Diana Hsieh posts this story, about supposedly educated people. I’d like to think it’s apocryphal, but sadly, I’ve had too many similar experiences to think so. She, and husband Paul, via whom I found the link, say it’s good for a laugh, but I don’t find it very funny.

About 6-7 years ago, I was in a philosophy class at the University of Wisconsin, Madison (good science/engineering school) and the teaching assistant was explaining Descartes. He was trying to show how things don’t always happen the way we think they will and explained that, while a pen always falls when you drop it on Earth, it would just float away if you let go of it on the Moon.

My jaw dropped a little. I blurted, “What?!” Looking around the room, I saw that only my friend Mark and one other student looked confused by the TA’s statement. The other 17 people just looked at me like “What’s your problem?”

“But a pen would fall if you dropped it on the Moon, just more slowly.” I protested.

“No it wouldn’t,” the TA explained calmly, “because you’re too far away from the Earth’s gravity.”

Think. Think. Aha! “You saw the APOLLO astronauts walking around on the Moon, didn’t you?” I countered, “why didn’t they float away?” “Because they were wearing heavy boots,” he responded, as if this made perfect sense.

As the piece points out, this was a philosophy major, who would have presumably had a class or two in logic. There was a time that philosophy majors could, and would have been expected to understand physics, because physics and science itself was in fact an outgrowth of philosophy (it was called “natural philosophy”). That day seems, sadly, to be past. But how can anyone this appallingly ignorant be considered well or broadly educated?

And even worse, he didn’t realize how ignorant he was–he probably thought himself well enlightened on the subject, and more than competent to lecture to his lesser undergraduates. He was “don’t know squared” (which is sadly, for obvious reasons, often the case).

Equally sadly, I have a similar story from the aerospace industry itself. Back when I worked at the Aerospace Corporation, a couple decades ago, I was fresh out of school, and sitting in a meeting with more senior people, discussing a conceptual design for a new military geostationary satellite. The subject was how to provide orientation. The two traditional choices were spin stabilization (many of the Hughes communications satellites used this technique) and active reaction control, which was more accurate, but limited the lifetime, due to depletion of propellant.

I (or someone, but I think it was me) suggested using gravity gradient stabilization (that is, taking advantage of the fact that a non-spherical satellite will naturally orient itself in the local vertical position, due to differential tidal forces between the line of the orbit and the small distances of the appendages from that line). The response of one of the supposedly experienced engineers was, “There’s no gravity gradient at geosynchronous altitude.”

I was a little surprised. “Oh, you mean there’s not enough to do the job?” (I was thinking that perhaps he’d already considered it, and run the numbers.)

“No, there is no gravity gradient effect that high–it only applies in LEO.”

Note that he wasn’t making a quantitative argument, he was making a qualitative one. Low orbits had gravity gradient, high ones did not.

Being much his junior, I didn’t want to get into an argument about it, but my boss, who was also attending, happened to be Vladimir (Val) Chobotov, author of books on orbital mechanics and a reigning expert on the space debris problem, so I figured he’d speak up. He didn’t.

Walking back from the meeting with him, I asked him what that was all about. It turned out that I was right, but he hadn’t thought it worth getting into it with him in the meeting. We later wrote up a paper suggesting it.

What happened? Sometimes even engineers don’t always apply good scientific principles. In this case, I suspect that he was an airplane guy who’d migrated into the space business (as often was the case in the beginning decades in the space industry), and had never really learned the fundamentals of orbital mechanics, or the underlying principles. Instead, he’d probably taken a space systems design course, and been given a lot of engineering rules of thumb, one of which was, no doubt, that gravity gradient can be used in LEO, but not in GEO.

And that’s not a bad rule of thumb, as long as you understand where it comes from. Gravity gradient is indeed much less at twenty thousand miles altitude than at two hundred miles, and for most satellites could be considered, for practical purposes, to be non-existent. But we weren’t talking about most satellites–we were looking at a new concept, much larger than anything previously deployed in GEO, with long booms and appendages that might, in fact be used for G-G stabilization. But because he didn’t understand the physics, he mistook a rule of thumb for natural law, even though the law of gravitation says that the earth’s gravity extends out to infinity, though it drops off as the square of the distance. As evidence that it works much farther away than GEO, consider an object over ten times as far again (the original subject of this post), the Moon.

