Friday, July 6, 2007

Death Rays and Disintegrators

Sometimes they were called "blasters, ray guns, or even zap guns," although that last one was sometimes also used for the "stun gun" the puny sibling to the much mightier Death Ray. Asimov had one called a "Disinto." Hugo Gernsback was sure they’d be either radio waves or powered by radium. Fritz Leiber imagined the "fission pistol," that had all the nuclear reactions in the gun going in the same direction. A. E. van Vogt used light to "conduct" nuclear reactions to the target, at least on the Space Beagle. In Slan, it was just raw atomic power. Once in a while the death rays were "sonic." More frequently they were "electron guns" which actually exist in television sets, but for something else entirely (though one may argue that TV is something of a stun device). H. G. Wells began the whole thing with the "heat ray."

And we wanted them, maybe as much as we wanted to go into space (which is maybe why I wasn’t as interested in the things as my fan boy brethren). And it wasn’t just us. During WWII, the U.S. Army's Aberdeen Proving Ground offered a standing reward to anyone who could demonstrate a death ray capable of killing a tethered goat. Britain's Air Ministry put up a similar prize to the inventor whose ray could kill a sheep at a range of a hundred yards. There’s a story that radar was invented partly because of a 1934 rumor that Germany had invented a microwave-based death ray.

Because hell, nobody messes with you if you’re packing a Death Ray.

So when lasers were announced in 1960, and we all heard that one could punch a hole in a diamond, or a metal plate, well, in a lot of manuscripts the word "blaster" got crossed out and "laser" got inserted.

Trouble was, they didn’t work like that. They were made of light.

Remember all those tales about the magic spell that is deflected by the mirror? Well, dang, you could do that to a laser, it turned out. Also, fog, smoke, not so good.

Moreover, they were damned inefficient. You had to put in kilojoules to get out joules. Later, some of them got more efficient, and some, like the CO2 laser, could be pumped by chemical reaction. I read about a 4000 watt laser in the late 1960s, from Raytheon, as I recall. It was powered by a gas turbine, basically a jet aircraft engine, and it was chemically pumped. But notice, a jet engine to pump a laser that has the output of—a couple of hair driers. (I’m talking continuous power here, the pulsed ones can put out more power than the whole U.S. power grid—for a picosecond).

CO2 lasers can get up to pretty high efficiencies these days, about 20% and some of them are upwards of a hundred kilowatts. But consider, to get water from room temperature (about 20 degrees C) to boiling, you need top put about 330 kilojoules into it for every kilogram (about a half gallon). The heat of vaporization of water is about 2260 kilojoules per kilogram. So to boil a half gallon of water, you need around 2600 kilojoules. It takes even a 500 kilowatt laser 5 seconds to boil a half gallon of water.

You're also boiling four times that much water in your cooling system, incidentally.

Yeah, it’ll hurt you plenty quick if you stick your hand in a laser beam that powerful, but we’re sure not in disintegrator ray territory. Not by a long shot. Was James Bond about to get his testicles cut off and be severed in two? Probably not; the thing would have set his clothing on fire, though.

So the "laser death ray" future turns out to be one that dated faster than just about any other sci-fi gimmick ever. Still, the "phaser" was a brilliant neologism. It took the "-aser" suffix, which still has some mysterioso power, even now, and added, well, what? More mysterioso. Something to do with "phase" probably. So soon it was "phaser" and "plasma rifle" and "hypervelocity rail gun," as everyone took a quick swing back into fantasy land, which is what Space Opera is all about anyway. Nobody took the Laser Death Ray seriously after that.

Except, it turns out, for the Department of Defense. I think they’re still pushing space-based laser missile defense systems. These have the positive aspect of being largely harmless hogwash, good for tech pork and not much else. Physicists still love them some laser macho, and between the space lasers and attempts to use lasers to light fusion reactions, they get to keep playing, I’ve Got the Big One.

Dr. Evil: You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads! Now evidently my cycloptic colleague informs me that that cannot be done. Ah, would you remind me what I pay you people for, honestly? Throw me a bone here! What do we have?

Then there is the saga of the Gamma Laser or X-ray Laser, but I’ve already written about that one.

And then there’s the one about using an ultraviolet laser to conduct a taser current (there’s that –aser mojo again). Look ma! We have a stun gun!

Too bad all you have to do is wear a wetsuit or a rubber raincoat to be immune. There’s a reason why real tasers have little sharp barbs at the end.


JP Stormcrow said...

Found this the other day, when I was looking for YouTubes for your post on the H-bomb. It is a History Channel segment that describes Japanese attempts to build a microwave death ray during WW II.

James Killus said...

Cool. Thanks. I will review it in my Copious Spare Time.

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