Stardate 20020327.1951

(On Screen): The current attention being paid to "dirty" bombs is, to some extent, almost eagerness. It's strange, but it almost reads that way. Nuclear weapons have attained almost mythical status; there's almost a millennial feeling about them, where if any are ever used then we can count down the minutes until the end of the universe (since, of course, the universe will end when all humans are gone).

And as a result, nearly anything nooklyar looms large in some minds. So when it was discovered that al Qaeda was attempting to produce a fission device by attempting to purchase enough fissionable uranium to make a weapon, there was notable panic. And then when it turned out they'd been rubes and had bought U-238, which is about as explosive as concrete, rather than breathe a sigh of relief the heart then fondly turned to the idea of a dirty bomb. We deserve to get some sort of nuclear weapon here, folks. We've earned it.

Or so it seems. And somehow a dirty weapon seemed more likely, since you didn't have to have purified isotopes or anything, let alone a critical mass; you just needed "some" radioactive stuff which you put next to a conventional explosive and detonated. Definitely low tech, and since it's nooklyar it's nearly as scary.

NASA has run into this problem. Satellites and probes intended for use inside the orbit of Mars can be powered by photocells, but if the probe is intended for the outer solar system that won't work. So all the satellites intended for the outer system are powered by nuclear power plants; they use the heat of breakdown to make electricity. The Cassini probe which is on its way to Saturn now has more than 70 pounds of Plutonium on it. In order to save money, Cassini wasn't launched with a rocket big enough to put it into an escape orbit. Instead, it made a series of gravity encounters with inner planets each of which give it additional speed (by very slightly slowing the planet down). One of those encounters was with the Earth itself.

But, but, but... but it's carrying plutonium. What if it hits the earth? 70 pounds of plutonium would be dispersed into the atmosphere and bazillions of people would die. Well, no; far more plutonium than that was vaporized during the atmospheric nuclear tests of the 1950's. Tons, in fact. But the activists weren't going to listen to reason, and they went to court.

And literally tried to get a court order to force NASA to change the orbit away from the earth, which would have wasted the probe. Fortunately, the courts didn't play along. As it turns out, the Earth encounter went beautifully, and Cassini is now past Jupiter (its last inner encounter, giving it the last boost it needed) and is well on its way to Saturn.

This news article talks about how there were ampoules of Plutonium which were given to other nations over the course of the last fifty years for use as calibration references, with the intimation that the bad guys may have come up with one or more of them and could use it to make a dirty bomb.

Much of this is built on top of decades of anti-nuke propaganda about how deadly plutonium is. You would hear stories about how plutonium is the most deadly substance known (not even close, folks) and how a gram of it is capable of killing umpteen bazillion people. So when you hear of a dirty bomb with a few ounces of plutonium it gives you images of death tolls approaching Hiroshima. (And thus you get your money's worth.)

But for Plutonium to produce that kind of death toll, it would basically require administration in a hospital setting. You would have to carefully divide the stuff up, and then surgically implant an exact dose of it in each victim where it would do the most good (harm). In actual practice, a "dirty bomb" is immensely inefficient. It's really little more than a nuisance; it would kill some people from the immediate blast, and some more people from radiation effects, and render an area pretty much useless.

In other words, it would be about the same as a toxic waste spill, which is not good, but not really a catastrophe, either. Those mythically high fatality rates for Plutonium are based mainly on the assumption that the proper dose would be implanted in the lungs and would cause lung cancer over a period of years, and indeed a little of that would happen. (The dose required to kill you in hours from direct radiation exposure is vastly higher, by the way.)

We actually already have quite a lot of experience with contamination with radioactives. It predates WWII, in fact. Time was when you could buy clocks and watches whose dials glowed in the dark. You can't get those any more, but I remember them from when I was a kid. The hands and numbers would have a kind of thick green paint on them. The paint contained Radium.

There used to be factories which made that paint, and others which produced the clock dials. Back then they didn't really know what they were doing, and the paint was not really treated with respect. It got all over the place, and there are now areas contaminated with Radium.

Radium is also dangerous. It doesn't have the same mode of fatality as Plutonium, though. Radium is chemically in the same family as Calcium, and if you ingest it your body takes it to your bones, where it will give you leukemia. But dead is dead; it really doesn't matter too much how you die.

So some of the Su