The Moon’s rotation rate is exactly the same as its orbital period. As a consequence, it always shows the same face to the earth–we never saw the “back” side of it until we sent the first probes in the 1960s. Isn’t this an amazing coincidence, that the two rates would coincide so that the view from earth was always the same?

No.

The moon is in what’s called a tidal lock, another way of saying that it’s stabilized by the gravity gradient. It’s not perfectly spherical–it’s a little unbalanced, and one side has a little more mass than the other. Over the eons, gentle but persistent gravity gradient torques have oriented it into its present state and stabilized it there, always with the heavy side either facing away, or toward the earth, and thus it always presents the same view in the sky.

And of course, had we wanted to have a discussion of the issue in that meeting, that’s exactly the example I would have used then.

But to get back to the original topic, this to me is another example of C. P. Snow’s two cultures (well described in Pirsig’s Zen And The Art Of Motorcycle Maintenance): the liberal arts types who are ignorant of mathematics and science (and often perversely proud of the fact), and the scientists and engineers who have to actually make things work.

[Update at 12:14 PM PDT]

For those who didn’t get enough spacecraft dynamics in this post, go check out this little discussion of Explorer I from Professor Hall, who’s back from his motorcycle trip to Montana.

Listening to Bush speak out against cloning spurred me to sign the petition here. This is the first issue on which I think that I would have preferred Gore.

In a post about the recent finding that first-cousin marriage carries a lower risk of genetic defect than previously thought, Charles Murtaugh says:

…although we consider it tragic that a Huntington’s patient might have affected children, we aren’t repulsed at the very idea of allowing him or her to reproduce. This suggests that our repugnance at brother-sister incest (which carries a much lower than 50% risk of Huntington’s-level disease) has little if anything to do with genetics. Score one for Leon Kass’s “wisdom of repugnance” thesis.

I don’t think so. An evolutionary-psychology explanation for such repugnance (and in fact, all repugnance–after all, repugnance is an emotion, and emotions are just our genes’ way of getting us to do what they want) is that it evolved precisely as a result of the evolutionary benefit of not getting it on with your siblings.

But not all evolutionary adaptations are advantageous in the modern world. What repulsed us on the savanna is not necessarily something to be feared, or disgusted by, in the twenty-first century. Repugnance is like any other feeling–consider it a suggestion, rather than a mandate. Repugnance, by itself, cannot provide an infallible basis for laws, particularly when it’s not universal.

I share most people’s repugnance about incest–I feel none about cloning, regardless of what Professor Kass thinks (or, to be more accurate, feels). Unlike him, I can distinguish between blind evolutionary urges, and true wisdom, which is a much more recent human development.

In a post about the recent finding that first-cousin marriage carries a lower risk of genetic defect than previously thought, Charles Murtaugh says:

…although we consider it tragic that a Huntington’s patient might have affected children, we aren’t repulsed at the very idea of allowing him or her to reproduce. This suggests that our repugnance at brother-sister incest (which carries a much lower than 50% risk of Huntington’s-level disease) has little if anything to do with genetics. Score one for Leon Kass’s “wisdom of repugnance” thesis.

I don’t think so. An evolutionary-psychology explanation for such repugnance (and in fact, all repugnance–after all, repugnance is an emotion, and emotions are just our genes’ way of getting us to do what they want) is that it evolved precisely as a result of the evolutionary benefit of not getting it on with your siblings.

But not all evolutionary adaptations are advantageous in the modern world. What repulsed us on the savanna is not necessarily something to be feared, or disgusted by, in the twenty-first century. Repugnance is like any other feeling–consider it a suggestion, rather than a mandate. Repugnance, by itself, cannot provide an infallible basis for laws, particularly when it’s not universal.

I share most people’s repugnance about incest–I feel none about cloning, regardless of what Professor Kass thinks (or, to be more accurate, feels). Unlike him, I can distinguish between blind evolutionary urges, and true wisdom, which is a much more recent human development.

In a post about the recent finding that first-cousin marriage carries a lower risk of genetic defect than previously thought, Charles Murtaugh says:

…although we consider it tragic that a Huntington’s patient might have affected children, we aren’t repulsed at the very idea of allowing him or her to reproduce. This suggests that our repugnance at brother-sister incest (which carries a much lower than 50% risk of Huntington’s-level disease) has little if anything to do with genetics. Score one for Leon Kass’s “wisdom of repugnance” thesis.

