Dirac Lecture 2 (of 4) - Quantum Electrodynamics

Can anyone help me with this question please? (UPDATE: Just Answered Aug 2014 - Big thanks to Brent Follin - PhD Student on Quora - who kindly persisted with me until I understood his answer. He supplied very Intuitive comments - Brent reminds me of this man filmed above!!!...) To solve the word’s energy crisis; find a star that’s emitted an infra-red photon. Just make sure the star you find is travelling sufficiently fast enough toward us so the photon is blue shifted into the gamma region far enough to ha