Template:Are You Sure/October 23
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• ... that physicist and engineer William D. Coolidge made major contributions to X-ray machines; and that Coolidge developed ductile tungsten for incandescent light bulbs?
• ... that physicist and academic Tullio Regge and G. Ponzano developed a quantum version of Regge calculus in three space-time dimensions now known as the Ponzano-Regge model, and that this was the first of a whole series of state sum models for quantum gravity known as spin foam models?