1940

Milestones

• Mount Palomar Observatory construction advances

  Work continued on the 200-inch Hale telescope on Palomar Mountain in California, its enormous pyrex mirror having been cast and ground over the preceding years. The telescope would not see first light until 1948; the war had sent many of the scientists who would have used it elsewhere, and the mountain itself was briefly darkened for fear of Japanese aircraft using its light as a navigation aid.

  Astronomy/Space

• Chain Home radar proves decisive in the Battle of Britain

  The Chain Home network of tall radio masts along Britain's eastern coast, operational since 1937, gave Fighter Command an average of four minutes' warning of approaching German aircraft — enough, in most cases, to scramble and climb. It was technically inferior to the best German radar of the period; what it had was integration, the ability to feed its reports to controllers who could direct aircraft precisely. Technology and organisation together did what either alone could not.

  PhysicsTechnology

• Early computer development accelerates under wartime pressure

  The Bombe, an electromechanical machine designed by Alan Turing and Gordon Welchman at Bletchley Park, came into operation in 1940, tasked with breaking Enigma-encrypted German messages. It was not a computer in the modern sense but it was a logical machine that could eliminate wrong answers faster than human beings — and faster, it turned out, than the war could move.

  Technology

• Penicillin production scaled for wartime use

  Howard Florey and Ernst Chain at Oxford had purified penicillin in 1940 and demonstrated it could cure bacterial infections in mice, then in a small number of human patients. The challenge was growing enough of it — the mould produced the substance in frustratingly small quantities. By year's end the race to scale production had begun, driven by the straightforward calculation that war produces a great many infected wounds.

  Medicine