late Dad

Theoretical physicist Ronald Mallett stands for a photograph with a ring laser in a laboratory at the University of Connecticut in Storrs, Connecticut, U.S., on Monday, March 23, 2015. Mallett says he kept his work on time travel secret for years partly because colleagues would conclude he was a crackpot unfit for tenure. Photographer: Scott Eisen/Bloomberg via Getty Images