I don’t think so. An evolutionary-psychology explanation for such repugnance (and in fact, all repugnance–after all, repugnance is an emotion, and emotions are just our genes’ way of getting us to do what they want) is that it evolved precisely as a result of the evolutionary benefit of not getting it on with your siblings.

But not all evolutionary adaptations are advantageous in the modern world. What repulsed us on the savanna is not necessarily something to be feared, or disgusted by, in the twenty-first century. Repugnance is like any other feeling–consider it a suggestion, rather than a mandate. Repugnance, by itself, cannot provide an infallible basis for laws, particularly when it’s not universal.

I share most people’s repugnance about incest–I feel none about cloning, regardless of what Professor Kass thinks (or, to be more accurate, feels). Unlike him, I can distinguish between blind evolutionary urges, and true wisdom, which is a much more recent human development.

I’ve been spending a few days up in the Reno area, and since the President’s decision to go ahead with the Yucca Mountain nuclear waste repository, it seems to have moved up in the local political agenda. Senator Reid is accusing Bush of “lying” and breaking his campaign promise, but of course, this is just demagoguery–Bush promised nothing except to make a decision based on “sound science.” Since most politicians wouldn’t know sound science if it came up and yelled in their ears, I’m not inclined to grant the Senator much credibility here–it’s really a judgment call. Mr. Bush may be mistaken, but he can’t be objectively accused of promise-breaking.

The Dems here are trying to leverage it as a campaign issue against Republicans, but the consensus seems to be that this won’t have much traction, because the local Republicans are opposed to the decision as well. It doesn’t seem to be a partisan issue here–it’s viewed more as Nevada against the rest of the country. It’s just the latest manifestation of the Sagebrush Rebellion, with which I am normally sympathetic.

Unfortunately, nuclear energy and nuclear waste are not issues amenable to decisions based on sound science–people tend to get too emotional about things that they don’t understand.

There aren’t any simple solutions to this policy problem. Nuclear energy is potentially the most environmentally benign source available in the near term (though the federal policy on it has been idiotic since the inception of the industry, making it much more hazardous and expensive than it need be, by mandating intrinsically bad plant designs).

But waste disposal is probably the most pressing problem, and it’s one that’s independent of plant design. And even if we were to renounce nuclear power today (with the attendant economic and environmental damage as we either destroy local economies from energy shortages, or increase production from much dirtier coal plants which produce the evil CO2, and actually put out more radiation than properly-operating nukes), we still have tens of thousands of tons of waste sitting in unsafe conditions at existing plants.

Every criticism of Yucca Mountain applies in spades to the available alternative–continuing to accumulate it at the plants in a wide range of conditions, few of them good. If Nevada wants to fight this decision, they’ll have to do more than simply naysay it and declare that, after over two decades and billions of dollars, it needs more study. They have to offer a viable alternative.

And any alternative should consider the following: one generation’s waste is another’s commodity. Before the invention of the internal combustion engine, gasoline was a waste byproduct of cracking oil for other purposes. Thus, one of the features of the Yucca Mountain solution is that the waste will be available to us in the future when we may find it useful, and any alternative should ideally have that feature as well.

But on the bright side, another feature (well, actually, it’s a bug) of the Yucca Mountain plan is that it will cost billions of dollars and take several years to implement. This effectively lowers the evaluation bar for competing concepts–they don’t have to be either cheap or fast, as long as they’re better.

Those of you who read my ravings regularly probably know where I’m going with this. Many eons ago, when I was an undergraduate, I took a course in aerospace systems design. The class project was to come up with a way to dispose of nuclear waste–in space. While it was (of course) a brilliant study, it has also been more recently analyzed by people who both knew what they were doing and got paid for it. It turns out to be (at least technically–politics are another matter) a non-ridiculous idea.

These are the basic options: dropping into ol’ Sol, which is really really expensive, and puts it totally out of the reach of our smarter descendents; lofting it out of Sol’s system completely, which is cheaper than putting it in the Sun, but still expensive, and practically if not theoretically out of reach of future recyclers; a long-term orbit, which is accessible, but long term can’t be guaranteed to be long-enough term; and finally, on some planetary surface, most likely the Moon because it’s the most convenient.

Lunar storage sounds like a winner to me. There’s no ecology to mess up there, the existing natural radiation environment will put that particular grade of nuclear waste to shame when it comes to particle dispensing, and we can retrieve it any time we want, while making it hard (at least right now) for terrorists to get their hands on it.

