Beauty of Gray



Thursday, April 25, 2002
 

It’s still a MAD world


During the Cold War, as everyone knows, the US and the USSR engaged in a nuclear face-off whose deterrent logic of mutual destruction went by the catchy title of mutually assured destruction, or MAD. Basically, neither side could use their nuclear weapons on the other since, although they would destroy the opponent, the retaliatory strike would in turn destroy them. A good enough idea, as far as it went. There were, of course, some wrinkles, and a lot of folks at RAND and elsewhere made a pretty good career of analyzing the situation using game theory and other tools.

In fact, in the early years, there were some theorists who became a bit too enamored of their models and decided that the most “rational” course of action for the US was a first strike against the Soviet Union, before they could build up their arsenal to the point that the MAD equilibrium was established. Which illustrates the important principle that game theory, or any other econometric analysis, is not the alpha and omega of politics. It is merely one tool, one source of input for the decision makers to weigh in the balance. But that’s neither here nor there.

Now, in the new multi-polar world, it is much less clear what role, if any, MAD plays. What is the role of nuclear deterrence in the current world situation—how does the current and potential future nuclear proliferation, combined with the threat of terrorism, affect the analysis? The problem has two main components.

First, there is the problem of hostile states acquiring nuclear weapons. Iraq, Iran, and North Korea now, with the list likely to grow in the future. Robert Wright has argued, convincingly, that the old MAD logic of deterrence still works against these states acting as states. That is, that even if Saddam Hussein acquired nuclear warheads, he wouldn’t dare launch a missile at the US or Israel, since that would lead to his and Iraq’s destruction. This is true, as far as it goes, but Wright’s conclusion—that we hence shouldn’t worry overmuch about Iraq’s nuclear program—is false, for three reasons. The first is that, while the US is still protected by MAD logic, Iraq (or whatever country gets the bomb) will also be protected by this same logic. So that letting them acquire nuclear weapons is a tremendous blow to US interests. Not because Manhattan will become a nuclear crater, but because it will severely handicap our future efforts against Iraq.

Second, once Saddam did get a warhead or two, there would be a strong pressure on him to use it. During the Cold War, there were those that argued that pursuit of a missile defense system would actually destabilize the situation, since the previous balanced MAD situation would then become unbalanced. And the weaker side (in the Cold War argument, the USSR) would then have no guarantee that their second strike capability would survive a US first strike. So then, in the MAD game, the USSR is vulnerable to a US first strike, which argues for a Soviet first strike of their own. Use it or lose it. Similarly, if Hussein got a bomb, he would still be in the US crosshairs, and would know that his single bomb (or small number of warheads) could be taken out by a US strike, or he could be toppled from power. Which would exert a pressure on him to use the warheads he had, before he lost them.

The final reason why Wright’s sanguine conclusion is misguided ties into the second problem, nuclear terrorism. If Saddam got nuclear warheads, it is possible and perhaps even likely that he would assist al-Qaeda and other terrorist organizations in their own bomb building efforts. And how can nuclear deterrence work against a foe that is willing to sacrifice their own life to kill Americans and presents no obvious target for retaliation?

So what, if anything, can we take from the old MAD arguments to apply to the present situation? First, while in the case of The USSR, the first strike argument I saw didn’t make sense from a moral or practical standpoint—while it would “win” the game, it would do so at an unacceptably high cost—in the current situation it does. In part because we can attack Iraq (and the other countries pursuing nuclear weapons) with conventional means. So a “first strike” by the US in this case can be done without the death of millions which ruled out this possibility in the Cold War. Pre-emptive US action (as we seem to be on our way to undertaking) is the most rational course of action. No real surprise there—people have been arguing for this for a while—but it’s worth noting that these arguments for action do have a pedigree.

As for the problem of terrorist nukes, obviously the same logic still applies—the best defense is a good offense. But I also think it might be possible to restore some of the deterrence that put the teeth in MAD. A deterrent works if you can threaten the terrorist with a negative consequence that outweighs the value they place on nuking a US city. For the reasons described above, a threat on their own life is neither credible nor, even if it were, would it be a strong deterrent.

Given that the international terrorist problem is wholly an Islamic problem, the question then becomes what can we threaten with nuclear weapons which would deter a radical Islamic terrorist? Perhaps it’s an inaccurate psychological read, but it seems to me that a threat of retaliation against Mecca, as briefly discussed over in the Corner at NRO, could be a viable deterrent. Would a radical Muslim be willing to trade half of Manhattan for all of Mecca? My guess is no.

And while this would almost certainly completely alienate most of the Moslem world from the US, it would have the added benefit of making all the Islamic countries work extra hard to try and prevent any nuclear terrorist attack on the US. If it worked, I could deal with a little bit of extra hatred from the rest of the world. I’d rather that than to die along with 100,000 others in a nuclear attack on the White House.

It’s a brutal and cold course of action, but then nuclear deterrence is not bright and cheery field. I’m not sure why threatening to nuke dozens of cities and kill tens of millions was considered reasonable, yet many would probably be horrified by this suggestion. I'm not saying we should actually do it, or that nuking Mecca or any city would be anything other than an awful act. But threatening to do so could be beneficial.

I haven’t completely thought this through, so I’d certainly be interested to hear why I’m crazy to suggest this. But if I can’t post uncertain but interesting ideas to my blog, then what good is having one?


Link posted by Doug Turnbull at 5:37 PM



Tuesday, April 23, 2002
 
Semiconductor Lighting


There was a post on neat gadgets over the USS Clueless a couple of days ago, in which he mentioned that they now sell LED flashlights. I’ve lost track of the field, but this indicates to me that we are relatively close to realizing what has been a holy grail of the optoelectronics field for over ten years: practical semiconductor lighting.

