Word: ultrashort
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...shoot radio waves at the moon and get a faint echo. The Signal Corps did it first in 1946, and even radio hams do it now. But dependable communication by lunar reflection is harder. The Signal Corps and its collaborator, Collins Radio Co. of Cedar Rapids, Iowa, use ultrashort waves (810 megacycles, 37 cm.) because they pass without much loss of energy through the ionized layers in the high atmosphere...
...Dirac theory predicts, among many other things, that hydrogen atoms can exist in two different "states"-one stable, the other unstable-which contain the same amount of energy. Lamb & Retherford checked up with ultrashort radio waves (war-developed for radar), and found that this prediction was not correct...
...watt ultrashort-wave transmitter could weigh less than 50 lbs., said Dr. Hutcheson, and its signal would be strong enough to reach from moon to earth, even without the advantage of a directional beam. Power could come from batteries. The whole apparatus would have to be designed to deal with the vacuum of space, and designed to operate both in extreme cold and in the high temperature (250° F.) of the lunar midday. To Dr. Hutcheson such difficulties were minor...
ASDIC, designed for submarine hunting, sends ultrashort sound waves through the water and any sizable object reflects them. During the war, this fact frequently caused depth-bombing of whales, torpedoing of schools of pilchards. But as ASDIC and its operators improved, they learned to distinguish skillfully between echo-making objects, could even tell big from little fish...
Radar operators during the war were frequently worried men. They worked with novel transmitters which sent out powerful beams of little-known ultrashort waves. What effect might these have on human flesh and blood? Some servicemen feared alopecia (loss of hair) or leucopenia (loss of white corpuscles). But most of all they talked about sterility. A few demanded lead pants or jockstraps...