So, great storage location. Now, how do we get it there? Aye, there’s the rub.

The two problems, of course, are cost and safety. It turns out that both are tractable, as long as one doesn’t use Shuttle, or any existing launcher as a paradigm for the achievable. The key to both reducing cost and increasing reliability is high flight rate of reusable systems–what I call space transports.

Fortunately, like space tourism, hazardous waste disposal may be a large enough market to allow such a system to be developed. A thousand tons is a thousand flights of a vehicle with a one-ton payload. And there are many thousands of tons of nuclear waste in storage. And the tonnage will only increase if it’s further processed for safe handling and storage (such as vitrification, in which it is encased in glass).

Preliminary estimates indicate that it can in fact be done economically in the context of the current nuclear industry operating costs; the major issue is safety. This issue has been addressed as well, and it’s something that Nevada (a state that also offers high potential as a home for rocket racing and the space tourism industry) should take seriously as a possible alternative to terrestrial storage.

If anyone in Carson City is interested, I’m available for consulting…

My little contretemps with Iain over the difference between theory and fact, and the nature of epistemology in general, inspires a rant^H^H^H^Hdisquisition on the nature of science and how it’s taught (or not).

Several years ago (probably more than a decade), I saw a special on my local affiliate of the Public Broadcasting System (so named because that’s who pays for it–not, in a manner similar to National “Public” Radio, because it’s necessarily of any particular benefit to them) called something like “The National Science Quiz.”

It consisted of a bunch of multiple-guess questions that were in fact, facts, as opposed to theories. For example, they asked something like, “How many hairs, on average, are on a square inch of the human head?”

I threw something (it’s been too long to remember what, and being a skinflint, and not one to destroy a television that I will have to pay to replace, I’m sure that it was relatively soft) at the TV.

“This is not science!” I yelled at it, ineffectually. “Very few scientists would know the answer to that question (though they would know where to look it up, if it had any relevance to a scientific inquiry). Not only is this not science, but it’s the reason that many people get turned off to science, and it’s why very few people understand anything about science!”

Science is not a compendium of “facts.” Science is about how we turn unrelated, boring facts into useful knowledge. Science is a method, not an encyclopedia. That’s why I get upset when someone says that “evolution is a fact.” Not just because it’s untrue, but because it misses the point entirely.

Science is a means of inquiry. It cannot be learned by simply memorizing a set of dry unconnected facts, but that’s what is implied by the “science quiz” described above, and much of what passes for science education in primary schools (and even more frighteningly, in many colleges and universities).

When I was in college, physics was my favorite subject.

Why?

Because I have a lousy memory (one, but by no means the only, reason that I never seriously considered going into medicine). Because I could pass the tests without memorizing a vast compendium of “facts,” (which I couldn’t manage in biology, or even chemistry, which I still don’t consider a true science, but it may become when physical chemistry reaches a sufficient degree of sophistication and maturity–perhaps it already has in the intervening decades). I could pass the tests by simply taking the few basic laws, and applying the basic rules of logic and mathematics to them, even rederiving more advanced laws if necessary, rather than having to memorize them.

What’s my point?

Learning physics wasn’t about remembering what the atomic weight of a given element was, or how many wombats lived in a given state of Australia at a given point in time. Learning physics was about learning some basic principles, and applying them to more general problems. That’s what all science should be about.

But instead science, when it’s taught at all (often by primary-school teachers who don’t understand it themselves), is taught as a body of knowledge, a set of known facts, rather than as a method of inquiry. The emphasis is not on thinking, but on memorization. Science, properly taught, opens the mind to a vast array of topics, even beyond science. Science, as it’s generally taught, is pure drudgery. It’s little wonder that most kids are turned off to the subject by the time they enter high school.

It’s also little wonder that the phrase, “it’s only a theory” has such power when attacking evolution. After all, science is about facts, right? And if evolution is “only a theory,” then it’s not a fact, and we need not believe it.

So those defending evolution must take one of two tacks–to claim (mistakenly, as occurred on the web site that Iain cited) that evolution is a “fact,” or to take the more difficult, but in the long run, much more valuable road, by performing a rectification of names. That is why I kill so many electrons to make this point, in multiple posts.

I just hope that my struggle doesn’t long remain a lonely one.