Currently, most light bulbs are incandescent—they work by heating a filament up to a high enough temperature that it glows. However, this is a very inefficient lighting method, because the heated filament emits radiation across the entire electromagnetic spectrum. (This emission is called blackbody radiation, and all objects emit it. But the intensity and distribution of the emitted light depends on the temperature, so only objects that get very hot emit enough visible light to glow. Cooler objects emit light mostly at lower energies, in the infrared, which is why IR cameras can detect people in the dark. Understanding why blackbody radiation works the way it does was actually one of the first discoveries on the road that led to quantum physics. Classical theories failed in their explanations, a failure which went by the cool sounding name of the “ultraviolet catastrophe.” But I digress.)

Anyway, incandescent bulbs are inefficient because a lot of their energy is being emitted in the infrared rather than the visible. This is why light bulbs get hot to the touch when used—instead of all the energy going into light, a lot is being wasted as heat. Incandescent lights are something like 10% efficient—about 10% of the energy put in is converted into visible light.

The next step up is fluorescent lighting. In fluorescent lights, a gas is ionized by the application of an electric field, and then a lower electric field keeps a current running through the gas, which excites the gas molecules. When the gas molecules relax, they emit ultraviolet light. (If you remember your high school chemistry, the electrons in atoms have specific allowed energy levels they can inhabit. The current is exciting the electrons into a higher energy level, from which they can relax back to the ground state by emitting a photon—a little bit of light—of a certain energy.)

This emitted UV light in turn is absorbed by a phosphor coating the inside of the bulb, which in turn emits the white light those bulbs give off. Fluorescent lights are much more efficient, wasting a lot less of the input energy as heat. But the phosphor conversion itself wastes a fair amount of the energy, so their efficiencies are only on the order of 50%. Also, while some advances have been made, you are limited by the nature of the phosphors to the relatively cold white light characteristic of fluorescents.

Which brings us to what will be the next step in the process—semiconductor lighting. Semiconductor lights work by combining several LEDs of different wavelengths together into a single structure. LEDs are just junctions of two different types of semiconductor. While individual atoms have strictly defined energy levels that electrons can inhabit, the interactions among neighboring atoms in a solid change these discrete levels into bands—ranges of energy that are allowed for electrons, and which can hold many electrons rather than just one. When you send a current through a semiconductor, the electrons are moving through in one of the excited states—the higher lying bands. Just as with an individual atom, these excited electrons can relax to he ground state by emitting light.

LEDs are extremely efficient because they work via a one-step process that results in the emission of visible light. Almost every electron you send through the diode will end up relaxing and emitting light. So you can get about a 90% efficiency. Furthermore, diodes are in theory pretty easy to make, so they can be very cheap. And while individual LEDs basically emit light only at a single wavelength, by combining several of them (just as your TV combines 3 different color pixels to produce the full color range) at different powers it is possible to create light of any color you wish. So you can get the warmth of incandescent light with an even higher efficiency than fluorescents.

The hold up until recently has been trying to develop practical blue light emitting diodes. For different wavelengths, you need to find different semiconductor materials, and it turns out that the semiconductors for blue LEDs are a real pain in the ass to work with, so it’s been a struggle to make ones that are cheap enough and have a long enough lifetime to be sold in commercial applications like light bulbs. (And you can’t get a full spectrum of light without blue. Without a blue LED, the light would look orange or reddish.) But the big breakthroughs have been made and prices are coming down. I’d expect that within a decade you’ll be able to buy solid state light bulbs to plug into your lamps. Which will be great for HP and other similar companies, and bad for any companies that make glass bulbs or filaments to go in them.

Already LEDs are moving into many fields formerly ruled by incandescent bulbs, where red light (rather than white) is acceptable. The running lights on many semis are actually red LEDs, and more and more you’re starting to see breaklights (especially the third, central light) made up of a grid of LEDs rather than a big single incandescent.

It won’t revolutionize your life, but it’s one of those many incremental, evolutionary changes that go on all the time, which together add up to real, significant advances; the everyday wonders that so many Sci-Fi books and movies utterly fail to capture.


Link posted by Doug Turnbull at 1:26 PM



Monday, April 22, 2002
 
Dumbest. Plan. Ever.


This is from a UPI story, via JunkYardBlog:

"We tried to make them go down there," the boy said. "We had a lot of very good snipers, and we were going to make them come out of the tanks and shoot them one by one."

When I asked him how they planned to do that, he looked at me like someone who had to have everything explained to him in children's terms and his tone of voice was like that of an old man telling stories to a little boy. He said he was just over 8 years old.

"The streets are too narrow. They cannot drive the tanks through them quickly. They get stuck and one or two always come out and wave at it until it is free," he said, imitating the hand signals he saw them using. "Then we shoot them."


I'm really at a loss. This is just so stupid I can't even critique it without feeling dumb.These idiots apparently really thought that (a)- The Israelis would drive their tanks down into a narrow alley without securing it or widening it. (b) They would keep driving until it got wedged. (c) They would choose not to just smash through the buildings in order to break free, but would (d) get out to survey the situation and (e) after the first guy out got shot, then a second crewman would get out to see what was taking so long.

Any one of these five assumptions is so dumb it beggars belief. But apparently there was a group of Palestinians who came up with a "plan" that depended on all five of them happening. I was planning on writing a post extolling how amazing and near-miraculous the performance of the IDF in Jenin was, but if this was the quality of the opposition, their success is suddenly much more understandable.

Link posted by Doug Turnbull at 2:12 PM







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