In the 1930s, it was widely believed that interception of enemy bombers before they reached their targets was practically impossible. As Stanley Baldwin said “The bomber will always get through.”
But the British development of what we now call radar (the American term) completely changed the calculus. Enemy bombers could be detected while they were still hundreds of miles away, which might give barely enough time to stop them.
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Fanfare
Opening War Theme
Goldberg Variations
Composed in 1741 by Johann Sebastian Bach. Public domain.
Performed by Shelley Katz. Public domain recording. Source.
Closing War Theme
Except when otherwise indicated, the contents of this podcast are © and ℗ 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, and 2023 by Mark Painter, all rights reserved. Some music and sound effects used by arrangement with Pond 5.
Just gotta comment: The inverse-square law was routinely invoked for decades to _prove_ that those silly science-fiction ideas of ray guns and beam weapons violated fundamental physical laws.
Then came lasers (and analogous devices in other wavelengths), which are not subject to the inverse-square law. The waves are traveling in parallel in lockstep, and spread only slightly due to imperfections in the means by which they’re generated (i.e., they’re not _exactly_ parallel). This is why you’re now hearing serious talk of beam weapons.
Of course, the Nazis didn’t have a laser–for which we can be grateful!–but the bogus “proof” of the impossibility of a death ray was simply dumb luck. Watson-Watt’s team either didn’t realize that the inverse-square law applies only to thermally generated (“black body”) emissions, or if they did, they assumed alternative emission mechanisms weren’t possible. And they were wrong.
Maybe there’s a moral here…
You’re right about the applicability of the inverse-square law. If I recall correctly, someone wrote a science fact article for Astounding Science Fiction in 1960, reiterating the argument against beam weapons. The article appeared just months before the first working laser was announced.
The theoretical foundation for coherent beams was already in place in 1935, though I doubt more than a few people had thought about it. It might have been possible for a German researcher to hit on the idea then, though I have reservations about whether anyone could build a laser with 1935’s off-the-shelf technology. (“Stone knives and bearskins” is what Mr. Spock called it.)
Even if they could have, I would note that it is now 63 years since the first laser, and although lasers are in 2023 an everyday technology, they are used almost exclusively for reading and writing data. Lasers as weapons are still in the experimental stage. So we can’t criticize Watson-Watt and his team too harshly.
To be sure, a laser in the 1930s would be an exceedingly long shot–but that’s not the same as impossible. The problem with deciding something’s “impossible” is that you can _really_ get blindsided when it turns out it isn’t!
In any case, lasers are also currently used routinely for cutting in precision machining, and in surgery, so it doesn’t seem a great conceptual step from such applications to weaponry. I would suspect there’s a large element of historical contingency involved as to why weapons-grade lasers are still experimental at present.
I tried to track down that 1960 article you mentioned, but with no success. The closest thing I could find is an uncredited editorial, probably by John W. Campbell, on p. 55 in the July, 1962 _Analog_. Titled “Science Fiction Heat-Ray?”, it talks about GE using Lasers (capitalized, no less!) to drill precision holes in diamonds and hard alloys–so Campbell is specifically saying that yes, a heat ray is possible after all!
I never saw the article myself; I only heard about it. Maybe the version I heard exaggerated how close in time it was to the invention of the laser. Or maybe it’s just a legend.